Fast Facts in Childhood Poisoning Sumitha Nayak
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1General Principles2

General Principles for Treatment of Childhood PoisoningChapter 1

Toxin ingestion may be intentional, especially in teenagers and adolescents or accidental in toddlers and younger children. Intentional ingestion is usually with multiple substances, hence the signs and symptoms may not be typical of any particular substance. It could also vary depending on whether it was consumed on an empty stomach or after food, as absorption can vary when there is food in the stomach. Also, the hyperactive children, those with pre-existing neurological problems and those with pre-existing diseases, may show exaggerated signs.
 
INITIAL ASSESSMENT
When a child with a suspected poisoning is brought in, it is essential to first stabilize the patient and then attempt to find out what poison had been ingested. Take into consideration all the possible substances, over-the-counter (OTC) medications and drugs that could have been brought in by any visitors to the home. All medications should be seen, preferably in the original containers or packs. The type of poison, agents and specific antidotes are given in Table 1.1.
 
Emergency Stabilization of the Patient
 
Check and Stabilize
  1. Airway: Ensure that the airway is clear and clean, free from any ingested matter, vomitus of other obstructions. If essential, place a mouth gag to prevent damage to the tongue and teeth.
  2. Breathing: Ensure that the patient is breathing comfortably. Administer supplemental oxygen to ensure adequate tissue perfusion.
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    Table 1.1   Specific antidotes
    Type of poison
    Agent
    Antidote
    Acetaminophen
    Acetaminophen
    N-acetylcysteine
    Anticoagulant
    Warfarin, rat poison
    Vitamin K
    Cardiac drugs
    Beta blockers, digoxin, calcium channel blockers
    Calcium chloride, glucagon
    Cholinergic—muscarinic, nicotinic
    Organophosphates, some mushrooms
    Atropine, Pralidoxime
    Ethylene glycol
    Antifreeze
    Ethanol
    Hydrogen sulfide
    Industrial gas leaks
    Sodium nitrite
    Iron
    Iron containing products
    Deferoxamine
    Opioid
    Opioid
    Naloxone
    Lead
    Lead containing products
    Dimercaptosuccinic acid (DMSA), D-penicillamine
    Mercury
    Mercury containing products
    DMSA, British anti-Lewisite (BAL), D-penicillamine
    Naphtha
    Napthalene balls
    Methylene blue
    Arsenic
    Arsenic compounds, contaminated fish
    BAL, DMSA
  3. Circulatory status to be noted. Intravenous (IV) access to be obtained immediately, to facilitate administration of fluids and drugs before circulatory collapse or compromise occurs.
  4. Obtain a random blood sugar level, especially in those who have altered mental status or with signs of hypoglycemia. When the blood sugar level is lower than 80 mg/dL(4.4 mmol/L), it is essential to administer IV glucose rapidly to reverse the signs.
    • Dose: Infants: 5 mL/kg of 10% dextrose.
      • Children: 4 mL/kg of 25% dextrose.
  5. Intravenous thiamine is recommended to be administered, before the dextrose infusion, to prevent the occurrence of Wernicke's encephalopathy.
    • Dose: Infants: 10 mg.
      • Children: 10–25 mg.
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  6. Pulse oximetry, especially in those with altered mental status will help to guide the oxygen supplementation that has to be administered.
  7. Electrocardiogram (ECG) in all leads is essential as a base- line, before the start of cardiac monitoring. It also gives information regarding any cardiotoxic effects of the ingested substance.
  8. Watch out for ‘toxidromes’ the symptoms that could point to particular toxin exposure. Observe the breath for any characteristic odors, which can lead to a diagnosis about the toxin.
  9. Removal of the poison—if it is present around the mouth, on the skin or as vomitus, it must be washed out with copious water and all external traces of the poison must be removed.
 
Points to Note
  1. The typical textbook presentations of each toxicity may not be present in every patient. Hence, a strong index of suspicion is essential to make an accurate diagnosis and successful treatment of the patient.
  2. Adolescents and older children who have intentionally consumed poisons, usually take a combination of substances. Here, again the presentations vary and poses a challenge for diagnosis.
  3. Every child who has consumed a toxin, whether accidentally or intentionally needs to be counseled and closely monitored after recovery, so that there is no repetition, as well as any associated or underlying comorbidities are corrected at the earliest.
  4. Ensure that all persons who are closely associated with the child, especially the immediate family are made aware of the seriousness of the situation and cooperate to ensure that the child is not exposed to the toxins again.
  5. Counseling of the parents and family members is essential to sensitize them to the gravity of the issue at hand.
  6. Wherever possible, use of childproof or tamper-proof medicine bottles, is to be encouraged. Parents and caregivers are encouraged to keep their medications out of reach of children, especially the toddlers.
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  7. Parents must never administer medications to the child by telling them, it is a candy or a sweet, which makes the younger children desire to consume it in larger quantities.
 
Laboratory Tests
Tests will help to corroborate the clinical diagnosis, while at the same time, assess the patient's clinical status during the course of stay in the hospital (Table 1.2).
Table 1.2   Different laboratory tests to corroborate clinical diagnosis
Laboratory tests
Clinical diagnosis
Blood glucose
Ingestion of hypoglycemic agents
Serum bicarbonate
Renal failure
Acidosis
Serum electrolyte
Electrolyte imbalance
Renal failure
Pulse oximetry
Hypoxia
ECG in all leads
Cardiotoxicity
Prothrombin time, coagulation profile
Coagulopathy
Urinalysis
Renal failure
Arterial blood gas
Hypoxemia
Urine drug screen
Specific drug ingestion
 
Supportive Treatment
The treatment of poisonings in children follow confirmed and time-tested patterns, with the recommendations for induced emesis and gastric decontamination forming the basis of therapy. However, nowadays, the role of induced emesis is limited, as it has not been found to improve the patient outcome. The use of emetics like syrup of ipecac has been long abandoned by the American Academy of Pediatrics, as well as the European and American Toxicology Committees. It has not been found to improve the patient's condition, even if administered within few minutes of toxin consumption.
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Gastric Decontamination
Gastric lavage has been used as the method to remove the ingested toxins from the stomach. It has maximal benefits, when it is done as soon as possible, generally within 1 hour after toxin ingestion. A relatively large bore orogastric tube is inserted and normal saline is administered. The contents are withdrawn immediately using a large syringe and the input must match the output. The wash is usually continued, until the solution is clear. The risks associated with gastric lavage are:
  • Esophageal trauma
  • Laryngeal trauma
  • Aspiration
  • Nausea, vomiting
  • Impairment of the level of consciousness.
Contraindications to gastric lavage are illustrated in Figure 1.1.
 
Adsorption Agents
Activated charcoal is used to decrease the absorption of ingested toxins from the stomach. It is useful in cases of poisoning with dapsone, phenobarbital, theophylline, salicylates, phenytoin, valproic acid, carbamazepine or quinine.
Activated charcoal acts by decreasing the enterohepatic and the enteroenteric recirculation of the ingested drugs, which usually occurs in the gut lumen. However, not all the drugs are well adsorbed by this agent and hence, it's usefulness may be limited in children. The color and consistency are other deterrents in their usefulness in childhood poisonings.
When indicated, it is recommended to administer activated charcoal as soon as possible after toxin ingestion, preferably within 1 hour. The first dose is generally administered along with sorbitol, which improves the taste, as well as the transit through the gastrointestinal tract (GIT), as it is a cathartic agent. Subsequent doses do not need to be administered along with sorbitol as it can give rise to severe fluid and electrolyte imbalances.
Dose recommended in children: 1–2 g/kg body weight, in cases of unknown quantity of drug ingestion. When the ingested amount can be determined, a 10:1 charcoal-drug ratio needs to be administered for the desired effects.
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zoom view
Fig. 1.1: Contraindications to gastric lavage (GI, gastrointestinal)
 
Cathartics
Cathartics are administered with the presumption that they can aid the movement of the toxic agent through the GIT and hence assist in the excretion from the system. However, the role of cathartics in children is doubtful due to the risk of electrolyte and fluid imbalances, which can cause major complications to the existing toxicity. Sorbitol is a cathartic, which is usually used along with the initial dose of activated charcoal in a dose of 1–2 g/kg body weight.
Polyethylene glycol is another cathartic agent, which is used for whole bowel irrigation following toxicity. It is used in cases of poisoning with sustained release drug preparations or in case of heavy metal toxicity. However, it has a limited role in childhood poisoning.
 
Emetics
Following the ingestion of toxins, the attempt used to be made to expel the toxin by inducing vomiting, in an attempt to decrease the amount of ingested toxin. However, the administration of emetic agents like syrup of ipecac is no longer recommended, as it has not been found to produce any beneficial effects in children, but may pose a danger of aspiration in case of unprotected airways.
 
Urine Alkalinization and Hemodialysis
Excretion of certain toxins can be accelerated via the urinary route. In these cases, by changing the urine pH, it is possible to aid the drug excretion. For example, methotrexate, etc.9
Urinary alkalinization is useful in cases of toxicity with salicylates, tricyclic antidepressants, phenobarbital. This is done by administering IV fluids, usually half normal saline to which 50–150 mEq of sodium bicarbonate has been added per liter, to result in an isotonic fluid. The rate of administration is 1–2 L/h. After adequate urine output has been established, KCl is added in a dose of 20–40 mEq/L. The urine pH must be maintained from 7.5 to 8.5.
Hemodialysis involves the circulation of the blood through an extracorporeal membrane and is indicated in cases, where the patient's condition is rapidly deteriorating when the endogenous clearance of the drug is low or when massive amounts of drug ingestion has taken place.
Hemodialysis is useful in cases of toxicity with salicylates, theophylline, phenobarbital, methanol or valproic acid.
Hemoperfusion involves the passage of the blood through an extracorporeal membrane, which contains an adsorbent like activated charcoal or polystyrene resin. As the thin membrane has a larger surface area, there is more drug adhesion and excretion from the circulation.
SUGGESTED READING
  1. Kleigman RM, Behrman RE, Jenson HB, et al. Nelson Textbook of Pediatrics, 18th edition. Elsevier Health Sciences Division;  2007.
  1. McGregor T, Parkar M, Roa S. Evaluation and management of common childhood poisonings. Am Fam Physician. 2009 Mar;79(5):397–403.