Antidotes: hydrofluoric acid burns: practice question

A Pharmacology 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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Pharmacology · Antidotes: hydrofluoric acid burns

Sample item

A technician spills dilute hydrofluoric acid on his fingers. After an hour he has severe throbbing pain out of proportion to the minimal skin changes. Which local treatment is appropriate?

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

The answer and the reasoning

B. Topical calcium gluconate gel

Fluoride ions penetrate the skin and bind calcium and magnesium, causing deep tissue injury, severe pain and a risk of systemic hypocalcaemia with arrhythmia. Topical calcium gluconate gel supplies calcium to bind free fluoride and relieves the pain, and subcutaneous or intra-arterial calcium may be needed in severe burns. Serum calcium and the ECG are monitored in larger exposures.

Option by option

  • A. Dry gauze dressing with oral analgesics only

    Dry dressing and analgesics leave fluoride unbound and allow deep tissue damage.

  • B. Topical calcium gluconate gel (correct)

    Calcium gluconate provides calcium that binds free fluoride in the tissue.

  • C. Topical sodium bicarbonate paste

    Bicarbonate does not bind fluoride, and neutralisation is not the treatment for hydrofluoric acid.

  • D. Topical silver sulphadiazine only

    Silver sulphadiazine treats burn infection and leaves the fluoride injury untreated.

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 Pharmacology question

What is the answer to this Pharmacology question?

The best answer is B, Topical calcium gluconate gel. Fluoride ions penetrate the skin and bind calcium and magnesium, causing deep tissue injury, severe pain and a risk of systemic hypocalcaemia with arrhythmia.

Why is "Dry gauze dressing with oral analgesics only" not the answer?

Dry dressing and analgesics leave fluoride unbound and allow deep tissue damage.

Why is "Topical sodium bicarbonate paste" not the answer?

Bicarbonate does not bind fluoride, and neutralisation is not the treatment for hydrofluoric acid.

Why is "Topical silver sulphadiazine only" not the answer?

Silver sulphadiazine treats burn infection and leaves the fluoride injury untreated.

What concept does this question test?

It tests Antidotes: hydrofluoric acid burns in Pharmacology. Topical calcium gluconate gel supplies calcium to bind free fluoride and relieves the pain, and subcutaneous or intra-arterial calcium may be needed in severe burns. Serum calcium and the ECG are monitored in larger exposures.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Antidotes: hydrofluoric acid burns?

Learn drugs as classes, then the exception in each class that an examiner would pick. Then use the flashcards and the other Pharmacology 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.