Thyroid drugs: myxoedema coma: 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 · Thyroid drugs: myxoedema coma

Sample item

A 70-year-old woman is brought in during winter with hypothermia 32 degrees Celsius, bradycardia, hyponatraemia and unresponsiveness. Her TSH is above 100 mU/L and free T4 is undetectable. Which treatment is most appropriate?

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

The answer and the reasoning

B. Intravenous levothyroxine with intravenous hydrocortisone

Myxoedema coma is life-threatening decompensated hypothyroidism needing intravenous levothyroxine, because gut absorption is unreliable. Intravenous hydrocortisone is given with it to cover possible coexisting adrenal insufficiency and the increased cortisol clearance that thyroxine causes. Rapid external rewarming can cause vasodilation and circulatory collapse, so passive warming is used.

Option by option

  • A. Oral levothyroxine alone

    Oral levothyroxine is poorly absorbed in myxoedematous gut and acts too slowly in coma.

  • B. Intravenous levothyroxine with intravenous hydrocortisone (correct)

    Intravenous thyroid hormone replaces the deficit, and hydrocortisone covers adrenal insufficiency.

  • C. Radioactive iodine

    Radioactive iodine is a treatment for hyperthyroidism and would worsen hypothyroidism.

  • D. Rapid active external rewarming

    Rapid active rewarming risks peripheral vasodilation and hypotension; passive warming is preferred.

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, Intravenous levothyroxine with intravenous hydrocortisone. Myxoedema coma is life-threatening decompensated hypothyroidism needing intravenous levothyroxine, because gut absorption is unreliable.

Why is "Oral levothyroxine alone" not the answer?

Oral levothyroxine is poorly absorbed in myxoedematous gut and acts too slowly in coma.

Why is "Radioactive iodine" not the answer?

Radioactive iodine is a treatment for hyperthyroidism and would worsen hypothyroidism.

Why is "Rapid active external rewarming" not the answer?

Rapid active rewarming risks peripheral vasodilation and hypotension; passive warming is preferred.

What concept does this question test?

It tests Thyroid drugs: myxoedema coma in Pharmacology. Intravenous hydrocortisone is given with it to cover possible coexisting adrenal insufficiency and the increased cortisol clearance that thyroxine causes. Rapid external rewarming can cause vasodilation and circulatory collapse, so passive warming is used.

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 Thyroid drugs: myxoedema coma?

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.