Mood disorders: mild lithium toxicity: practice question

A Psychiatry 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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Psychiatry · Mood disorders: mild lithium toxicity

Sample item

A man on long-term lithium has had severe diarrhoea and vomiting for two days. He has nausea, coarse tremor and mild unsteadiness, is alert, and his serum lithium is 1.7 mmol/L. What is the best immediate management?

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

The answer and the reasoning

D. Withhold lithium and give intravenous isotonic saline

Dehydration reduces lithium clearance and raises the level. Mild to moderate toxicity without severe neurological features is managed by stopping lithium, restoring fluids and electrolytes with saline, and monitoring levels. Dialysis is reserved for very high levels, severe neurological signs or renal failure.

Option by option

  • A. Start haemodialysis immediately

    Haemodialysis is kept for severe toxicity, very high levels or poor renal function.

  • B. Give furosemide to force diuresis

    Loop diuretics add volume depletion and can further raise lithium levels.

  • C. Give activated charcoal and continue lithium

    Activated charcoal does not bind lithium, and continuing it would worsen toxicity.

  • D. Withhold lithium and give intravenous isotonic saline (correct)

    Correct. Stop lithium and rehydrate with saline, with repeat levels, for mild to moderate toxicity.

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 Psychiatry question

What is the answer to this Psychiatry question?

The best answer is D, Withhold lithium and give intravenous isotonic saline. Dehydration reduces lithium clearance and raises the level.

Why is "Start haemodialysis immediately" not the answer?

Haemodialysis is kept for severe toxicity, very high levels or poor renal function.

Why is "Give furosemide to force diuresis" not the answer?

Loop diuretics add volume depletion and can further raise lithium levels.

Why is "Give activated charcoal and continue lithium" not the answer?

Activated charcoal does not bind lithium, and continuing it would worsen toxicity.

What concept does this question test?

It tests Mood disorders: mild lithium toxicity in Psychiatry. Mild to moderate toxicity without severe neurological features is managed by stopping lithium, restoring fluids and electrolytes with saline, and monitoring levels. Dialysis is reserved for very high levels, severe neurological signs or renal failure.

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 Mood disorders: mild lithium toxicity?

Learn each diagnosis by its core features and its first-line treatment. Then use the flashcards and the other Psychiatry 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.