Nutrition: pellagra: practice question

A PSM 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.

Try it

PSM · Nutrition: pellagra

Sample item

A 40-year-old farm labourer, whose staple is jowar (sorghum), presents with a symmetric rash on sun-exposed skin of the neck and forearms, chronic diarrhoea and recent memory loss. Which deficiency is most likely?

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

The answer and the reasoning

B. Niacin

The triad of photosensitive dermatitis, diarrhoea and dementia indicates pellagra, caused by niacin deficiency. It occurs in populations dependent on maize or jowar, in which niacin is bound and the excess leucine in jowar interferes with conversion of tryptophan to niacin. Treatment is nicotinamide with a balanced diet.

Option by option

  • A. Thiamine

    Thiamine deficiency causes beriberi, with neuropathy or cardiac failure, and Wernicke encephalopathy.

  • B. Niacin (correct)

    Correct. Dermatitis, diarrhoea and dementia in a jowar eater indicate niacin deficiency.

  • C. Riboflavin

    Riboflavin deficiency causes angular stomatitis, glossitis and cheilosis rather than photosensitive dermatitis.

  • D. Vitamin B12

    Vitamin B12 deficiency causes megaloblastic anaemia and subacute combined degeneration, without a photosensitive rash.

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.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is B, Niacin. The triad of photosensitive dermatitis, diarrhoea and dementia indicates pellagra, caused by niacin deficiency.

Why is "Thiamine" not the answer?

Thiamine deficiency causes beriberi, with neuropathy or cardiac failure, and Wernicke encephalopathy.

Why is "Riboflavin" not the answer?

Riboflavin deficiency causes angular stomatitis, glossitis and cheilosis rather than photosensitive dermatitis.

Why is "Vitamin B12" not the answer?

Vitamin B12 deficiency causes megaloblastic anaemia and subacute combined degeneration, without a photosensitive rash.

What concept does this question test?

It tests Nutrition: pellagra in PSM. It occurs in populations dependent on maize or jowar, in which niacin is bound and the excess leucine in jowar interferes with conversion of tryptophan to niacin. Treatment is nicotinamide with a balanced diet.

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 Nutrition: pellagra?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.