Section I
Neonatology
A female infant born at 28 weeks of gestation was admitted in the NICU. She was born to a 28 year old para 2, gravida 2 mother after Lscs, because of bad obstetric history of placenta previa and abruptio placenta. There was acute fetal bradycardia of 42/min. Amniotic fluid was meconium stained and the umbilical cord was also stained. Apgar scar was 3 at five minutes. Umbilical cord blood gases showed pH 6.8 and Pco2 of 82 mmHg. Weight of the child was 750 gms and length 37 cms and head circumference 26 cms, all between the 19th and 25th percentiles. The baby had clonic movements of the limbs and subtle seizures on the 1st day. She was intubated and resuscitated and IV Lorazepam and Pheyotin sodium was started. Convulsions did not recur, but the infant had marked hypotonia, for the next three days. She developed heperbilirubinemia, pneumonia and hyponatremia. She was ventilated for four days. She developed hypertonia intermittently in the limbs. At eleven days she had poor respiratory effort, lateral and downward deviation of both eyes, facial weakness and absent corneal reflexes.
Questions
- What is the line of management ?
- What are the likely complications in this case?
- What are the essential investigations that are required?
- What are the likely neurological complications in this infant?
She became dependant on oxygen, and developed hypertonia and hypreflexic intermittently, neonatal reflexes were abnormal, had feeding difficulties and infrequent subtle seizures. She expired at the age of 35 days.
She was maintained on the maintainance IV fluids, maintenance phenytoin, oxygen, gavage feeding and multivitamin and calcium supplementation. The investigations done were 1) EEG, 2) CT scan of the brain, 3) Brain stem evoked potentials, 4) Opthamoscopy, 5) CRP test, 6) Serum Electrolytes, Serum Ca and repeated blood glucose tests.
Opthamological examination showed immature retina. Brianstem evoked potentials showed no transmission through brain stem. EEG was appropriate for the age. Serum Ca. was normal, blood glucose once showed 40 mg%.
Discussion
The differential diagnosis of neonatal seizures are Hypoxic/Ischemic encephalopathy/Intracranial hemorrhage or infection metabolic abnormalities of glucose, calcium, magnesium, sodium. Organic aminoacidopathy/Pyridoxine deficiency/Maternal drug withdrawal. Differential diagnosis of facial weakness include the following conditions. Cerebral disease/Mobius syndrome, Facial nerve injury, Traumatic compression by hemotoma. Neuromuscular junction disease/Myasthenia gravis/Botulism. Muscle disease: Congenital myotonic dystrophy/muscular dystrophy/Structural myopathy/Mitochondrial myopathy/Hypoplasia of depressor anguli oris muscle.
In this infant a diagnosis of acute on chronic hypoxic ischemic injury was made. It had affected the nervous system including the bilateral cerebral cortex, multiple cranial nerve nuclei including 3rd, 7th and the 8th nerves and anterior horn cells in the spinal cord transiently. There was evidence of brain dysfunction seen as variability of tone in muscle abnormal brain stem evoked responses. Death may be due the effects of HIE on lungs and cerebral function. The biochemical disturbances were metabolic acidosis, hypercarbia and hypoxia.
Pathological Findings and Discussion
Placenta in this case showed immature chorionic villi, severe acute chorioamnionitis and the disruption of posterior circulation.
Brain lissencephalic like cerebral cortex, reflecting immaturity. Cranial nerve roots v1, v11 and v111 nerves not identified. Indistinct demarcation between white and gray matter. Cerebellum was hypoplastic astrocytes and neuronal loss. Spinal cord gross exam was normal (Figs 1.1 to 1.4).
Microscopic Examination
Extensive gliosis placenta previa with reactive astrocytes and neuronal loss, predominantly in the periventricular gray matter. There was neuronal loss in cranial nerve nuclei 3, 7, 8 and 12 in the anterior limb of the oliver nucleus. Cerebellar cortex showed diffuse marked gliosis an no significant loss of Purkinje cells. Section of skeletal muscle (quadriceps) showed diffuse muscle atrophy consistent with ischemic/hypoxic dmage of anterior horn cells of spinal cord.
Impression
Hypoxic/Ischemia in the distribution of posterior circulation and involvement of tegmentum.
Mobius syndrome was first described by van Graefe in 1880: Congenital facial diplegia with or without other cranial nerve palsies and limb abnormalities.
Autosomal dominant, autosomal recessive and X-linked recessive inheritance are proposed. Familial gene loci map to 3q21-22, 10q21, 13q 12.2 and 1p22.3
Brainstem segmental necrosis and proposed ischemia and infection are probable etiologic factors, the current case included many risk factors like ischemia, premature birth, placenta previa, abruptio placenta acute chorioamnionitis.
In 1986 Bavinck and Weaver proposed subclavian artery supply disruption. Sequence as a hypothesis of a vascular cause of mobius syndrome. Between 37–42 wks blood supply of hind brain changes from carotid supply to vertebral supply. As formation or obstruction of primitive trigeminal arteries regress and basilar arterial flow reverses direction creating a potential watershed zone. Mobius anomaly may result from premature regression of tigeminal arteries and/or delayed formation or obstruction in the basilar or vertebral arteries.4
Hypoxic-ischemia of child CNS that occurs first trimester (5–6 weeks). Placental insufficiency during this period could produce hypoxic ischemic injury of the hind brain.
Volpe
Nervous System development in premature infants:
- Blink at light at 26 weeks
- Persistently close the eyes to a light stimulus at 32 weeks
- Track and object at 34 weeks
- Turn eyes to soft light at 37 weeks
- Pupillary light reaction at 30 weeks
- Dolls eye maneuver full range of eye movements by 25 weeks
- Spontaneous roving eye movements at 32 weeks
- Auditory system becomes functional by 28 weeks
- Swallowing begins by 11 weeeks
- Sucking and swallowing becomes coordinated by 28 weeks
- Sucking, swallowing and breathing becomes coordinated by 32 weeks
- Muscle tone: Minimal resistance to passive movements before 30 weeks
- Lower limbs flexor tone becomes strong by 36 weeks
- Full flexor tone in all limbs by 40 weeks
- Hand plamar reflex by 28 weeks, fully present by 32 weeks and strong enough to support lifting by 37 weeks
- Alert response to stimulation by 28 weeks
- Spontaneous arousal by 32 weeks
- Increasingly alert with vigorous cry by 36 weeks.
Acknowledgement
I am thankful to Dr. Ananta Manepally, St Louts, USA for the guidance.
BIBLIOGRAPHY
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