A Systematic Review of Subjects for PG Medical Entrance Examinations Pradip Kumar Das
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GENERAL DISCUSSION1

PAIN
 
PAIN PATHWAY
zoom view
 
Neurotransmitter
  • For fast pain is Glutamate.
  • For slow pain is substance P.
 
PAIN PHYSIOLOGY
 
Visceral Pain
Viscera are relatively insensitive to noxious stimuli under normal circumstances. True visceral pain is produced by distension of a hollow viscus, spasmodic contraction, ischemia.
Cutting does not induce visceral pain (also crushing or burning).
 
Neuropathic Pain
Pain produced by damage or dysfunction of the nervous system e.g. – diabetic neuropathy.2
 
Chronic Pain Syndrome
Sympathetically maintained.
  1. Causalgia – Severe burning pain produced by peripheral nerve injury in the region innervated by the nerve.
  2. Reflex sympathetic osteodystrophy –
    Most common cause is Colles' fracture of forearm.
    Clinical feature: Pain, stiffness and swelling of hand. The overlying skin is tense and shiny.
    Treatment: Sympathetic (stellate ganglion) block.
  3. Spontaneous pain is seen in thalamic syndrome due to damage of posterior thalamic nuclei caused by obstruction of posterior cerebral artery.
Note: Indications of sympathectomy:
  1. Hyperhydrosis (NOT anhydrosis)
  2. Causalgia
  3. Reflex sympathetic osteodystrophy
  4. Frost bite
  5. Raynaud's disease
  6. Thromboangiitis obliterans
  7. Claudication – not very effective, but indicated to relieve rest pain and ulceration (ischemic).
Note: Allodynia means perception of nonpainful stimulus as painful.
 
Referred Pain
Pain from a viscus may be felt at some somatic structure which may be a considerable distance away. Such referral of pain is due to convergence of nerve fibers from the viscus and somatic structure at the spinal cord.
For example, pain from diaphragm is referred to the tip of the shoulder because both are supplied by phrenic nerve.
 
CHEST PAIN
 
Anginal Pain
Typically develops on exertion, after heavy meals or emotional stress, not affected by position, respiratory movement, etc. and resolves 5 – 30 minutes.
Site: Substernal region, anterior mid-thorax.
Diagnosis: Pain is relieved more quickly (within 5 min) and more completely with sublingual nitroglycerine.3
Myocardial infarction: Similar to angina but of more intensity and greater duration. Pain often radiates to left arm. Not relieved by rest or nitroglycerine. Accompanied by diaphoresis, nausea and hypotension.
Pericarditis: Pericardium is pain insensitive. Pericardial pain is due to involvement of overlying pleura. Infectious pericarditis, nearly always involves the pleura and is always associated with pain. It is brought on by swallowing. Aggravated by cough and / or deep inspiration. Relieved in upright sitting position with body leaning forward.
 
HEADACHE
Pain sensitive structures in cranium are – the scalp and aponeurotica, middle meningeal artery, dural sinuses, falx cerebri and large pial arteries.
 
Lumbar Puncture Headache
Occipitofrontal headache following lumbar puncture (usually within 48 hours). It is typically positional, increases on sitting and decreases on lying down. Last for 7 – 10 days.
Cause – Leakage of CSF.
Prevention: Using small (25 G) bore needle.
Treatment: IV caffeine sodium benzoate.
 
Other types of headache
See neurology section.
 
BACK PAIN
 
Disc Prolapse
Site: Between L4 – L5 in lumbar spine (most common), C5–C6 in cervical spine.
Tests: To detect nerve root compression –
  1. Straight leg raising test.
  2. Lasegue test.
Defect:
  • L4 root: Weakness of extensors of the knee. Knee jerk sluggish or absent.
  • L5 root: Weakness of extensor hallucis longus normal and dorsi-flexors of foot. Ankle jerk normal.
Investigation: MRI is the investigation of choice.4
Treatment:
  1. Surgery – Microdiscectomy is done in a case of postero- lateral prolapse of disc.
  2. Chemonucleosis – Injection of chymopapain into the disc.
Note: Inverted Lasegue sign is seen in lesion of L3.
 
Spinal Stenosis
Compression of cauda equina.
Pain radiating down the lower limbs induced by walking and relieved by rest (pseudoclaudication).
 
Spinal Tumors
Most common spinal tumors are secondaries from breast (most common), lung, prostrate, etc.
zoom view
Multiple myeloma is the most common primary tumor of spine.
Neurofibroma is the most common intradural tumor.
Note: Extramedullary tumors produce pain, early involvement of corticospinal tract and loss of sacral sensations. CSF protein is raised.
 
Sciatica
Pain radiating down the back of thigh and calf.
Cause: Degenerative arthritis, disc prolapse.
 
SHOULDER PAIN
 
Thoracic Outlet Syndrome
 
Cause
Cervical rib syndrome (7th cervical spine, usually unilateral, more commonly on right side).5
  • Scalenus anterior syndrome.
  • First thoracic rib syndrome.
  • Costoclavicular syndrome.
Structures compressed are:
  • Nerve – lower trunk of brachial plexus (4th first dorsal nerve, ulnar nerve).
  • Artery – subclavian artery.
 
Clinical Feature
Neurogenic: Shoulder pain radiating down the arm, decreased sensation on the palmar aspect of 4th and 5th digits, weakness of the intrinsic muscles of hand.
Vascular: Pain in forearm which is induced by the use of the arm and relived by rest. It is due to ischemic changes in the muscles of the arm.
 
Test
  • Adson's test – pain is accelerated if the arm is in raised position at the time of exercise.
  • Costoclavicular compressive test.
  • Hyperabduction test.
 
Treatment
Prompt extraperiosteal excision of the cervical rib.
 
Brachial Plexus Disease
Lower trunk is most commonly involved. Symptoms are as above.
 
Cause
  1. Squamous cell Ca of lung – most common (Pancoast tumor).
  2. Postradiation fibrosis (Breast Ca).
Lower trunk disease may be associated with Horner's syndrome (ptosis, miosis, anhydrosis, enophthalmos and loss of ciliospinal reflex) due to involvement of lower cervical sympathetic ganglion (Stellate ganglion).
Note: Deformities in brachial plexus injury:6
 
Erb's Palsy
 
Cause
  • Injury (e.g. – birth trauma) to the upper trunk.
  • Nerve roots involved – mainly C5, partly C6.
 
Deformity
Arm: Adducted and medially rotated.
Forearm: Extended and pronated. This is known as ‘policeman's tip hand’ or ‘porter's tip hand’.
 
Disability
Movements lost are:
Arm: Abduction and lateral rotation.
Forearm: Flexion and supination.
 
Klumpice's Palsy
 
Cause
Injury to the lower trunk. Nerve roots involved – mainly T1, partly C8.
 
Deformity
‘Claw hand’ –hyperextension of the MCP joints and flexion of IP joints. Horner's syndrome may be present.
1. Injury to nerve of Bell
(long thoracic nerve – C5, 6, 7) which supplies serratus anterior.
Deformity: Winging of scapula.
Disability: Loss of pushing and punching actions. Inability to abduct arm beyond 90°.
TEMPERATURE
 
PHYSIOLOGY
Normal body temperature is 36.8°C ± 0.4°C (98.2°F ± 0.7°F).7
Circadian rhythm: body temperature is maximum at 6 pm and minimum at 6 am (AM nadir and PM peak).
Measurement: the following temperatures reflect the core temperature.
  1. Rectal – most accurate, 0.5 – 1°F higher than oral temperature.
  2. Lower esophageal.
  3. Freshly passed urine.
Regulation: By preoptic anterior (heat) and posterior (cold) hypothalamus.
Heat acclimatization: Increase sweating to dissipate heat and conservation of fluid otherwise (decrease renal blood flow, increase aldosterone secretion which leads to Na+ retention and low urinary Na).
 
FEVER AND HYPERTHERMIA
 
Fever
AM temperature > 98.9°F or PM temperature > 99.9°F.
Pyrogen: Endotoxins (lipopolysaccharides), cytokines – IL-1α, IL–1β, TNFα, IFN–α, IL–δ.
 
Hyperpyrexia
Temperature > 106°F.
Causes: Malaria, septicemia, encephalitis, pontine hemorrhage, lobar pneumonia, heat stroke, datura poisoning.
Malignant hyperthermia: Neuroleptic malignant syndrome.
 
Types of Fever
  1. Intermittent – Fever present only for several hours and always touches the baseline.
    Causes:
    1. Quotidian – occurs daily. E.g. – Double infection with P. vivax.
    2. Tertian – Fever occurs on first and third days (48 hours apart). E.g. – Benign tertian malaria (P. vivax), malignant tertian malaria (P. falciparum).
    3. Quartan – Fever on first and fourth days (72 hours apart). E.g. – Quartan malaria (P. malariae).
      8
  2. Continued/Sustained – Fluctuation <1°C and temperature never touches baseline. E.g. – Lobar pneumonia, second week of typhoid fever, Meningococcal meningitis.
  3. Remittent – Daily fluctuation > 2°C but never touches baseline. E.g. – Tuberculosis, viral infections and amebic liver abscess.
  4. Relapsing fever – Borrelia burgdorferi.
  5. Pel–Ebstein fever – fever lasting 3–10 days followed by afebrile periods of 3–10 days. Classically seen in Hodgkin's lymphoma.
  6. Fever of cyclic neutropenia – fever occurs every 21 days and accompany the neutropenia.
 
Pulse-Temperature Ratio
With every 1°F rise in temperature there is increase in pulse by 10 beats/min.
Relative bradycardia – is seen in typhoid fever, brucellosis, leptospirosis, acute rheumatic fever.
Relative tachycardia – seen in TB, diphtheritic myocarditis, PAN.
 
Pulse-respiration Ratio
With every 1°F rise in temperature there is increase in respiratory rate by 2–3 / min.
  • Normal – 4:1 (72:18)
  • Increase – 12:1 (72:6) seen in narcotic poisoning.
  • Decrease – 2:1 (72:36) seen in acute lobar pneumonia.
 
Drug Induced Hyperthermia
Seen in – MAO inhibitors, TCAs, Amphetamines.
 
Malignant Hyperthermia
Inherited abnormality of skeletal muscles.
Pathology: Increased intracellular Ca++ level due to release from sarcoplasmic reticulum leads to muscle contraction.
Precipitated by: Halothane, Succinylcholine.9
Features: Increased temperature, muscle contraction – rigidity, rhabdomyolysis, acidosis.
Treatment: External cooling.
O2 inhalation, bicarbonate infusion, IV dantrolene.
Investigation: Increased serum CPK.
 
Neuroleptic Malignant Syndrome
Caused by: Chlorpromazine, Haloperidol.
Characterized by: Hyperthermia, muscle rigidity, tremor, semi-consciousness, fluctuating BP and heart rate.
Treatment: IV dantrolene, bromocriptine.
 
Heatstroke
Complications: DIC, shock, hyperkalemia, hypocalcemia, cerebellar degeneration.
 
HYPOTHERMIA
Core temperature ≤ 35°C
Risk factors: Extremes of age, ethanol use, Malnutrition, Hypothyroidism.
Effects: Hypotension, bradycardia. Early tachypnea followed by hypoventilation.
ECG – QT prolongation, Osborn (J) wave,
Lactic acidosis, hypoactivity, hyperglycemia.
Complications: Atrial arrhythmias.
Treatment:
Re-warming – Which should not be prompt.
Methods – Extracorporeal blood warming by hemodialysis or cardiopulmonary bypass – best method.
IV warmed NS.
 
Neonatal Hypothermia
Signs: Bradycardia, sclerema, metabolic acidosis.
Treatment: Convection warmed incubators.10
NERVOUS SYSTEM DYSFUNCTION
 
SYNCOPE
 
Causes
  1. Decreased cerebral blood flow:
    1. Vasovagal.
    2. Postural or orthostatic.
    3. Carotid sinus syncope.
  2. Decreased venous return:
    1. Valsalva maneuver.
    2. Cough.
    3. Micturition.
  3. Decreased cardiac output:
    1. Cardiac tamponade.
    2. Aortic stenosis.
  4. Arrhythmias: Second and third degree AV block with Stokes - Adams syndrome.
  5. Congenital heart disease: Tetralogy of Fallot.
 
Treatment
  1. Vasovagal syncope with normal LV systolic functions– β-blockers, Disopyramide, Theophylline, Scopolamine and ephedrine.
  2. Postural syncope:
    Postganglionic type: Salt loading, Fludrocortisone.
    Preganglionic type: Tyramine, MAO inhibitors.
  3. Carotid sinus syncope – Atropine or ephedrine.
 
VERTIGO
The most common cause of pathologic vertigo is vestibular dysfunction.
 
Ménière's Disease
It is the most common cause of otogenic vertigo.
Pathology: Hydrops or distension of the endolymphatic system.
Clinical feature: Age group affected - 30–50 years.
Unilateral symptoms.11
Episodic attacks of:
Rotatory vertigo, fluctuating deafness (sensorineural), tinnitus, fullness in ear.
Investigation: Audiometry – Sensorineural deafness more in lower frequency (Cochlear).
Recruitment tests - +ve on the affected side.
Treatment:
  1. Nicotinic acid – (Vasodilator) – increases endolymphatic reabsorption.
  2. Surgery – Cody tack operation.
WEAKNESS
 
PHYSIOLOGY OF MOTOR SYSTEM
 
Higher Center
The following parts of brain are involved in motor activities:
  1. Cerebral cortex – highest center.
    Motor cortex – in the precentral gyrus (Brodmann area 4).
    Premotor cortex – posterior ends of inferior, middle and superior frontal gyri (Brodmann area 6 and 8).
    Supplementary motor area – on medial surface of brain.
    Note: In motor cortex, various parts of the body are represented in an inverted manner. Only the facial area is represented bilaterally. All other areas are unilateral, controlling movements of the opposite side.
  2. zoom view
  3. Basal ganglia – Planning and programming of movements.
 
Descending Tracts
  1. Pyramidal tracts: They arise from cerebral cortex and end either on motor neurons in spinal cord or cranial nerve nuclei in brainstem.12
    1. Corticospinal tract:
      1. Lateral corticospinal tract – produces an elevation (pyramid) in midbrain. They comprise about 80 percent fibers of pyramidal system. They descend through the internal capsule, cross midline at cervico- medullary junction and end on lateral neurons in the ventral horn of spinal cord (on opposite side).
        Action – concerned with distal limb muscle and with skilled movements (of opposite side).
      2. Ventral corticospinal tract – 20 percent fibers that do not cross the midline until at the level where they synapse with motor neurons. They end primarily on interneurons (on the same side) which cross the midline and end on medial neurons in the ventral horn of spinal cord.
        Action – control axial and proximal limb muscles.
    2. Corticobulbar tract: From cerebral cortex to cranial nerve nuclei in the brainstem (usually on the opposite side). Some fibers end bilaterally e.g. those for muscles of mastication and upper half of face.
      Note: Locations of cranial nerve nuclei –
      Midbrain – 3 and 4.
      Pons – 5, 6, 7 and 8.
      Medulla – 9, 10, 11 and 12.
  2. Extrapyramidal (Bulbospinal tracts):
    1. Ventromedial bulbospinal tracts:
      1. Tectospinal – originate from tectum in midbrain.
      2. Vestibulospinal – from the lateral and medial vestibular nuclei.
      3. Reticulospinal – from the reticular formation.
        Action – Influence axial and proximal muscles and are involved in maintenance of posture and integrated movements of limbs and trunk.
    2. Ventrolateral bulbospinal tract:
      Rubrospinal –from magnocellular portion of red nucleus.
      Action – facilitate distal limb muscles.
 
UMN vs LMN
Upper motor neuron (UMN) – neurons that contribute to pyramidal tract (Corticospinal + Corticobulbar).13
Lower motor neuron (LMN) – Anterior horn cells and related cranial motor nuclei and their axons.
Difference between UMN lesion and LMN lesions
Sign
UMN lesion
LMN lesion
1.
Atrophy
−
+
2.
Fasciculation
−
+
3.
Tone
Spastic
Flaccid
4.
Tendon reflexes
Hyperactive
Hypoactive/absent
5.
Babinski's sign
+
−
Note: In Friedrich's ataxia, Babinski's sign is +ve (UMN lesion) but deep tendon reflexes are absent (LMN type).
 
PATHOLOGY OF MOTOR SYSTEM
 
Hypertonia
 
Causes
  1. UMN lesion (‘clasp – knife’ spasticity)
  2. Extrapyramidal lesion except chorea (lead pipe or cogwheel rigidity) – e.g. Parkinsonism.
  3. Tetanus.
  4. Tetany – hypocalcemia.
  5. Strychnine poisoning.
 
Types
  • Spasticity – in pyramidal (UMN) lesion.
  • Rigidity – in extrapyramidal lesion.
  • Paratonia or Gegenhatten – in frontal lobe lesion.
 
Hypotonia (Flaccidity)
 
Causes
  1. LMN lesion.
  2. Tabes dorsalis (Posterior column lesion)
  3. Chorea
  4. Cerebellar lesion.
  5. Myopathy.
  6. Hypokalemia or hypercalcemia.
  7. Others – Down's syndrome, Rickets.
    14
 
CLINICAL
 
Hemiplegia
Due to UMN lesion above the midcervical spinal cord.
Most common cause – Thrombosis of lenticulostriate branch of middle cerebral artery.
Investigation: CT scan, MRI.
 
Crossed Hemiplegia
Due to brainstem lesion.
E.g. – Weber's syndrome – Ipsilateral third nerve palsy (LMN type) with contralateral hemiplegia, due to midbrain (mesencephalon) lesion.
 
Paraplegia
Due to intraspinal lesions at or below the upper thoracic spinal cord level.
 
Cause
  1. Spastic paraplegia (UMN type):
    1. Cord compression – most commonly due to carries spine.
    2. Motor neuron disease.
    3. Multiple sclerosis.
    4. Acute transverse myelitis.
    5. Friedrich's ataxia.
    6. Syringomyelia.
    7. Lathyrism.
    8. Cervical spondylosis.
  2. Flaccid paraplegia (LMN type):
    1. Poliomyelitis.
    2. GB syndrome.
    3. Progressive muscular atrophy.
    4. Myasthenia gravis.
    5. Myopathy.
 
Traumatic Paraplegia
Most common cause of paraplegia is trauma.
Site: Most common site of spinal injury is dorsolumbar spine.15
Note: Lesion above C5 is fatal due to respiratory failure. Lesion at C5-C6 level produces quadriplegia.
Clinical feature: Flaccid paraplegia in spinal shock stage. Spastic paraplegia later on. Often with bladder involvement.
Investigation: MRI is the method of choice.
Complications: Negative nitrogen balance, decubitus ulcer, hypercalcemia leads to calcium stones.
UTI – most common complication.
Treatment
  1. High dose corticosteroid as early as possible.
  2. Bladder care – Intermittent catheterization is best.
 
Monoplegia
Todd's paralysis – in epilepsy.
Note: Descending motor paralysis is caused by – Diphtheria, botulinum toxin and polio.
 
MOVEMENT DISORDERS
 
Tremor
Rest tremor – Parkinsonism.
Postural tremor – Hyperthyroidism.
Intention tremor – Cerebellar disease.
Flapping tremor/Asterixis – Hepatic failure (precoma), uremia, respiratory failure, CO2 narcosis, renal failure.
 
Hemiballismus
Sudden flinging movement of limbs.
Cause: Infarction of the contralateral subthalamic nucleus of basal ganglia.
 
Chorea
Rapid, jerky, irregular quasipurposive movement of basal ganglia.
Cause: Lesion in caudate nucleus.
  • Sydenham's chorea – Rheumatic fever.
  • Huntington's Chorea – most common type.
  • Levodopa toxicity – most common cause of chorea.
    16
Features: Hypotonia, pronator sign, milking sign, spooning sign, hung up reflex, lizard tongue.
 
Athetosis
Lesion in Lentiform nucleus (Globus pallidus).
Note: Basal ganglia lesions produce –
Hyperkinetic movements - chorea, athetosis and ballism.
Hypokinetic movements – Akinesia and bradykinesia.
 
Myoclonus
Cause: Lipid storage disease, Encephalitis (SSPE), Creutzfeldt-Jakob disease, Metabolic encephalopathies. Electrolyte imbalance.
BALANCE AND GAIT
 
Control
  1. Head position in space – Controlled by inner ear.
    The utricle and saccule – sense static head position and acceleration (linear).
    The semicircular canals – sense rotatory motions (angular acceleration).
    Impulses pass though vestibular nerve to the vestibular nuclei in the lower pons and upper medulla.
  2. Head position relative to body: Receptors for joint position, joint movement and muscle stretch. Impulses are transmitted via posterior column and medial lemniscal pathways to the cerebrum and the spinocerebellar pathways to the cerebellum.
 
Ataxia
It is defined as clumsiness of movement without sensory or motor disturbance.
Types:
  1. Cerebellar ataxia.
  2. Sensory ataxia – due to involvement of:
    1. Peripheral sensory nerves, e.g. peripheral neuropathy.
    2. Posterior nerve root – Tabes dorsalis.
      17
    3. Posterior column – Multiple sclerosis, syringomyelia.
    4. Diseases of parietal lobe.
      Test – Positive Romberg sing.
  3. Vestibular ataxia – often with vertigo.
Note: Fenkel's exercise is done in a case of ataxia (e.g. Tabes dorsalis).
 
Abnormal Gait
  1. Hemiparetic gait – in cerebral stroke.
  2. Paraparetic or scissoring gait – in spinal cord disease
  3. Stamping gait – in sensory ataxia, classically in Tabes dorsalis.
  4. Steppage or Equine gait – in common peroneal nerve palsy (with foot drop). (Anterior tibial nerve injury).
  5. Festinant gait – Parkinsonism.
  6. Waddling gait – Myopathy.
  7. Drunker or ataxic gait – Cerebellar ataxia or acute alcohol intoxication.
  8. Apraxic gait – in bilateral frontal lobe disease.
  9. Astasia – abasia – hysterical gait disorders.
 
Signs of Cerebellar Disease
  1. Hypotonia.
  2. Scanning speech.
  3. Intention tremor.
  4. Pendular knee jerk.
  5. Dysmetria.
  6. Ataxia.
  7. Decomposition of movements.
  8. Dysdiadochokinesia.
  9. Rebound phenomenon.
  10. Drunken or ataxic gait.
  11. Titubation.
EPISODIC DISORDERS
 
Abnormal Facial Movements
  1. Hemifacial spasm – Often involves the muscles around eyes and caused by paroxysmal facial nerve activity.
    18
  2. Facial tics – Gilles de la Tourette syndrome.
  3. Synkinesis, e.g. jaw winking in Bell's palsy (after recovery).
  4. Tic douloureux – trigeminal neuralgia.
 
Abnormal Limb Movements
  1. Fasciculation – in motor neuron disease.
  2. Akathisia – Parkinsonism.
  3. Restless leg syndrome – uremia and other neuropathies (in middle aged females).
  4. Startle syndrome or hyper-reflexias – result from mutations in glycine receptors.
 
Muscle Disorders
  1. Myotonia – Myotonic dystrophy.
    Myotonia congenita – AD or AR inheritance. Due to defective Cl− channel.
  2. Paramyalgia Rheumatic –
Clinical feature: Stiffness and pain in shoulder and hip in patients over age 50.
Muscle biopsy shows: muscle atrophy, CPK level is normal.
Treatment: NSAIDs and prednisolone.
 
Episodic Weakness
Causes:
  1. Hype/hyperkalemia.
  2. Hypo/hypercalcemia.
  3. Hyponatremia.
  4. Hypophosphatemia.
  5. Hypomagnesemia.
  6. Myasthenia gravis and Lambert–Eaton syndrome.
SPEECH
 
PHYSIOLOGY
Language is a function of the dominant or categorical hemisphere that is the left hemisphere in right handed persons (Perisylvian region).19
Areas:
  1. Wernicke's area (Area 22) -
    Location – posterior third of superior temporal gyrus.
    Action – Comprehension of auditory and visual information.
  2. Broca's area (Area 44) -
    Location – Posterior part of inferior frontal gyrus.
    Function – Speech production.
    The above two areas are connected by arcuate fasciculus.
    Blood supply – by middle cerebral artery.
 
APHASIA
 
Wernicke's Aphasia (Sensory Aphasia)
Comprehension is impaired but fluency is normal or increased.
There is paraphasia, neologism – ‘Jargon speech’.
Cause: occlusion of inferior division of middle cerebral artery.
 
Broca's Aphasia (Motor Aphasia)
Comprehension is preserved but fluency is decreased.
Others: Word finding pause (telegraphic speech).
Cause: Occlusion of superior division of the middle cerebral artery.
 
Global Aphasia
Involvement of both Wernicke's and Broca's areas.
Cause: Occlusion of entire middle cerebral artery (cerebral stroke).
Prognosis: Worst.
Crossed aphasia: right hemispherical lesion in right handed person.
 
Conduction Aphasia
Comprehension and fluency are preserved, but repetition and naming are impaired.20
Cause – Lesion in arcuate fasciculus. Lesions of auditory cortex (area 40, 41, 42).
 
Anomic Aphasia
Only naming is impaired. There is difficulty in understating written language.
Cause: Lesions in angular gyrus.
Characteristically seen in – head trauma, metabolic encephalopathy, Alzheimer's disease.
 
Pure Word Deafness
Cause: Bilateral or left sided superior temporal gyrus lesion.
 
Alexia
Cause: Occlusion of posterior cerebral artery.
Note: Scanning speech is seen in disseminated sclerosis.
 
APRAXIA
It is a disorder of initiating and planning movement.
Cause: Right sided apraxia is caused by lesion of left frontal lobe, or the left temporoparietal region (especially the supramarginal gyrus).
Type: Ideomotor apraxia – most common type.
 
Gerstmann's Syndrome
Acalculia, dysgraphia, finger anomia and right-left confusion.
Cause: Damage of inferior parietal lobe (angular gyrus) of left hemisphere.
 
Balint's Syndrome
Spatial disorientation caused by – Oculomotor apraxia, optic ataxia and simultanagnosia.
Cause: bilateral lesion in parietal lobe.
 
Dressing Apraxia
Cause: Bilateral or right sided (non-dominant) dorsal parietal lobe lesion (also construction apraxia).21
 
Prosopagnosia
Inability to recognize face.
Cause: Bilateral lesion in fusiform and lingual gyri of occipitotemporal cortex.
SENSORY SYSTEM
 
PHYSIOLOGY
 
Receptors
zoom view
 
Pathways
Fibers: Aβ (large myelinated) – fine touch and pressure.
Aδ (small myelinated) – Temperature and pain.
C (small unmyelinated) – Pain and temperature.
Tracts: Touch – Ventral spinothalamic tract.
Pain and temperature – Lateral spinothalamic tract.
Touch and proprioception – Dorsal column / Lemniscal system.
Spinothalamic tracts:
zoom view
22
Lemniscal system:
zoom view
 
Higher Centers
Somatic sensory area I – Post-central gyrus in parietal cortex (Brodmann area 1, 2, 3).
Somatic sensory area II – in the wall of the Sylvian fissure in parietal cortex.
 
Cortical Sensations
  1. Two-point discrimination.
  2. Touch localization.
  3. Graphesthesia.
  4. Stereognosis – lost in parietal cortex lesion.
zoom view
 
PATHOLOGY
 
Sensory Neuropathies
Causes:
  1. Diabetes.
  2. Beriberi.
  3. Leprosy.
  4. Alcohol.
  5. Vitamin B12 deficiency.
 
Dissociated Sensory Loss
Pain and temperature sensations are lost but touch is spared.
Cause: Syringomyelia.
Note: Balaclave helmet type of sensory loss over face is seen in syringomyelia.23
ALERTNESS, CONFUSION AND COMA
 
PHYSIOLOGY
 
Reticular Activating System
Wakefulness – alertness is maintained my RAS.
Location – Midventral portion of the medulla and midbrain (reticular formation) + thalamus.
Brainstem RAS neurons project to thalamic relay nuclei which in turn projects to neocortex.
Note: The reticular formation contains motor, sensory, autonomic, all types of fibers.
 
Brainstem Reflexes
  1. Papillary reaction to light.
  2. Spontaneous eye movement.
  3. Oculocephalic reflex or ‘Doll's – eye’
  4. Oculovestibular reflex.
  5. Corneal reflex.
Note: Normal cerebral blood flow (CBF) is 75 ml/100 g/min in gray matter and 30 ml/100 g/min in white matter (mean 55 ml/100 g/min).
CBF < 10 ml/100g/min produce irreversible brain damage.
Normal O2 consumption of brain 3.5 ml/100 g/min.
 
PATHOLOGY
Three major groups of lesions produce confusion and coma:
  1. Supratentorial mass – e.g. cerebral hemorrhage or cerebral tumor.
  2. Infratentorial lesion.
  3. Metabolic disorders like hypoxia, hypercapnia, hyponatremia, hyperosmolarity, hypercalcemia, hypoglycemia and metabolic encephalopathies (hepatic, renal, respiratory failures).
Supratentorial lesions produce secondary compression of brainstem due to transtentorial herniation.24
 
CLINICAL
 
Signs of Brain Death
Three essential elements:
  1. Widespread cortical destruction shown by deep coma– Isoelectric EEG.
  2. Brainstem damage – absent pupillary light reaction, oculovestibular and corneal reflexes.
  3. Medullary destruction – Complete apnea.
Others:
  1. No Gag reflex.
  2. No motor response.
  3. Pulse – invariant and unresponsive to atropine.
Note: If respiration is maintained artificially heart, kidneys and liver may continue to function normally. But after brainstem death has occurred, cardiac arrest will follow within 2 weeks.
Diagnosis:
  1. Blood – Ethanol level > 200 mg/dl causes confusion and impaired mental activity. Level > 300 mg/dl causes stupor.
  2. CT scan and MRI
  3. EEG –
    ‘Alpha coma’ (widespread 8–12 Hz activity)-
    Caused by high pontine diffuse cortical damage and associated with a poor prognosis.
    ‘Beta coma’ (Fast activity) – Sedatives.
    ‘Delta coma’ (High voltage slow waves in frontal region) – Metabolic encephalopathy.
  4. CSF study.
Differential diagnosis:
  1. Pontine hemorrhage – Fever, pin – point pupils, ocular bobbing (diagnostic), hyperventilation, sweating, pseudocoma.
  2. Cerebellar hemorrhage – Occipital headache, vomiting, gaze paresis, inability to stand.
  3. Metabolic encephalopathy – Asterixis or flapping tremor, most characteristic sign.
    25
MEMORY
 
PHYSIOLOGY
  1. Short-term memory:
    1. Recent memory – concerned with hippocampus and perihippocampal portion of medial temporal cortex.
    2. Immediate memory – Perisylvian cortex, frontal lobe.
  2. Long-term memory – Association cortex.
 
AMNESIA
 
Types
  1. Retrograde amnesia – Inability to recall events preceding the amnesic state (recent memory loss). Long-term memory is intact.
    Causes – Cerebral concussion, Electroconvulsive therapy.
  2. Anterograde amnesia – Inability to store, retain and recall new knowledge.
    Cause – Bilateral medial temporal lobe lesion.
Other causes of short-term memory loss:
  1. Brain tumor.
  2. Brain infarction.
  3. H–S encephalitis.
  4. Chronic alcoholism.
  5. Degenerative dementias – Alzheimer's disease and Pick's disease.
 
Frontal Lobe Syndrome
  1. Abulia – Due to damage to dorsolateral prefrontal cortex. E.g. – tumor.
  2. Disinhibition – damage to medial prefrontal or orbitofrontal cortex.
  3. Confabulation – Lesion of ventromedial portion of frontal lobe.
Note: Personality change is seen in frontal lobe lesion. Glabellar or palmomental reflexes are represented at frontal lobe.26
 
DEMENTIA
Loss of cognitive function (mainly memory) with clear conscience.
Most important risk factor is increasing age.
 
Causes
  1. Cortical dementia:
    1. Alzheimer's disease.
    2. Pick's disease.
  2. Subcortical dementia:
    1. Huntington's chorea.
    2. Parkinsonism.
    3. Wilson's disease.
  3. Vitamin deficiencies:
    1. Thiamine (B1): (Wernicke's encephalopathy) most commonly due to chronic alcoholism.
    2. Vitamin B12 (pernicious anemia).
    3. Nicotinic acid (B3) – Pellagra.
  4. Endocrinal – Hypothyroidism, Hypo/Hyperpara-thyroidism.
  5. Pseudodementia – Depression.
  6. Head trauma – ‘Punch drunk’ syndrome or dementia puglistica in Parkinsonism. Normal pressure hydrocephalous.
  7. Infections-
    Prion (Creutzfeldt-Jakob disease)
    HIV (AIDS – dementia complex)
  8. Toxic – Dialysis dementia due to aluminium.
 
Features
 
Lesion in Frontal Lobe
Personality change, impaired memory, anosmia, urinary incontinence, antisocial behavior.
 
Parietal Lobe
  1. Dominant lobe: Aphasia, acalculia (Gerstmann's syndrome), ideomotor apraxia, agnosia.
  2. Nondominant lobe: Construction and dressing apraxia, spatial disorientation, neglect of non-dominant side.
  3. Bilateral: Balint's syndrome, homonymous hemianopia.
    27
 
Temporal Lobe
Poor memory, complex hallucinations, homonymous hemianopia.
Others – Aphasia, dyslexia, loss of musical skill.
 
Occipital Lobe
Prosopagnosia, visual agnosia, visual hallucinations, homonymous hemianopia, hemianopic scotoma.
EYE AND VISION
 
PHYSIOLOGY
 
Retina
Macula lutea: Yellowish pigmented spot near the posterior pole, contains the pigment xanthophyll. Responsible for central 10° vision.
Fovea centralis – It the small pit in the center of macula. It contains only cones. Area of maximum visual acuity.
Optic disc – Lies 3 mm medial to posterior pole. Optic nerve leaves the eye and blood vessels enter at this point. Contains no visual pigment – ‘blind spot’.
 
Visual Pigments
  1. Rods: Operative under dim light (scotopic vision).
    Contain – The pigment rhodopsin which is made up of protein called opsin and an aldehyde called 11–cis retinal (vitamin A).
    On exposure to light 11–cis retinal is converted to all-trans retinal and vice versa.
    There are 100 million roads in human retina.
  2. Cones: Operative under bright light (photopic vision). Also responsible for color vision.
Cones contain pigments (idopsin) which respond maximally to wavelengths 450, 535 and 565 nm (red, green and blue vision).
There are 5 million cones in retina, maximum in macula.28
 
Ocular Reflexes
  1. Light reflex: Constriction of pupil on exposure to light (direct and consensual).
    This is mediated by constrictor muscle of iris (sphincter pupillae) which is supplied by parasympathetic nerve via oculomotor nerve.
    Pathway – See later.
  2. Accommodation reflex: Increase in curvature (of the anterior surface) of lens on looking at a near object.
    It is due to contraction of ciliary muscles and relaxation of lens ligaments.
  3. Near reflex: Constriction of pupil on looking at a near object.
    It is mainly initiated by medial rectus muscle which converges eyeballs on looking at a near object.
Note:
Near response: consists of:
  1. Accommodation.
  2. Convergence of visual axes.
  3. Pupillary constriction.
  4. Corneal reflex: Absent in CP angle tumors, mediated by trigeminal nerve.
 
PATHWAYS
 
Visual Pathway
Pigment epithelium in retina → Bipolar cell with its axons (1st order neuron) → Ganglion cells (2nd order neuron) → Optic nerve → Crosses midline at optic chiasma (only nasal fibers) → (Optic tract) Lateral geniculate body → (Optic radiation) Visual cortex (Brodmann area 17) in Occipital cortex around calcarine sulcus.
Note: Visual cortex is supplied by posterior and middle cerebral arteries.
 
Light Reflex
Same as visual pathway up to optic chiasma → pre-tectal nuclei in midbrain → EW nuclei on both sides → parasympathetic output via oculomotor nerve through ciliary ganglion → sphincter of the iris.
Note: No LGB in light reflex pathway.29
 
PUPILLARY DEFECTS
 
Hippus
Alternate dilatation and contraction of pupil.
Seen in – multiple sclerosis.
 
Argyll Robertson Pupil (ARP)
Features:
  1. Absence of light reaction
  2. Presence of accommodation reflex.
  3. Miosis, irregular pupil
  4. Normal VA and optic disc
  5. No response to mydriatics.
    (Mnemonic: ARP – accommodation reflex present).
Cause:
Lesion between pretectal nuclei and EW nuclei (Internuncial neurons).
  1. Neurosyphilis
  2. Obstructive hydrocephalus
  3. Pineal region tumors
  4. Others – Diabetes, syringomyelia, multiple sclerosis, chronic alcoholism.
 
Marcus-Gunn Pupil
Or relative afferent pupillary defect (RAPD).
Feature: Direct light response is less than consensual light reflex.
Test: Swinging – flash light test.
Cause: Retrobulbar optic neuritis (most common).
 
Adie's Tonic Pupil
Unilateral dilated pupil with poor light reaction and slow redilatation after removal of near object.
Cause: Idiopathic (most common).
Diagnosis: 0.125 percent pilocarpine test – tonic pupil constricts rapidly.30
 
Miosis
Horner's syndrome:
  1. Miosis.
  2. Pseudoptosis (due to paralysis of Müller's muscle supplied by cervical sympathetic nerve).
  3. Enophthalmos.
  4. Anhydrosis.
Cause:
  1. Idiopathic – most common.
  2. Squamous cell Ca of lung.
  3. Brainstem stroke.
  4. Carotid dissection.
 
Mydriasis
  1. Oculomotor nerve palsy.
  2. Injury to ciliary ganglion due to infections, trauma, diabetes, temporal arteritis.
  3. Hutchinson's pupil – fixed dilated pupil in subdural hemorrhage.
Note:
In optic disc glioma – Direct reflex is absent but consensual reflex is present (in any optic nerve lesion).
In cortical blindness (bilateral occipital lobe lesion) – both direct and consensual reflexes are present in both eyes.
 
COLOR VISION
Red, green and blue are primary colors.
 
Theories of Color Vision
The Young-Helmholtz theory – postulates the presence of 3 different types of cones for 3 primary colors.
 
Color Blindness
 
Congenital
Nomenclature:
  • Anomaly = weakness
  • Anopia = blindness
  • ‘Prot’ = Red
  • ‘Deuter’ = Green
  • ‘Tri’ = Blue
    31
Cause:
  • Gene for blue cone is located on chromosome 7.
  • Genes for red and green are located on the long arm of X chromosome.
  • Mutations of these genes produce congenital color blindness.
  • Mutation of blue cone gene is extremely rare. Hence, most of the cases are transmitted as X-linked recessive and manifest in males.
Type:
  • Most common type is deuteranopia.
Diagnosis:
  • Ishihara's chart for red-green vision.
  • Negel's anamaloscope.
 
Secondary
Causes:
  1. Optic neuritis/macular disease.
  2. Bilateral occipital lobe lesion (area V8) –
    Cerebral achromatopsia – color blindness,
    decrease VA, nystagmus, prosopagnosia.
  3. Lesion in dominant occipital lobe – color anomia.
  4. Drugs – Ethambutol, Sildenafil (Viagra).
 
VISUAL FIELD
Normal visual field
  • It is 60° above and nasally (minimum)
  • 70-75° below and
  • 100-110° temporal (maximum) to fixation point (fovea).
    Test – Perimetry.
 
VISUAL FIELD DEFECTS (SCOTOMA)
 
Glaucoma
Selectively destroys the arcuate fibers.
  1. Isopter contraction – first change.
  2. Isolated paracentral scotoma – earliest field defect.
  3. Seidel's scotoma
  4. Arcuate (Bjerrum's) scotoma - most characteristic32
    Also seen in – Optic neuritis, ischemic optic neuropathy, optic disc drusen and BRAO.
    When both superior and inferior arcuate fibers are involved it produces a ring around macula, called ring scotoma.
  5. Roenne's nasal step
  6. Double arcuate scotoma – last field defect, produces tubular vision.
 
Altitudinal Hemianopia
Due to damage to entire upper or lower pole of optic disc.
Causes:
  1. Anterior ischemic optic neuropathy (AION) - most common cause.
    Due to occlusion of short posterior ciliary arteries, most commonly due to atherosclerosis.
    Produces – sudden visual loss with inferior hemianopia.
  2. Retinal vascular occlusion
  3. Advanced glaucoma
  4. Optic neuritis.
 
Ceco-central Scotoma
Due to damage to papillomacular fibers – produces temporal pallor.
Cause:
  1. Optic neuritis – most common cause
  2. Nutritional optic neuropathy – due to deficiency of thiamine (Vitamin B1) in heavy drinkers and pipe- smokers.
  3. Toxic amblyopic – due to methyl alcohol, may produce total optic atrophy. Also by Ethambutol.
  4. Leber's hereditary optic neuropathy.
 
Scintillating Scotoma
Seen in migraine.
 
Ring Scotoma
Retinitis pigmentosa.33
 
Damage to Visual Pathways
  1. Tumors anterior to optic chiasm – Junctional scotoma.
    Cause – Meningioma of tuberculum sella.
  2. Compression of optic chiasm – Bitemporal hemianopia.
    Cause – Pituitary adenoma, meningioma, craniopharyngioma, glioma, aneurysms.
  3. Injury to post-chiasmal pathway, i.e. optic tract, LGB, optic radiation and occipital cortex – produces homonymous hemianopia.
  4. Damage to optic radiation in temporal lobe (Meyer's loop) – Superior quadrantopia.
  5. Damage to optic radiation in parietal lobe – inferior quadrantopia.
  6. Lesion in occipital lobe due to occlusion of posterior cerebral artery – produces homonymous hemianopia with macular sparing because tip of macula is supplied by middle cerebral artery.
 
SYMPTOMATOLOGY
 
Painful Red Eye
  1. Conjunctivitis – most common cause
  2. Blepharitis
  3. Keratitis
  4. Uveitis
  5. Acute angle-closure glaucoma
  6. Endophthalmitis.
 
Sudden Visual Loss
  1. Transient or amaurosis fugax – Central retinal artery occlusion – most commonly due to emboli (cholesterol emboli called Hollenhorst plaque) from atherosclerotic plaque in carotid artery. Also seen in papilledema.
  2. Branch or central retinal vein occlusion.
  3. Anterior ischemic optic neuropathy (AION).
  4. Optic neuritis – painful.
  5. Leber's optic atrophy.
  6. Toxic amblyopia.
  7. Optic disc drusen.
  8. Vitreous degeneration/hemorrhage/opacity.
    34
  9. Retinal detachment.
  10. Classic migraine.
  11. Hypertensive retinopathy.
 
Chronic Loss of Vision
  1. Cataract.
  2. Glaucoma.
  3. Age-related macular degeneration.
  4. Central serous retinopathy.
  5. Diabetic retinopathy.
  6. Retinitis pigmentosa.
  7. Melanoma of choroid.
 
Proptosis
Measured by Hertel exophthalmometer.
  1. Grave's ophthalmoplegia – most commonly involves the medial and inferior recti.
  2. Orbital pseudotumor.
  3. Tumors of orbit – most commonly hemangioma.
  4. Carotid cavernous fistula – pulsating proptosis.
 
Ptosis
  1. Myogenic: Lid-lag on ptosis side on down gaze.
    1. Myasthenia gravis – fluctuating ptosis that worsens late in day.
    2. Kearns-Sayre syndrome – ptosis, retinitis pigmentosa and heart block.
  2. Neurogenic:
    1. Horner's syndrome (pseudoptosis) – due to paralysis of Müller's muscle – pupils are miotic.
    2. Oculomotor nerve palsy – pupils are larger or normal.
Test: Tensilon test
Treatment:
  1. Fasanella–Servat operation for Horner's syndrome.
  2. Blaskowics' levator resection.
 
Nystagmus
  1. Optokinetic or jerk nystagmus – physiological nystagmus.
    35
  2. Congenital nystagmus – Pendular or sinusoidal due to blindness from anterior visual pathway disease early in life.
  3. Gaze evoked – most common type of jerk nystagmus.
    Exaggerated by – myasthenia, brainstem lesion, cerebellar lesion.
  4. Vestibular nystagmus – Ménière's disease.
  5. Downbeat nystagmus – Lesions near craniocervical junction (e.g. Chiari malformation, posterior fossa tumor).
  6. Upbeat nystagmus – Phenytoin toxicity, stroke, posterior fossa tumors.
  7. See-saw nystagmus – Chiasmal lesion (e.g. craniopharyngioma).
  8. Ataxic (gaze-paretic) nystagmus –also called internuclear ophthalmoplegia due to damage of medical longitudinal fasciculus.
  9. Opsoclonus – bursts of consecutive saccades (saccadonia) seen in viral hepatitis.
  10. Ocular flutter – seen in neuroblastoma.
  11. Rotatory nystagmus – seen in miners.
SMELL
 
PHYSIOLOGY
Olfactory receptor cells: Bipolar cells located in the olfactory neuroepithelium in the superior 1/3rd of nasal mucosa. Each bipolar cell has a short, thick dendrite with an expanded end called an olfactory rod. It bears 6-8 cilia which contain the odorant receptors.
Two characteristic of olfactory cells are that:
  1. They are regularly replaced by new cells.
  2. They regenerate after injury.
Other cells in olfactory neuroepithelium are microvillar cells, sustentacular cells and basal cells.
 
Olfactory Pathways
Olfactory receptor cells → axons pierce cribriform plate → Olfactory glomeruli in olfactory bulb → Mitral and tufted cells (2nd order neurons) → Olfactory cortex.
Note: Olfactory sensation is not relayed by thalamus.36
 
Olfactory Cortex
  1. Piriform cortex
  2. Orbitofrontal gyri in frontal lobe
  3. Amygdala (emotional response to smell).
  4. Entorhinal cortex (olfactory memory).
 
PATHOLOGY
 
Anosmia
Causes:
  1. Head trauma – most common cause in children and young adults.
  2. Viral infections – most common cause in older adults.
  3. Congenital anomaly – Kallmann's syndrome – Anosmia and hypogonadotrophic hypogonadism.
  4. Neoplasm – Meningioma of frontal lobe (most common).
  5. Nutritional deficiencies of –
    1. Vitamin A
    2. Vitamin B12
    3. Zn
    Note: Hallucination of bad smell – Temporal lobe lesion Parosmia – Perception of bad smell.
TASTE
 
PHYSIOLOGY
 
Taste Buds
Are test receptor cells.
Types with locations:
  1. Fungiform papillae – On the dorsum of tongue, most numerous at the tip.
  2. Foliate papillae – along the lateral margins.
  3. Vallate papillae – back of tongue.
Other locations:
Palate, epiglottis, larynx and esophagus.37
 
Taste Pathways
Fibers carrying taste sensation:
  1. From anterior 2/3 of tongue: Chorda tympani nerve.
  2. From posterior 1/3 including vallate papillae: Glossopharyngeal nerve.
  3. Vagus nerve – from other sites.
They synapse on NTS in medulla → 2nd order neurons cross midline and project to the thalamus along with fibers in medial lemniscus → 3rd order neurons project to taste projection area in the cerebral cortex at the foot of the postcentral gyrus.
 
Taste Modalities
  1. Sweet – Organic substances
  2. Salt – Due to Na+
  3. Sour – due to H+
  4. Bitter – Due to cations.
Taste buds for above modalities are located in the tongue from anterior to posterior (tip to base) in the above order, i.e. sweet at the tip and bitter at the base.
 
PATHOLOGY
 
Hypogeusia
Diminished taste sensation is cause by captopril.
HEARING
 
ANATOMY AND PHYSIOLOGY
 
Inner Ear
It consists of two parts:
  1. Cochlea – involved in hearing.
  2. Semicircular canal – involved in equilibrium (see above).
Structurally, it has two parts – the bony labyrinth outside and membranous labyrinth inside separated by perilymph.38
 
Cochlea
It has 2 and ¾ turns.
It has 3 parts on cross-section:
  1. Scala vestibuli – above Reissner's membrane, filled with perilymph and connects laterally with the oval window.
  2. Scala tympani – below basilar membrane, filled with perilymph and connects to the round window.
    The above two are connected through helicotrema.
  3. Scala media – part between the above two, filled with endolymph, and contains the organ of Corti. This is also called the cochlear duct.
 
Organ of Corti
  • Located on the basilar membrane in the cochlear duct.
  • Contains hair cells which are the auditory receptors.
  • Afferent neurons innervate the inner hair cells and efferent neurons the outer hair cells.
  • Axons of afferent neurons form the cochlear division of the VIII cranial nerve.
 
Fluids
  1. Perilymph – occupies the area between bony and membranous labyrinth (perilymphatic space) and scala vestibuli and scala tympani. It contains high levels of Na+ and low K+.
  2. Endolymph – occupies the membranous labyrinth (scala media) and contains high K+ and low Na+.
 
Auditory Pathway
zoom view
39
Auditory cortex – situated in the superior part of temporal cortex in the Sylvian fissure (Brodmann area 41).
 
TESTS OF HEARING
 
Rinne's Test
Using a 256 Hz tuning fork.
It compares air conduction (AC) with bone conduction (BC).
In normal ear, AC > BC – positive Rinne.
In conductive deafness, BC > AC – negative Rinne.
False negative Rinne is seen in severe unilateral sensorineural deafness. This is confirmed by Weber test.
 
Weber Test
Bone conduction test.
In conductive deafness – sound lateralized to the deaf ear.
In sensorineural deafness – sound lateralized to the better ear.
 
Absolute Bone Conduction Test
  • In conductive deafness – ABC is normal.
  • In sensorineural deafness – ABC is shortened (Diagnostic).
 
Gelle's Test
Bone conduction test.
Note:
  • AC signifies conduction through ossicular pathway.
  • BC signifies conduction through sensory neural pathway.
 
AUDIOMETRY
  1. Subjective –
    1. Pure tone audiometry
    2. Speech audiometry
    3. ABLB or Fowler's test
    4. Tests for adaptation – Bekesy audiometry, Tone-Decay test.
      40
  2. Objective –
    1. Tympanometry
    2. Brainstem evoked response audiometry (BERA or ABR).
 
Pure Tone Audiometry
Most common type.
  • Frequencies used from 250-8000 Hz.
  • Response are measured in decibels (a logarithmic unit).
Interpretations:
  1. Conductive deafness – air-bone gap (threshold elevation for BC > AC).
  2. Sensorineural deafness – greater threshold at higher frequencies, except in acoustic trauma (noise-induced deafness) where there is a sudden dip at 4000 Hz.
  3. Otosclerosis – conductive deafness (AB gap) with a dip at 2000 Hz (Carhart's notch).
 
Speech Audiometry
Response is speech discrimination at phonetically balanced words.
  1. Conductive deafness – 95-100 percent speech discrimination.
  2. In cochlear deafness – 50-80 percent speech discrimination.
  3. In retro-cochlear deafness – 0-50 percent speech discrimination.
 
ABLB or Fowler's Test
Test of recruitment.
The graph is called the laddergram.
  • In conductive deafness and in normal ear – negative.
  • In sensorineural deafness (e.g. presbyacusis) – positive.
  • In cochlear lesion (e.g. Ménière's disease) – positive.
 
Tone-Decay Test
A decay > 30 dB is diagnostic of retrocochlear lesion (acoustic neuroma).41
 
Tympanometry
Or impendence audiometry.
Test of impendence of middle ear to sound.
Graph is called the tympanogram.
Interpretations:
Type A – normal.
Type B (flat or dome shaped curve) – secretory otitis media.
Type C – Eustachian tube blockade.
Type D – ossicular disruption.
 
Stapedial Reflex
This is due to contraction of middle ear muscles (tensor tympani and stapedius).
This is absent in otosclerosis.
This is a protective reflex against loud sound.
 
Brainstem Evoked Response Audiometry (BERA)
Most useful test for localization of lesion in sensorineural deafness.
 
DEAFNESS
 
Definition
Hearing loss more than 90 dB in the better ear or total hearing loss.
 
Etiology
  1. Conductive deafness –
    1. Chronic suppurative otitis media – most common cause.
    2. Secretory otitis media – most common non-suppurative cause in children.
    3. Otosclerosis – most common cause in adults.
  2. Sensorineural deafness –
    1. Childhood deafness –
      1. Hereditary – autosomal recessive, e.g. Pendred syndrome, trisomy 18, familial sensorineural deafness.
      2. Meningitis – most common cause of sensorineural deafness in children.
      3. Congenital infections – TORCH.
        42
      4. Others – unconjugated hyperbilirubinemia, asphyxia.
    2. Presbyacusis or senile deafness – most common cause.
Note: other causes of congenital deafness:
  1. Alport's syndrome
  2. Usher's syndrome
  3. Pendred syndrome
  4. Treacher-Collin syndrome
Tests at a glance
Normal
Cochlear lesion
Retro-cochlear lesion
Pure tone audiometry
Normal
Sensori neural deafness
Sensorineural deafness
Speech discrimination
90-100%
50-80%
0-50%
Recruitment (ABLB)
Absent
Positive
Negative
SISI (short increment sensitivity index)
0-15%
> 70%
0-20%
Tone decay
0-15 dB
< 25 dB
> 25 dB
Stapedial reflex
Normal
Normal
Abnormal
BERA
Normal interval between I and V
Normal
V wave delayed or absent
ORAL CAVITY
 
ORAL MUCOSA
 
Pigmented Lesions
  1. Heavy metal poisoning (lead, mercury) – blue-black line along the gingival margin.
  2. Black hairy tongue – elongation of filiform papillae due to tobacco, chromogenic agents.
  3. Fordyce's spot – ectopic sebaceous gland, situated on the lips.
  4. Forchheimer's spot (palatal petechiae) – rubella, infectious mononucleosis, scarlet fever.
    43
 
White Lesion
Hairy leukoplakia – HIV infection.
 
TONGUE
 
Macroglossia
 
Etiology
  1. Down's syndrome
  2. Pierre-Robin syndrome
  3. Hurler's syndrome
  4. Primary amyloidosis
  5. Acromegaly, cretinism
  6. Actinomycosis, tertiary syphilis.
 
Geographic Tongue
Benign migratory glossitis. Asymptomatic and require no treatment.
 
Strawberry/Raspberry Tongue
Scarlet fever.
 
Bald Tongue
Xerostomia, pernicious anemia, iron deficiency anemia, pellagra, syphilis.
PULMONARY FUNCTION
 
REGULATION OF RESPIRATION
 
Higher Center
Respiratory center is situated in the medulla.
Pre-Bottzinger complex in medulla is the respiratory pacemaker.
Note: Expiration is passive during quiet breathing.
If brainstem is transected at the inferior border of pons, spontaneous respiration continues but becomes irregular and gasping.44
 
CHEMICAL CONTROL OF BREATHING
 
Chemoreceptor
  1. Carotid body – situated near carotid bifurcation on each side.
    Note: blood flow to each carotid body = 2000 ml/100 gm/minute.
  2. Aortic body – near the arch of aorta.
Stimulus:
  1. Increased H+ ion concentration in arterial blood – acidosis.
  2. Decreased PO2 – hypoxia.
Both lead to hyperventilation.
Medullary chemoreceptor: These mediate responses produced by increased arterial PCO2 via CSF and brain interstitial H+ concentration.
Note: CO2 is most permeable to BBB.
Effect of CO2: A rise of arterial PCO2 produces hyperventilation which washes out excess CO2. However, when the CO2 concentration of inspired gas exceeds 7%, there is rise of PCO2 despite hyperventilation. The resultant hypercarbia depresses central nervous system including the respiratory center and produces headache, confusion and coma (CO2 narcosis).
 
NON-CHEMICAL CONTROL OF BREATHING
Airway and lung receptors – mediated by vagus nerve.
Non-chemical control of breathing
Receptors
Location
Stimulus
Response
Slow adapting (myelinated)
Airway smooth muscle
Lung inflation
Hering-Breur reflex - increased duration of expiration
Rapidly adapting (myelinated)
Airway epithelial cells
Lung hyper-inflation exogenous/ endogenous substances (histamine, PG)
Hyperpnoea, cough, bron-choconstriction, mucus secretion
Unmyelinated C fibers J receptors
Alveolar interstitium (juxta- capillary)
Lung hyper-inflation
Apnea followed by rapid breathing, bradycardia and hypotension (pulmonary chemoreflex)
45
 
Effects of Exercise
  1. Increased pulmonary blood flow.
  2. Increased alveolar-capillary PO2 gradient (PO2 of pulmonary blood falls from 40 to 25 mmHg) – more O2 enter the circulation.
  3. Respiration –
Initially abrupt increase due to impulses from propioceptors in muscles, joints, tendons.
Followed after a brief pause by more gradual increase due to humoral responses.
Mechanism – increase in body temperature, increase in plasma K+ induced by exercise.
Note: arterial pH, PCO2 and PO2 remains normal in moderate exercise.
 
CLINICS
 
Types of Breathing
  1. Vesicular breathing:
    Produced by air passage through tracheobronchial tree up to alveoli.
    Variations:
    1. Diminished vesicular – pleural effusion, pneumothorax, empyema.
    2. Prolonged expiration – bronchial asthma, COPD.
    3. Absent – pneumonia, massive effusion, collapse with obstructed bronchus.
  2. Bronchial breathing:
    Air passage through tracheobronchial tree and a patent bronchus (not in alveoli).
    Variations:
    1. Tubular – consolidation.
    2. Cavernous – cavity lung (e.g. TB)
    3. Amphoric – bronchopleural fistula (open pneumothorax).
 
Cheyne-Stokes Breathing
Alternate phases of apnea and hyperapnea, each phase lasting for 30 seconds and whole cycle completed in 2 minutes.46
Seen in:
  1. Cardiac failure
  2. Uremia
  3. Narcotic poisoning
  4. Increased ICT
  5. Normal in infants and adults during sleep.
 
Kussmaul's Breathing
Deep respiration at a rapid rate.
Seen in:
  1. Diabetic ketoacidosis
  2. Uremia
  3. Cerebral tumor
  4. Hepatic coma.
 
PERCUSSION
  • Normal – resonant.
  • Dull – stony dull in pleural effusion and woody dull in consolidation.
  • Tympanic – pneumothorax.
  • Hyperresonant – emphysema.
  • Impaired – thickened pleura.
 
PULMONARY EDEMA
 
Development
Two stages:
  1. Interstitial edema – characterized by tachypnea, decreased gas exchange and Kerley B lines on chest X-ray, is due to increased pulmonary vascular pressure, increased lymphatic flow and a net gain of water in extravascular space.
  2. Alveolar edema – characterized by full blown symptoms with bilateral rales and ronchi and diffuse haziness of lung fields on chest X-ray. This is due to disruption of alveolar capillary membrane.
Clinical feature: Pink (blood-stained) frothy sputum.
 
Etiology
  1. Increased PCWP –
    1. Cardiogenic – mitral stenosis, left heart failure.
    2. Non-cardiogenic – severe liver disease, nephrotic syndrome, protein losing enteropathy.
      47
  2. Normal PCWP –
    1. High altitude
    2. Narcotic overdose – most commonly with heroin.
    3. Pulmonary embolism
    4. Cardiopulmonary bypass.
  3. Others – radiation pneumonitis.
    Unilateral pulmonary edema is seen in:
    1. Lymphoma,
    2. Aspiration
    3. Post-pleural tap aspiration.
Note: ‘Bat wing’ appearance in CXR is seen in cardiogenic pulmonary edema.
 
PULMONARY HYPERTENSION
  • Normal pulmonary arterial pressure is 25/10 mmHg.
  • Pulmonary hypertension means pressure > 35/15 mmHg.
Etiology:
  1. Left heart failure – MS, MR, AS, AR.
  2. Congenital heart diseases – ASD, VSD, PDA.
  3. Pulmonary thromboembolism
  4. SLE, PAN
  5. Sickle cell anemia
  6. Progressive systemic sclerosis
  7. Toxic oil (rape seed) syndrome.
Treatment
General – diuretics, anticoagulant.
Specific – calcium channel blocker, endothelin receptor antagonist (Bostenan), phophodiesterase – 5 inhibitor (sildenafil), prostacyclins (Iloprost).
 
COUGH
  • Staccato paroxysm of cough – whooping cough, chlamydia infection.
  • Barking or brassy cough – laryngotracheobronchitis.
  • Hawking cough – post-nasal drip.
  • Honking cough – psychotic.
  • Bovine cough – laryngeal paralysis.
 
STRIDOR
  • Laryngomalacia – most common cause of stridor (present at birth), intermittent in nature, increased by crying and relieved on lying down.
    48
  • Laryngotracheobronchitis – presents at 1-5 years of age.
  • Acute epiglottitis
  • Subglottic hemangioma – presents at 3-6 months of age, increases on crying, managed by tracheostomy, steroid and CO2 laser.
 
HEMOPTYSIS
  • Source of bleeding – bronchial arteries.
  • Most common site of bleeding – tracheobronchial tree.
Etiology:
i. Bronchitis
ii. Bronchogenic Ca
iii. Bronchiectasis
Produces
iv. Tuberculosis – most common cause.
massive
v. Aspergilloma
hemoptysis.
vi. Foreign body.
 
CYANOSIS
Produced by:
  • Reduced Hb > 5 gm/dl.
  • Sulphemoglobin > 0.5 gm/dl.
  • Methemoglobin > 1.5 gm/dl.
Etiology:
  1. Central cyanosis:
    1. Congenital heart diseases – tetralogy of Fallot (most common), Eisenmenger's complex (ASD, VSD or PDA with reversal of shunt due to pulmonary hypertension).
    2. Acute pulmonary edema (due to LVF) – most common cardiac cause.
  2. Peripheral cyanosis:
    1. Exposure to cold – most common cause.
    2. CCF.
  3. Differential cyanosis:
    1. Hands blue and feet red – coarctation of aorta with transposition of great vessels.
    2. Hands red and feet blue – PDA with reversal of shunt.
 
CLUBBING AND HYPERTROPHIC OSTEOARTHROPATHY
Degrees
  • First degree – increased fluctuation of nail bed (earliest change) with loss of onychodermal angle (normal 120°).
    49
  • Second degree – first degree + increased diameter of nail.
  • Third degree – second degree + increased pulp tissue.
  • Fourth degree – third degree + swelling of wrist and ankle due to HOA.
Etiology:
  1. Cardiac:
    1. Congenital cyanotic heart diseases.
    2. Infective endocarditis.
    3. Aortic aneurysm.
    4. Atrial myxoma.
  2. Lung:
    1. Neoplasms – bronchogenic Ca (most common cause), mesothelioma.
    2. Infections – empyema, lung abscess, bronchiectasis.
    3. Pulmonary fibrosis – interstitial lung disease.
    4. Cystic fibrosis.
  3. Ulcerative colitis and Crohn's disease.
  4. Biliary cirrhosis
  5. Idiopathic
  6. Neoplasms
  7. Genetic – autosomal dominant.
  8. Hyperthyroidism.
 
Hypertrophic Osteoarthropathy (HOA)
It is subperiosteal new bone formation in the proximal and distal diaphyses of tibia, fibula, radius and ulna. Bone involvement is bilateral and symmetrical.
Diagnosis: Bone X-ray.
Note: HOA is most commonly seen in bronchogenic Ca.
EDEMA
 
Total Body Water
  • Water constitutes 60 percent of body weight.
  • 2/3rd of TBW is intracellular and remaining 1/3rd is extracellular.
  • ECF is distributed in interstitial fluid (75%) and plasma (25%).
    50
  • TBW is measured by D2O method.
  • Edema is an increase in fluid volume in the interstitial space.
 
Pathogenesis
Two primary forces acting in vascular system regulates fluid movement are:
  1. Hydrostatic pressure – which tries to drive out water and
  2. Oncotic pressure (primarily contributed by plasma proteins, mainly albumin) –which tries to retain water.
 
Etiology
  1. Increased hydrostatic pressure – CCF – most common cause.
  2. Decreased oncotic pressure (fall in plasma protein > 85%) –
    1. Nephrotic syndrome
    2. Cirrhosis
    3. Protein losing enteropathy.
  3. Lymphatic obstruction –
    1. Inflammatory edema, e.g. filariasis.
    2. Neoplastic, e.g. breast Ca.
Note: In acute heart failure, there is a fall in hydrostatic pressure in systemic capillaries due to peripheral vasodilatation – edema does not develop.
 
Clinical Types
  • Pitting edema, e.g. in CCF.
  • Non-pitting edema, e.g. in myxedema, filariasis and angioneuritic edema.
 
Differential Diagnosis
  • CCF – starts with edema in the dependant parts (legs).
  • Nephrotic syndrome – starts with facial edema.
  • Cirrhosis – starts with ascites.
  • Hypoproteinemia – periorbital edema.
Facial edema:
Seen in – nephrotic syndrome (hypoproteinemia), trichinosis, allergic reactions, myxedema.51
Idiopathic edema:
Periodic episodes of edema seen in women which is unrelated to the menstrual cycle.
Cause: Orthostatic retention of Na+ and water (not estrogen mediated).
Differential diagnosis: Cyclical or premenstrual edema in which Na+ and water retention occurs secondary to high estrogen.
Treatment: ACE inhibitors may be helpful.
SHOCK
 
Types
  1. Hypovolemic shock – most common clinical type.
    Stages of hypovolemia:
    1. Covert compensated – most common type.
    2. Overt compensated
    3. Decompensated
  2. Cardiogenic shock –
    Most common cause is myocardial infarction (> 40% of LV).
    Features:
    • SBP < 80 mmHg.
    • Cardiac index < 1.8 L/min/mt2.
    • LV filling pressure > 18 mmHg.
    • Pulmonary edema.
  3. Distribution shock due to peripheral vasodilatation, e.g. septic shock, anaphylactic shock.
 
Pathophysiology
Diagnosis
PCWP
Cardiac output
Peripheral vasculature
Hypovolemic shock
Decreased
Decreased
Constriction
Cardiogenic shock
Increased
Decreased
Constriction
Septic shock
Decrease/normal
Increase/normal
Dilatation
52
 
Clinical Feature
Hypotension, tachycardia, tachypnea, oliguria, metabolic acidosis, cold and clammy skin (in septic shock, skin may be flushed and hot due to vasodilatation).
Grading of hypovolemia:
  • Mild (< 20%) – cold extremities, anxiety.
  • Moderate (20-40%) – same + tachycardia, tachypnea, decreased urine output.
  • Severe (> 40%) – decreased BP, marked tachycardia.
 
Management
  1. Hypovolemic shock –
    Fluid infusion is the main treatment.
    Initial choice of fluid is crystalloids (according to Harrison) and colloids (according to Bailey and Love).
    In severe hypovolemia ionotropics (dopamine) may be used.
  2. Cardiogenic shock –
    Intra-aortic balloon pump, ionotropic drugs - dopamine, dobutamine (drug of choice in pump failure), amrinone, milrinone.
 
Monitoring
  • Urine output – most useful method. It should be > 0.5 ml/kg/hr.
  • PCWP and CVP are not very helpful in determining left ventricular function (tissue perfusion) in shock.
 
CARDIAC ARREST AND SUDDEN CARDIAC DEATH
Cardiac arrest is the most common cause of sudden death.
 
Etiology
  1. Electrical disturbance – ventricular fibrillation is the most common cause of cardiac arrest. Others are ventricular tachycardia and asystole.
  2. Decreased cardiac output – acute pulmonary emboli, ruptured aortic aneurysm, cardiac rupture after myocardial infarction.
    53
 
Structural Defect
  • Atherosclerotic heart disease – most common cause.
  • Cardiomyopathy.
  • Conducting system disease.
 
Predisposing Factors
  1. Hypoxia – most common cause.
  2. Electrolyte disturbance – Hypokalemia, hypocalcemia (heart stops at diastole).
 
Management
  • Heimlich maneuver – for dislodging an aspirated foreign body.
  • Cardiopulmonary resuscitation – has two components –
  1. Chest compression (cardiac massage) – over the lower sternum, at the rate of 80-100/minute, force to depress sternum 3-5 cm (1.5-2 inches).
  2. Ventilation – 10-12 times/minute, i.e. compression: Ventilation ratio = 5:1 (2 in succession every 15 compression when one person is performing).
Note: Maximum cardiac index attained by external compression is 40 percent (normal is 2.6-4.2 L/min/mt2).
Advanced life support:
  1. Endotracheal intubation
  2. Defibrillation/cardioversion and/pacing – adrenaline is given if defibrillation fails. If not controlled completely, lignocaine/procainamide/bretylium is given.
  3. IV fluid.
  4. IV NaHCO3 – in acidotic patients.
  5. IV calcium gluconate – in hyperkalemia, hypocalcemia, CCB therapy.
 
Prognosis
  • Those with VT carry best prognosis.
  • Asystole carries the worst prognosis.
    54
GI FUNCTIONS
 
Dysphagia
  1. Type of food:
    To solids – mechanical obstruction, e.g. malignancy.
    To both solids and liquid – achalasia, diffuse esophageal spasm.
    Scleroderma – Dysphagia to solid unrelated to posture and dysphagia to liquid in recumbent but not in upright posture.
  2. Duration:
    Progressive dysphagia – malignancy.
    Episodic dysphagia – lower esophageal ring.
  3. Odynophagia (painful swallowing: fungal or herpetic esophagitis or pill-induced esophagitis.
 
Vomiting
Mechanism:
  1. Vomiting center – in dorsal portion of lateral reticular formation in medulla.
  2. CTZ – in area prostema of the floor of fourth ventricle.
Peripheral muscles:
  1. Abdominal musculature – provides the main ejection force.
  2. Diaphragm.
  3. Intercostal muscles.
Clinical feature:
  1. Type: Projectile vomiting in increased ICT.
  2. Time: Early morning nausea – early pregnancy, uremia, alcoholic gastritis.
    Shortly after taking food – peptic ulcer.
    4-6 hours after taking food – gastric retention.
  3. Character: Increased acid content – gastric outlet obstruction duet to Z-E syndrome.
    Absent free HCl – gastric carcinoma.
    Bile – obstruction below ampulla of Vater.
Complications:
  1. Metabolic – hypochloremic, hypokalemic, metabolic alkalosis.
  2. Rupture of esophagus – Boerhauve's syndrome.
    55
  3. Hematemesis – Mallory-Weiss tear.
  4. Aspiration pneumonia in comatose patients.
Differential diagnosis:
  1. Hiccups – seen in uremia, acidosis, anoxia, systemic infections. Cause is gastric distension.
  2. Rumination – seen in bulimia nervosa.
 
DIARRHEA
 
Acute
  1. Watery diarrhea – enteric viruses (rotavirus – most common), EPEC, cholera, protozoa, helminths.
  2. Watery then bloody diarrhea – campylobactor, shigella, V. parahemolyticus.
  3. Bloody diarrhea – salmonella, shigella, EIEC, yersinia, entamoeba.
Note:
  • Most common cause of diarrhea in neonates – E.coli.
  • Most common cause of diarrhea in infants/children – rotavirus.
  • Most common cause of diarrhea in AIDS patients – Cryptosporidium.
  • Preformed toxins are produced by –
Bacillus cereus, Staphylococcus aureus and Clostridium perfringens (mnemonic – BSC).
 
Chronic
  1. Inflammatory – ulcerative colitis, Crohn's disease, radiation, eosinophilic gastroenteritis.
  2. Osmotic – lactose intolerance (milk allergy), pancreatic cholera, tropical sprue, Whipple's disease, celiac sprue, short bowel syndrome, abetalipoproteinemia.
  3. Secretory (watery) – Z-E syndrome, villous adenoma, carcinoid syndrome, medullary Ca of thyroid, cholerrheic diarrhea, and diabetes mellitus type I due to altered motility.
Note:
Intestinal lymphangiectasia – causes selective protein loss with steatorrhea with preserved carbohydrate absorption.56
 
Diagnosis
  1. Inflammatory diarrhea – hallmark is the presence of blood and leukocytes in stool.
    Blood is detected by – Benedict's reaction.
    Leukocytes are detected by – Wright's or methylene blue stain.
  2. Malabsorption –
    1. Stool fat – increased in pancreatic insufficiency.
    2. Carbohydrate – d-xylose absorption test in celiac/tropical sprue.
    3. Intestinal biopsy – definitive test for malabsorption. Diagnostic in Whipple's disease, abetalipoproteinemia, agammaglobulinemia.
    4. α1-antitrypsin assay – best test for protein-losing enteropathy.
    5. Schilling's test – for vitamin B12 assay, done in pernicious anemia, pancreatic insufficiency.
    6. Bacterial growth – 14C-xylose breath test.
    7. Fecal osmolality – to differentiate osmotic from secretory diarrhea. Fecal osmotic gap > 50 mosmol/kg H2O suggests osmotic diarrhea.
 
Treatment
  1. Traveler's diarrhea (ETEC) – bismuth subsalicylate, diphenoxylate + atropine, loperamide.
  2. Oral rehydration – for mild (5-7% of body weight) or moderate (7.5-10% body weight) dehydration.
    WHO ORS:
    Principle: Glucose promotes absorption of Na+.
    Composition:
    Ingredient
    Quantity
    (in gram)
    (in mmol/L)
    NaCl
    3.5
    Na+
    90
    NaHCO3
    2.5
    K+
    20
    KCl
    1.5
    Cl−
    80
    Glucose
    20
    Citrate
    10
    Potable water
    1 lit.
    Glucose
    110
    Or Trisodium citrate dehydrate in place of NaHCO3
    2.9
    Total
    310
    Dose – 75 ml/kg in the first 4 hours then 10-20 ml/kg for each liquid stool.57
    Drawback – when used in non-choleric diarrhea, it produces periorbital edema due to excess Na+ absorption (hypernatremic dehydration – causes irritability).
    New formula ORS: For cholera and non-cholera diarrhea.
    It has low Na+ (NaCl – 2.6 gm, Na+ 75 mmol/lit) and low glucose (glucose – 13.5 gm, 75 mmol/lit).
    Super ORS: ORS that in addition to rehydration increases intestinal absorption and decreases stool formation.
    For example, alanine, glycine added ORS, boiled rice – best for developing countries.
  3. IV rehydration – for severe dehydration.
    Indication: Fluid loss > 10 percent of body weight.
    1. Dhaka fluid – contains 5 gm of NaCl, 1 gm of KCl and 4 gm of NaHCO3 dissolved in 1 liter of water or 5 percent dextrose.
    2. Ringer's lactate – recommended by WHO. It provides
      Na+ - 130 mmol/l
      K+ - 4 mmol/l
      Cl− - 109 mmol/l
      Lactate – 28 mmol/l
      Total – 271 mmol/l.
    Dose: 30 ml/kg in the first hour and 70 ml/kg in the next 5 hours for infants < 1 year.
    In older children – same dose should be given in ½ hour and 2½ hours, respectively.
  4. Other drugs –
    Sulfasalazine – in IBD.
    Octreotide – in carcinoid syndrome.
    Clonidine – in opiate withdrawal and diabetic diarrhea.
    Indomethacin - in medullary Ca of thyroid and villous adenoma.
    Cholestyramine – drug of choice in bile salt malabsorption.
    Metronidazole/vancomycin – in pseudomembranous colitis.
 
WEIGHT
Weight gain
Weight loss
Hypothyroidism – Myxedema
Hyperthyroidism
Cushing's syndrome
Pheochromocytoma
Craniopharyngioma
Diabetes mellitus
Insulinoma
58
 
GI BLEEDING
Hematemesis is vomiting of blood produced by pathology proximal to the ligament of Treitz.
At least 60 ml of blood is required to produce a single black stool and blood should remain for at least 8 hours in the gut.
 
Etiology
Upper GI bleeding:
  1. Erosive hemorrhagic gastropathy (NSAID induced)
  2. Duodenal ulcer – most common cause.
  3. Gastric ulcer.
  4. Mallory-Weiss tear.
  5. Esophageal varices.
  6. AV malformation.
  7. Gastric tumors – least common cause. Most common gastric tumor to bleed is leiomyoma.
All the above conditions can produce both hematemesis and melena.
Note: Most common cause of upper GI bleeding in children is from esophageal varices due to portal hypertension.
Lower GI bleeding:
Age < 55 years
Age > 55 years
Hemorrhoids – most common cause
Hemorrhoids, fissure – scant bleeding.
Colitis (IBD, infections)
Diverticulosis – most common cause of massive bleeding.
Diverticulosis
Angiodysplasia.
They usually produce hematochezia.
Note: Most common cause of bleeding per rectum in children is rectal polyp.
 
Investigation
Occult blood – by card test for Hb peroxidase. False negative test may be due to chronic ingestion of vitamin C.59
Most sensitive method to detect GI bleeding is radiolabelled erythrocyte screening which can detect blood as small as 0.01-0.05 ml/min.
Angiography – may detect bleeding as small as 0.5 ml/min.
JAUNDICE
 
BILIRUBIN METABOLISM
Bilirubin is produced by catabolism of heme (the iron porphyrin in Hb).
 
Heme
 
Synthesis
It is essentially the incorporation of ferrous ion into protoporphyrin III – the parent porphyrin in heme.
Heme synthesis occurs in mitochondria in most mammalian cells except the RBC which does not contain mitochondria.
The rate limiting enzyme is ALA synthetase in liver (dependant on pyridoxal phosphate).
Note: Lead poisoning causes increased protoporphyrin in RBC and increased ALA and coproporphyrin in urine.
 
Bilirubin
Heme is catabolized to bilirubin in the RE cells of peripheral tissues through the following steps:
Hb (red) → hemin (blue-purple) → biliverdin (green) → bilirubin (yellow).
Note: The color change in a bruise or hematoma is due to the above reason.
  • 1 gm Hb yields 35 mg of bilirubin.
  • Daily production in human = 250-350 mg.
    60
 
Types
Bilirubin
Unconjugated
Conjugated
Water solubility
No
Yes
Renal excretion
No
Yes
Albumin binding
+++
+
Van den Bergh reaction
Indirect
Direct
Note: Unconjugated bilirubin = total bilirubin – conjugated bilirubin (in VDB test).
 
Metabolism
It consists of the following steps:
  1. Uptake – of unconjugated bilirubin bound to albumin by liver.
  2. Conjugation – with glucoronide by UDP-glucuronyl transferase. Conjugation makes it water soluble.
  3. Secretion into bile and into GI tract.
  4. Intestinal circulation – conjugated bilirubin is not absorbed by intestine. In terminal ileum and colon, it is converted to urobilinogen which is excreted in the feces. Some urobilinogen is absorbed, taken up by the portal vein and re-excreted by the liver (enterohepatic circulation).
In unconjugated hyperbilirubinemia, some urobilinogen is also excreted in urine (as in hemolysis) due to excess production of bile pigments (acholuric jaundice).
In obstructive jaundice, conjugated bilirubin may be present in urine without urobilinogen (choleric jaundice). (See below)
 
JAUNDICE
Normal serum bilirubin level –
  • Total = 0.3 to 1.0 mg/dl
  • Conjugated (direct) = 0.1 to 0.3 mg/dl.
  • Unconjugated (indirect) = 0.2 to 0.7 mg/dl.
  • Hyperbilirubinemia is bilirubin > 1.0 mg/dl.
  • Latent jaundice is bilirubin 1.0 – 2.5 mg/dl.
  • Clinical jaundice is bilirubin > 2.5 mg/dl.
  • Most common site for detecting jaundice is – upper bulbar conjunctiva.
  • Scleral tissue has high level of elastin which has high affinity for bilirubin.
    61
 
Classification
  1. Unconjugated hyperbilirubinemia (indirect):
    1. Overproduction – hemolysis.
      1. Rh incompatibility – most common cause in newborn.
      2. ABO incompatibility.
      3. Thalassemia.
      4. Vitamin K.
    2. Decreased bilirubin conjugation (decreased hepatic glucuronyl transferase activity).
      1. Gilbert syndrome (mild deficiency).
      2. Crigler -Najjar type II (moderate deficiency) – AD.
      3. Crigler-Najjar type I (absent enzyme) –AR.
      4. Physiological jaundice of neonates.
      5. Breast milk jaundice.
      6. Septicemia.
  2. Conjugated (Direct) hyperbilirubinemia:
    Direct bilirubin > 15 percent of total bilirubin.
    1. Impaired hepatic excretion (intrahepatic defect)
      1. Dubin-Johnson syndrome.
      2. Rotor syndrome.
      3. Hepatocellular disease – hepatitis, cirrhosis.
      4. Alcoholic liver disease.
    2. Extrahepatic biliary obstruction –
      1. CBD stones – Most common cause of benign surgical jaundice.
      2. Biliary atresia – Most common cause in newborn.
      3. Others – choledochal cyst, Pancreatic Ca.
 
Evaluation of Jaundice
Condition
Serum bilirubin
Urine
Fecal urobilinogen
Urobilinogen
Bilirubin
Normal
D + I
Mild +
Absent
Present
Hemolysis
Increased I (indirect)
Increased
Absent (acholuric)
Increased
Hepatitis
Increased D + I
Decreased (in micro-obstruction)
+ (in micro- obstruction)
Decreased
Obstruction
Increased D (direct)
Absent
Present (choleric)
—
Note: Bilirubin in urine is detected by Ehrlich's test.62
LFT:
  1. Unconjugated – no enzymatic disturbance (e.g. hemolysis)
  2. Conjugated -
    1. Hepatitis – increased ALT and AST.
    2. Obstruction – increased alkaline phosphatase, 5'–nucleotidase and/or GGT.
 
NEONATAL JAUNDICE
 
Classification
  1. Early jaundice (<10 days) – unconjugated.
    1. First 24 hours – Rh incompatibility (Most common cause), ABO incompatibility, others – G-6PD deficiency, Vitamin K.
    2. After 24 hours - Physiological jaundice, Cephalhematoma, Congenital hemolytic anemia – Gilbert syndrome and Crigler-Najjar syndrome, Galactosemia.
  2. Prolonged jaundice (> 10 days):
    1. Unconjugated – Breast milk jaundice, Septicemia.
    2. Conjugated – Congenital infections (TORCH, etc),
      Dubin-Johnson, Rotor syndrome,
      Hypothyroidism,
      Extrahepatic biliary atresia,
      Intrahepatic dilatation of bile duct – Caroli's disease.
      Choledochal cyst.
      Idiopathic infantile hepatitis – most common cause.
 
EARLY JAUNDICE
 
Hemolytic Disease of Newborn
Due to isoimmunization (Erythroblastosis fetalis) –
Rh incompatibility: Most common cause.
Mechanism: Anti–D antibody (IgG) in a sensitized mother (Rh –ve) may cross the placenta and produce hemolysis in Rh +ve fetus (not in first pregnancy).
Mechanism of sensitization – APH, PPH, PIH, CS, post-dated pregnancy.
Note: Immunization occurs when > 0.1 ml of fetal blood enters maternal circulation.63
Associated ABO incompatibility reduces the chance of Rh–immunization.
Manifestations:
  1. Hydrops fetalis – Most serious form.
    Diagnosis:
    USG – Edema of scalp, skin and pleural / pericardial effusion, ascites (large abdomen).
    X-ray – ‘Buddha’ position of head.
    Placenta – large due to hyperplasia.
  2. Neonatal jaundice – develops within 24 hours after birth.
  3. Congenital anemia of newborn – red cell destruction continues for up to 6 weeks.
Diagnosis:
  1. Mother -
    Quantitative assay –
    Maternal serum anti-D antibody level –
    < 4 IU/ml – low risk
    4-10 IU/ml – moderate risk.
    > 10 IU/ml – severe risk.
    zoom view
  2. Amniocentesis: To assess disease progression.
    Time:
    1. No previous history – at 30-32 weeks.
    2. Positive previous history – at least 10 weeks prior to previous stillbirth (usually before 20 weeks).
    Inference: Spectophotometric analysis of amniotic fluid shows optical density difference at 450 nm with ‘deviation bulge’ in Rh hemolytic disease.
    The ‘deviation bulge’ is plotted in Liley's chart. If it falls in the –
    1. Low zone (zone I) – continue pregnancy.
    2. Mid zone (zone II) – may require termination after 34 weeks.
      64
    3. High zone (zone III) – severely affected child, if > 34 weeks – termination, if < 34 weeks – intrauterine fetal transfusion.
  3. Baby: Sensitized baby show positive direct Coomb's test.
Prevention: Administration of Rh anti-D immunoglobulin to unsensitized (Coomb's negative) mother within 72 hours following childbirth (300 µg), abortion (100 µg) and ectopic pregnancy (50 µg), amniocentesis, external cephalic version.
Management: See below.
ABO incompatibility: Occurs when the mother is group O and the baby is either group A or B.
First baby may be affected (c.f. Rh incompatibility).
Non-immune hemolysis: G6PD deficiency, vitamin K.
Note: Causes of non-immune hydrops (fetal edema) –
  1. Down's syndrome
  2. Congenital cardiac anomaly
  3. Beta thalassemia, G6PD deficiency
  4. Infection – parvovirus, toxoplasma, rubella, syphilis.
 
Physiological Jaundice of Newborn
Incidence: 65 percent
Features: Appears after 30 hours (on third day). Peak level of bilirubin maximum 12 mg/dl on day 4 or 5. Rate of increase in bilirubin concentration < 5 mg/day. Disappears by 7 – 14 days.
Aggravating factors: Prematurity, hypoglycemia, hypoxia, dehydration, intestinal stasis.
 
Kernicterus
Cause: Unconjugated hyperbilirubinemia > 20 mg/dl or serum bilirubin:protein ratio > 3:5.
Pathology: Damage to basal ganglia (most common), hippocampus and subthalamic nuclei.
Note: Cerebral cortex is spared.
Risk factors: Prematurity, hypoglycemia, hypoxia, hypothermia, ketoacidosis. Drugs – Sulfamethoxazole, Gentamicin, Novobiocin.65
 
Management of Early Jaundice
  1. Phototherapy:
    Indications – Serum bilirubin > 18 mg/dl at term.
    1. Hemolytic (ABO) – bilirubin level –
      ≥ 10 at < 12 hours.
      12 – 14 at < 18 hours.
      ≥ 15 at > 24 hours.
    2. Non-hemolytic – bilirubin level –
      ≥ 15 at < 2 days.
      ≥ 18 at 2-3 days.
      ≥ 20 at 3-4 days.
    Mechanism: Photoisomerization of bilirubin (E isomerism), toxic 4Z-15Z bilirubin is converted to 4Z-15E bilirubin.
    • Blue light is most sensitive.
    Complication:
    1. Dehydration due to insensible water loss – most common.
    2. Diarrhea – most common cause in newborn.
    3. Bronzing of skin.
    4. Retinal damage.
  2. Exchange transfusion:
    Indication:
    1. Term baby –
      1. Unconjugated bilirubin > 25-28 mg/dl in non-hemolytic cases and > 18-20 mg/dl in hemolytic cases.
      2. Serum bilirubin: Protein ratio > 3.5.
    2. Erythroblastosis -
      1. Maternal antibody titer > 1:64
      2. Baby direct Coomb's positive with body weight < 2.5 kg.
      3. Cord Hb < 10 gm/dl and cord bilirubin > 5 mg/dl.
      4. Previous history of affected child.
Method: Rh-negative whole blood from unsensitized donors with same ABO blood group.
Complication:
  1. Hypovolemia – shock (usually hypervolemia occurs).
  2. Citrate tetany.
  3. Cardiac arrest.
  4. Hypercalcemia.
    66
 
PROLONGED JAUNDICE
 
Breast Milk Jaundice
  • Gradual onset (after 10 days).
  • Peak bilirubin level 25 mg/dl on 2nd or 3rd week.
  • Settles in 6 hours, may continue up to 4 months.
  • Cause – pregnanediol interferes with bilirubin conjugation.
 
Neonatal Cholestatic Jaundice
Etiology:
  1. Idiopathic neonatal hepatitis – most common cause (50-60%).
  2. Extrahepatic biliary atresia – 20 percent.
  3. α1-antitrypsin deficiency – 15 percent.
Investigation:
  • Hepatobiliary imaging – to differentiate between intrahepatic and extrahepatic obstruction.
  • Liver biopsy – giant hepatocytes with many nuclei.
  • Most specific investigation – peroperative cholangiography.
  • Blood – increased alkaline phosphatase, increased 5' nucleosidase, increased GGT (normal 5-40 IU/lit). GGT is increased > 10 times in atresia and > 3 times in neonatal hepatitis.
ASCITES
 
Ascitic Fluid
Differential diagnosis
Exudate
Transudate
Protein
> 2.5 gm/dl
< 2.5 gm/dl
Serum-ascites albumin gradient (SAG)
< 1.1 gm/dl
> 1.1 gm/dl
Specific gravity
> 1.016
< 1.016
67
 
Etiology
  1. Exudate –
    1. Pyogenic peritonitis
    2. Tubercular peritonitis
    3. Pancreatic ascites
    4. Malignancy.
  2. Transudate –
    1. Cirrhosis of liver
    2. CCF
    3. Nephrotic syndrome
    4. Protein-losing enteropathy.
 
Diagnosis
Signs
  • Fluid thrill – at least 2 liter of fluid should be accumulated.
  • Shifting dullness – ½-1 liter of fluid should be accumulated.
  • Puddle sign – can detect fluid as little as 120 ml.
  • USG – best to detect minimal fluid.
  • Diagnostic paracentesis – 50-100 ml of fluid is aspirated.
 
Differential Diagnosis
  1. Tuberculosis: Straw colored or hemorrhagic fluid, exudative in nature, contains cells > 1000/mm3 (70% of them are lymphocytes), confirmation of diagnosis is by peritoneal biopsy.
  2. Chylous ascites: Turbid, milky fluid with TG > 1000 mg/dl.
    Cause: Lymphatic obstruction from trauma, tumor, TB, filariasis, lymphoma, nephrotic syndrome.
  3. Pancreatic ascites:
    Cause: A leaking pseudocyst.
    Exudate with increased amylase level in ascitic fluid.
  4. Mucinous ascites: Pseudomyxoma peritonii – due to mucinous cystic tumors of ovary and appendix.
    Colloid Ca of stomach or colon with peritoneal implant.
  5. Meig's syndrome – Ascites (Transudate) + hydrothorax in a case of fibroma of ovary.
    PseudoMeig's syndrome – Brenner's tumor of ovary.
    68
RENAL FUNCTIONS
 
HEMATURIA
It means presence of intact RBC in urine.
 
Etiology
  1. Surgical – usually painless.
    1. TB of kidney – most common cause of hematuria.
    2. Renal cell carcinoma.
    3. Bladder stone – terminal hematuria.
    4. Bladder Ca – painless hematuria is the earliest and most common symptom.
    5. Renal trauma – hematuria is the cardinal feature.
    6. Urethral rupture – initial hematuria.
  2. Medical causes –
    1. Acute glomerulonephritis – most common medical cause.
    2. Isolated hematuria – IgA nephropathy, H-S purpura.
    3. HUS.
 
Diagnosis
Benzidine test.
 
Investigation
All cases of hematuria should be investigated.
 
Differential Diagnosis of Red Urine
  • Hemoglobinuria, myoglobinuria,
  • Ingestion of beet root, phenolphthalein,
  • Acute intermittent porphyria,
  • Drugs – phenindione, clofazimine, rifampicin.
 
PROTEINURIA
Normal adults excrete 30-150 mg of protein per day of which only 30 mg is albumin and remainder secreted proteins by renal tubules (e.g. Tamm-Horsfall protein).
Proteinuria is – mild (200-500 mg/day), moderate (500 mg/day to 2 gm/day) or massive (> 2 gm/day).
When it exceeds 3.5 gm/day, it is called nephrotic range.69
Nephrotic range proteinuria is seen in – nephrotic syndrome (with edema) or multiple myeloma (without edema).
Diagnosis: Albumin is detected by dipstick method.
 
URINARY CAST
  1. RBC cast – (with hematuria, subnephrotic proteinuria and dysmorphic RBC) – acute glomerulonephritis.
    They are produced as RBC enters the tubules and become trapped in cylindrical mold of Tamm-Horsfall protein.
  2. Hyaline cast – usually normal, but also seen in pre-renal azotemia.
    They are formed in concentrated urine from the normal constituents principally Tamm-Horsfall proteins.
  3. Granular or tubular cast – seen in acute renal failure.
    They are pathognomonic of renal disease.
  4. Waxy cast (degenerated cellular cast) – seen in chronic glomerulonephritis.
  5. Broad cast – seen in chronic renal failure.
  6. White cell cast (with bacteruria) – seen in pyelonephritis.
Note: Tamm-Horsfall protein is a normal protein secreted by the epithelial cells of the loop of Henle.
 
URINE OUTPUT
  • Oliguria – urine output < 400 ml in 24 hours.
  • Polyuria – urine output > 3 liters in 24 hours.
MEDICAL DISORDERS DURING PREGNANCY
 
PHYSIOLOGY
 
Weight Gain
Total weight gain during pregnancy = 11 kg.
In this, 50 percent (∼ 6 kg) is reproductive weight gain and 50 percent (∼ 6 kg) is net maternal weight gain.70
 
Hematological Changes
  1. Blood volume: Increased to maximum 40 percent at 30–32 wks.
    Plasma volume: Increased to maximum 50 percent (Net 1.25 liters).
    RBC volume: Increased to 20 – 30 percent - increased O2 carrying capacity).
    Due to disproportionate increase in plasma and RBC volume, there is a state of hemodilution during pregnancy. (Apparent in Hb concentration by 2% and blood viscosity).
  2. Protein: Total protein increased. But due to hemodilution, plasma protein concentration falls from 7 to 6 percent.
    Albumin decreased and Globulin increased.
    Normal A: G ration of 1.7: 1 is decreased to 1:1.
  3. Coagulation factors: Fibrinogen level increased by 50 percent.
    ESR increased (4 fold increase).
    All procoagulants are increased. Decreased antithrombin III.
    Increased activity of factors 2, 7, 8, 9 and 10.
    Note: For above reasons, there is increased risk of thromboembolism in pregnancy.
    Decreased XI and XIII, increased plasminogen activity.
 
CVS
  1. Cardiac output: Increased to maximum 40 percent at 24–30 wks.
    Clinical Feature:
    Murmurs in pregnancy –
    1. Systolic murmur over apical/pulmonary area.
    2. Continuous hissing murmur over tricuspid area – “mammary murmur”.
      3rd heart sound.
  2. Blood pressure: Mid pregnancy drop to 100/70 mmHg due to decreased peripheral resistance in pregnancy.
  3. Regional circulation: To uterus is increased from 50 ml (non-pregnant) to 750 ml near term.
    Supine hypotension syndrome – postural hypotension during late pregnancy.
    71
 
Metabolism
  1. Protein: Positive nitrogen balance.
  2. Carbohydrate: Maternal fasting hypoglycemia and post-prandial hyperglycemia and hyperinsulinemia.
    Glycosuria is normal in pregnancy.
  3. Fat: increased FFA, triglycerides and ketone bodies.
    Increased cholesterol and phospholipids.
  4. Iron: Total iron requirement in pregnancy = 1000 mg.
    Maximum: Requirement in 2nd half (6–7 mg/day).
  5. Calcium: Daily requirement in pregnancy = 1 to 1.5 gm.
  6. Kilocalories: Daily requirement 2500 (+300 from non-pregnant state).
 
Renal
GFR is increased by 50 percent due to increased renal plasma flow.
 
Respiratory System
  • VC – unaltered, TV increased (+40%), RV decreased (-20%)
  • Respiratory alkalosis compensated by mild acidosis.
Remember:
All are increased in pregnancy except – Hb and plasma protein (apparent fall), albumin and A:G ratio and BP, antithrombin III.
 
HYPERTENSION IN PREGNANCY
 
Pregnancy Induced Hypertension
 
Pre-eclampsia
Definition:
  • BP > 140/90 mmHg
  • Edema and/or proteinuria
  • Pregnancy beyond 20 weeks.
Pathology: Characterized by widespread fibrin deposit due to abnormality in endothelial integrity.
There is decreased synthesis of PGI2 (antiaggregatory and vasodilator) from endothelium and increased sensitivity 72to angiotensin II – vasoconstriction, increased BP and platelet aggregation.
Kidney: Fibrin deposit in basement membrane of glomeruli.
Liver: Periportal hemorrhagic necrosis.
Blood: Hemolytic anemia, elevated LDH and low platelets (HELLP syndrome).
Note: Physiological edema in pregnancy: Due to increased venous pressure of the legs by gravid uterus pressing on common iliac vein. Usually unilateral (more on night leg) and disappears on rest.
Risk factors:
  1. Primigravidae
  2. Family history
  3. Other medical disorders – hypertension, hepatitis.
  4. Pregnancy complication like H. mole, multiple pregnancy, hydramnios, Rh-incompatibility.
Clinical feature: Swelling over ankles in the morning.
Earliest sign: Rapid weight gain > 5 lb a month or 1 lb a week.
Alarming symptoms – Headache, epigastric pain, blurring of vision due to retinal detachment.
Diagnosis:
  • Urine – Proteinuria > 0.3 gm/lit in 24 hours.
  • Blood – increased uric acid> 4.5 mg/dl (marker of pre-eclampsia), increased BUN and increased creatinine.
  • Increased serum LDH.
  • BP – SBP > 30 mmHg or increased DBP > 15 mm Hg.
  • Mean arterial pressure (DBP + 1/3 PP) > 90 mmHg.
  • If DBP>110, it is called severe PIH.
Prevention:
  • Low dose aspirin throughout pregnancy in high-risk patients.
  • Screening test: Roll over test (at 28-32 wks).
Management:
  • Antihypertensive
  • Drugs used in pregnancy73
    • β- blockers.
    • α- methyl dopa - drug of choice.
    • Hydralazine
    • Labetolol
  • Drug contraindicated – ACE inhibitors.
  • Termination –
    • Beyond 37 weeks.
    • Induction of labor by ARM - preferred method.
  • During labor – IV ergotamine following delivering of anterior shoulder is withheld.
 
Eclampsia
 
Definition
  • Pre-eclampsia complicated with convulsion and/or coma.
  • Convulsion is generalized tonic-clonic in nature.
Cause: Cerebral anoxia.
Complication: Pulmonary edema (most common).
Types: Antepartum (most common), intrapartum, postpartum – within 48 hours of delivery.
Prognosis: Bad prognostic features are:
  • SBP > 200 mm Hg.
  • Oliguria and proteinuria > 5 mg/day.
  • Antepartum eclampsia.
Management:
  1. Anticonvulsants –
    1. Lytic cocktail regime (of Menon) - modern regime.
      Contains – Chlorpromazine, Promethazine and Pethidine.
    2. Magnesium sulphate regime (of Pritchard) –
      Therapeutic Mg level – 4-7 mEq/l.
      Monitoring is done by – knee jerks, urine output and respiratory rate.
      Advantage: Least effect on neonates.
      Single most effective drug.
    3. Diazepam (Lean)
    4. Phenytoin.
      In status epilepticus – Thiopentone sodium.
  2. Obstetric: Termination to be done by ARM.
    74
 
Gestational Hypertension
  • BP> 140/90 mmHg beyond 20 wks.
  • No features of pre-eclampsia.
  • Absence of any underlying cause.
  • BP returns to normal within 10 days following delivery.
 
CARDIAC DISEASE
 
Criteria for Diagnosis of HeartDisease in Pregnancy
  1. Diastolic murmur
  2. Loud systolic murmur with thrill.
 
Types
  • Rheumatic – MS is the most common heart disease in pregnancy.
  • Congenital – ASD is the most common congenital disease in pregnancy.
  • CCF in pregnancy occurs around 30 weeks.
 
Mitral Stenosis
Overall most common.
 
Treatment
Closed mitral valvulotomy (balloon valvuloplasty) may be performed between 14-18 wks (Best time of surgery).
Open heart surgery is contraindicated.
 
Mitral Regurgitation
Well tolerated during pregnancy.
 
Aortic Stenosis
  • Worst heart disease in pregnancy.
  • It is a contraindication to pregnancy.
  • Maternal mortality of 15 percent with critical AS.
 
Pulmonary Hypertension
  • Contraindication to pregnancy.
  • Very high maternal mortality.
    75
 
Eisenmenger Syndrome
  • High maternal and fetal mortality (maximum - 50%).
  • Treatment: S and E (absolute indication of abortion).
 
Pulmonary Stenosis
Well tolerated during pregnancy.
 
Coarctation of Aorta
Treatment: Elective CS.
Note: Contraindications to pregnancy –
  1. Critical AS
  2. Pulmonary hypertension and Eisenmenger syndrome.
  3. Marfan's syndrome.
  4. Chronic dilated cardiomyopathy with heart failure.
 
Management of Labour in Heart Disease
  1. Prophylactic antibiotic.
  2. Second stage: Forceps or ventouse at station O.
    IV ergotamine is withheld.
  3. Third stage: Oxytocin drip, IV frusemide.
Note: There is no indication of CS for heart disease. It is done for obstetric indications, except – Coarctation of aorta.
Note: Contraindications to prophylactic ergotamine:
  1. Severe pre-eclampsia and eclampsia
  2. Organic heart diseases
  3. Suspected pleural pregnancy
  4. Rh-negative mother.
 
DVT AND PULMONARY EMBOLISM
 
Causes of Increased Risk of Thromboembolism in Pregnancy
  1. Increased level of all coagulation factors (except XI and XIII)
  2. Decreased antithrombin III level
  3. Decreased fibrinolytic activity.
 
Time
DVT is more common in postpartum (puerperium) period.76
 
Management
  • During pregnancy – IV Heparin.
    [Note: Heparin does not cross the placenta. Warfarin is contraindicated in pregnancy due to increased fetal abnormalities (skeletal and facial anomalies)]
  • During puerperium –
    IV heparin for 7 to 10 days followed by warfarin for 3–6 months.
    Note: Patient on oral anticoagulant should switch over to heparin at 36 wks.
Phlegmasia Alba Dolens (Milk leg/White leg): Due to ilio-femoral vein thrombophlebitis in pregnancy.
Anticoagulant in pregnancy:
  • Up to 12 weeks – heparin,
  • 12–36 weeks – warfarin,
  • 36 weeks–7 days postpartum – heparin,
  • Lactation – warfarin.
 
DIABETES MELLITUS
Pregnancy is diabetogenic because of:
  1. Insulin resistance.
  2. Increased absorption of glucose from gut.
  3. Decreased peripheral utilization.
Glycosuria (due to decreased renal threshold) may be normal in pregnancy.
 
Gestational Diabetes
This is pregnancy induced glucose intolerance.
Diagnosis: Screening – Between 24–28 weeks.
Method:
  • Fasting blood sugar levels after 50 gm oral glucose load.
    ↓ if 1 hr glucose level > 140 mg/dl.
    100 gm oral glucose tolerance test is done after overnight fasting.
  • A diagnosis of gestational diabetes is made if plasma glucose level is
    > 190 mg percent at 1 hour.
    > 165 mg percent at 2 hours.77
    > 145 mg percent at 3 hour
    (any 2 of above 3 values).
Potential candidates for screening:
  • Previous birth to a large baby
  • Recurrent fetal loss
  • Tendency to polyhydramnios.
Treatment: Diet and later insulin.
 
Overt Diabetes
This is pregnancy in a diabetic woman.
Complications:
  • Maternal –
    • Polyhydramnios
    • Pre-eclampsia
    • Preterm labour
    • During labour - shoulder dystocia.
  • Fetal –
    1. Macrosomia.
    2. Hairy pinna.
    3. Congenital anomalies –
    1. Neural tube defects (anencephaly- most common and microcephaly).
    2. Cardiac – asymmetric VSD, transposition of great vessels – most common cardiac anomaly.
    3. Caudal regression - sacral agenesis – most characteristic.
  • Neonatal –
    1. Hypoglycemia - Due to hyperplasia and hypertrophy of fetal islet cells – increased fetal insulin.
    2. Hypocalcemia
    3. Polycythemia
    4. Respiratory distress syndrome.
    5. Hyperbilirubinemia
  • Long-term –
    1. Obesity
    2. Diabetes
    3. Mental retardation
    4. Blindness.
Investigation: For early detection of fetal anomalies –
  1. Glycosylated HbA (HBA1C) estimation before 14 weeks of gestation. A value > 9.5 percent suggests increased risk.
    78
  2. Maternal serum α-FP at 16 weeks. To detect neural tube defects. (α-FP level is increased).
  3. USG at 20 weeks to detect cardiac anomalies – investigation of choice.
Treatment:
  • Target – PP blood glucose level < 140 mg/dl.
  • Agent – Soluble insulin is the agent of choice because it does not cross placenta and insulin demand is increased in pregnancy.
    Note: Oral hypoglycemic agents are contraindicated in pregnancy.
  • Termination of pregnancy – after 37 weeks (because chance of IUFD is increased beyond that period) by CS.
  • β - agonists should be avoided as tocolytics in diabetes.
Contraception:
  • Barrier method is ideal.
  • Progesterone only pill.
 
Glycosuria in Pregnancy
Diagnosis: Second fasting morning specimen of urine is tested for glucose.
Glycosuria on 1 occasion before 20th week and on 2 or more occasions thereafter is an indication for oral GTT.
 
Diabetes Insipidus in Pregnancy
Associated with:
  1. Pre-eclampsia
  2. Oligohydramnios
  3. Hepatic dysfunction.
 
ANEMIA IN PREGNANCY
Definition
  • (WHO) – Hb ≤ 11 gm percent,
  • In India, the value is ≤ 10 gm percent.
Type: Most common type of anemia in India is Dimorphic type due to combined deficiencies of iron, folic acid and/or vitamin B12.
Characterized by anisocytosis (micro + macrocytosis) and hypo/normochromia.79
 
Iron Deficiency Anemia
Total iron requirement during pregnancy is 1000 mg.
This is mostly needed in second half of pregnancy when daily requirement of iron is 6–7 mg.
Anemia: Microcytic hypochromic.
Diagnosis:
  • MCHC < 30 percent
  • MCV < 75 µm3
  • MCH < 25 pg
  • Decreased serum iron, decreased ferritin, increased TIBC.
Complications:
  1. Pre-eclampsia.
  2. Intercurrent infection
  3. Heart failure
  4. Postpartum hemorrhage.
Prophylaxis: 200 mg FeSO4 (60 mg elemental iron) + 0.5 mg (500 µg) folic acid daily.
Treatment: Tab. Fersolate (FeSO4) 200 mg (60 mg elemental iron) - 1 tab 3 times daily with or after meals.
 
Megaloblastic Anemia
Folate deficiency is the main cause.
Daily requirement during pregnancy – 300 µg (normal 50 µg)
Prophylaxis: 400 µg daily
Treatment: 5 mg oral daily with supplementary iron with or without IM vitamin B12 100 µg/day.
 
Thalassemia
Prenatal diagnosis:
  1. Amniocentesis (between 14–16 weeks) – by amniotic fluid fibroblasts.
  2. Chorion-villus biopsy (between 10–12 weeks) – by trophoblasts.
  3. Cordocentesis (after 18 weeks) – by fetal blood.
    80
 
JAUNDICE IN PREGNANCY
 
Cause
  1. Viral hepatitis – most common (most commonly due to Hepatitis B).
  2. Intrahepatic cholestasis.
  3. Acute fatty liver of pregnancy.
 
Viral Hepatitis
Hepatitis B –
  • Most common cause. (Others – HDV and HCV – in association with HIV).
  • Risk of transmission to fetus – 10 percent in first trimester, 90 percent in third trimester.
  • Chance of transmission is more in HBsAg +ve mother who are also HBeAg +ve.
Mode of transmission – During the time of delivery.
Hepatitis E – Associated with high internal mortality during pregnancy.
 
Intrahepatic Cholestasis
Second most common cause.
Clinical feature:
  • Usually appear in last trimester.
  • Generalized pruritus is the main symptom.
Diagnosis:
  • Bilirubin < 5 mg percent
  • Markedly increased alkaline phosphatase level.
  • Increased AST and ALT (not more than 60 U).
Prognosis: Tends to recur in subsequent pregnancies.
 
Acute Fatty Liver
  • Microvesicular.
Diagnosis:
  • Bilirubin > 10 mg/dl.
  • Increased ALT and AST,
  • Increased PT.
    81
 
THYROTOXICOSIS IN PREGNANCY
Management:
  1. Medical – Propylthiouracil is the drug of choice.
  2. Surgery – thyroidectomy may be done.
    I131 is absolutely contraindicated.
 
GI TRACT
  • There is increased chance of cholesterol gallstones in multiparae.
  • Pregnancy may cause a flare up of symptoms of inflammatory bowel diseases.
  • Acute appendicitis – Laparotomy should be done at the earliest opportunity.
 
RENAL DISEASES
 
Asymptomatic Bacteriuria
Definition: Bacterial count > 105/ml in midstream specimen of urine on two occasions without symptoms of infection.
Incidence: 2–10 percent
Cause: E. coli is the most common organism.
Risk factor: Urinary tract abnormality.
Treatment: Ampicillin 500 mg QID.
Prognosis: Risk of developing chronic renal lesion in later life.
 
Acute Pyelonephritis
Predisposing factors:
  1. Asymptomatic bacteriuria
  2. Abnormality in renal tract.
  3. Stasis of urine.
Causative organism: E. coli (most common).
Note: Renal disorders associated with worst pregnancy outcome are PAN and scleroderma.82
 
INFECTIONS
 
Bacterial
  1. UTI:
    • Most common infection during pregnancy.
    • Most common causative organism is E. coli.
  2. Syphilis: Transplacental transmission can occur at any stage of pregnancy, but more common in early stages.
  3. Gonorrhea: Ophthalmia neonatorum occurs as a result of infection of the fetus during delivery.
  4. Gr. B streptococcus:
    • Most common cause of postpartum bacteremia.
  5. Streptococcus pyogenes: Most common cause of epidemic puerperal sepsis.
 
Viral
  1. CMV – most common cause of congenital viral infection.
  2. Rubella – most serious viral infection in pregnancy, produces maximum congenital abnormalities.
    Most serious and maximum transmission occurs in first trimester (Maximum in first 5-6 weeks).
    Rubella vaccine is contraindicated in pregnancy.
  3. HSV – Mainly HSV II.
    Transmission occurs during delivery.
    Active HSV infection is an indication of elective CS.
    Drug – Acyclovir
    (Indications – Disseminated herpes, Chickenpox in 1st trimester, prophylaxis in recurrent herpes.)
    Neonatal infection may be –
    Disseminated (fatal) or
    Localized (involvement of CNS, eye, mucosa)
  4. HIV –
    Rate of transmission from mother to fetus or infant is 30 percent.
    Routes –
    1. Transplacental transfer
    2. Contaminated secretion and blood during delivery.
    3. Colostrum and breast milk.
      Antibody testing is of limited value in infants.
  5. Hepatitis B – See above.
    83
  6. Chickenpox – Highest risk in case of delivery within 1 week before or after the onset of maternal varicella.
    Varicella zoster causes – cicatrical skin lesions, limb hypoplasia, and rudimentary digits.
 
Protozoal
  1. Toxoplasmosis: 1st trimester – lowest chance of infection but maximum risk of fetal abnormalities.
    3rd trimester – highest chance of transmission but asymptomatic in children.
    The fetus is at risk only if the mother is sero-negative
  2. Malaria:
    Treatment: Chloroquine is the drug of choice.
 
Fungal
  1. Candida albicans: Vulvovaginal candidiasis is more common during pregnancy than non-pregnant state.
    Note: Infections transmitted during delivery –
    1. Gonorrhea
    2. HSV
    3. Hepatitis B.
 
VACCINES
 
Contraindicated in Pregnancy
Live attenuated vaccines - Rubella, Measles, Mumps and Varicella, Meningococcal vaccine, Typhoral.
 
Safe in Pregnancy
Toxoids (TT and DT), Polio, Yellow fever and inactivated vaccines – HBV, Influenza, and Pneumococcal vaccines.
 
Breastfeeding
Is not a contraindication to any vaccine.
 
SLE
  1. Effect of pregnancy on SLE: May flare-up.
  2. Effect of SLE on pregnancy: First trimester abortion, lupus nephritis, recurrent DVT. PIH, prematurity, IUGR, stillbirth.
    84
  3. Effect on neonate – Hemolytic anemia, leukopenia, thrombocytopenia isolated congenital heart block.
 
EPILEPSY
Frequency may be increased in 45 percent cases, mostly in 1st trimester.
 
Treatment
Drugs contraindicated in pregnancy are:
  1. Phenytoin – Produces cleft lip and/or palate, microcephaly, mental retardation, cardiac anomalies, limb defects hypoplasia of the terminal phalanges.
  2. Valproate – Produces neural tube defect.
  3. Carbamazepine – Increased incidence of neural tube defect.
Note: Drug safe in pregnancy is phenobarbitone.
 
Effect of Epilepsy on Pregnancy
More chance of stillbirth.
PUBERTY AND ADOLESCENCE
 
Time Period
  • Puberty – 10–16 years.
  • Adolescence – 10–21 years.
 
PUBERTY
 
Changes during Puberty
In females –
  1. Thelarche (Development of breast) – 10 years.
  2. Puberche (Development of hair) – 11 years.
  3. Adolescent growth spurt
  4. Menarche (First menstruation) - 13 years.
Note: Ability to be pregnant develops 12-24 months after menarche.
  • Maximum growth spurt in girls is seen at menarche.
  • Peak height = Stage III thelarche/puberche.
  • Peak weight = Stage IV thelarche/puberche.
    85
In males –
  • Growth in testicular volume- 11 years.
  • Pubic hair – 12 years.
  • Axillary hair
  • Beard – 16 years.
 
Sexuality
Homosexual experimentation is normal during adole-scence.
 
Precocious Puberty
For girls who show thelarche < 8 years or menarche < 10 years of age (for boys puberty <9 years).
Cause:
  1. Constitutional – most common cause.
  2. Hypothyroidism
  3. Intracranial tumor, trauma, hypothalamic hamartomas.
  4. Gynaecological – Granulosa cell tumor, estrogen or androgen intake.
  5. McCune Albright syndrome
  6. Congenital adrenal hyperplasia – in males.
 
Delayed Puberty
For girls who does not have breast development and/or pubic hair by 13 years or menarche by 16 years.
Causes:
  1. Hypopituitarism
  2. Hypothyroidism
  3. Anorexia nervosa.
 
McCune Albright Syndrome
Precocious puberty, polyostotic fibrous dysplasia, cystic degeneration of long bones, café au lait spots.
 
Adolescent Mortality and Morbidity
  • Most common cause of mortality is violence (especially accidents).
  • Most common cause of morbidity is substance abuse.
    86
 
Medico Legal Aspects
  1. Criminal responsibility:
    Age < 7 years – no responsibility
    <12 years – cannot give valid consent
    >18 years – can give valid consent
  2. Rape –
    Section 375, IPC.
    < 15 years even if she is his own wife, <16 years even with her consent,
  3. Employment –
    The Factories Act, 1948
    < 14 yrs – Cannot be employed
    15–18 yrs- termed as adolescent.
  4. Attainment of majority – 18 years (can cast vote).
  5. Marriage –
    ≥ 18 years in females.
    ≥ 21 years in males.
 
Juvenile Delinquency
Offense by a juvenile defined as:
  • A boy < 16 years or a girl < 18 years.
  • No juvenile can be imprisoned or sentenced to death.
  • They are sent to juvenile homes.
  • Brostal – for boys over 16 years.
GERIATRIC MEDICINE
Geriatric deals with people over 65 years.
 
Biology of Aging
Theories
  1. Pleotrophic antagonism.
  2. Random damage (by free radicals).
  3. Telomer shortening.
  4. Wear-and-tear theory.
 
Changes in Old Age
All are decreased with age except –
  • ADH secretion, body fat, autoantibodies, chondroitin sulphate in cartilages, residual volume, SBP, pulse pressure – increased
  • Not changed with age – Hematocrit.87
 
Diseases of Old Age
  • Most common problem in old age is visual impairment.
  • There is increased incidences of –
    Bone and joint disorders, Cardiovascular disorders, Neurological disorders, Respiratory disorders, Malignancy.
 
Progeria or Accelerated Aging
Seen in –
  • Werner syndrome, Cockayne syndrome, Ataxia telangiectasia, cutis laxa.
 
Epidemiology
  • Population over 65 years in India – 3.8 percent.
Note: Life expectancy at birth in India –
  • Male 62.8 years.
  • Female 63.8 years.