Paediatric emergencies: tricyclic antidepressant poisoning: practice question

A Pediatrics question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pediatrics · Paediatric emergencies: tricyclic antidepressant poisoning

Sample item

A 2-year-old is brought drowsy after ingesting her grandmother's tablets. She has dilated pupils, dry mucosa, tachycardia, a sudden generalised seizure and an ECG with QRS duration of 140 ms. Which drug should be given?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Intravenous sodium bicarbonate

The anticholinergic features with seizures and QRS widening indicate tricyclic antidepressant toxicity from sodium channel blockade. Sodium bicarbonate boluses narrow the QRS and treat arrhythmias and hypotension by raising serum sodium and pH.

Option by option

  • A. Intravenous physostigmine

    Physostigmine can precipitate seizures and asystole in tricyclic poisoning and is avoided.

  • B. Intravenous sodium bicarbonate (correct)

    Correct. Sodium bicarbonate reverses sodium channel blockade and narrows the QRS.

  • C. Intravenous flumazenil

    Flumazenil can provoke seizures in tricyclic ingestion and is contraindicated.

  • D. Intravenous procainamide

    Procainamide is a class Ia sodium channel blocker and would worsen conduction block.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is B, Intravenous sodium bicarbonate. The anticholinergic features with seizures and QRS widening indicate tricyclic antidepressant toxicity from sodium channel blockade.

Why is "Intravenous physostigmine" not the answer?

Physostigmine can precipitate seizures and asystole in tricyclic poisoning and is avoided.

Why is "Intravenous flumazenil" not the answer?

Flumazenil can provoke seizures in tricyclic ingestion and is contraindicated.

Why is "Intravenous procainamide" not the answer?

Procainamide is a class Ia sodium channel blocker and would worsen conduction block.

What concept does this question test?

It tests Paediatric emergencies: tricyclic antidepressant poisoning in Pediatrics. Sodium bicarbonate boluses narrow the QRS and treat arrhythmias and hypotension by raising serum sodium and pH.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Paediatric emergencies: tricyclic antidepressant poisoning?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.