Leprosy: morphological index: practice question

A Dermatology 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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Dermatology · Leprosy: morphological index

Sample item

What does the morphological index (MI) measure in leprosy?

AThe percentage of solid-staining bacilli, reflecting viable organismsBThe thickness of affected nervesCThe number of skin lesionsDThe total bacillary load on a 0 to 6 logarithmic scale

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

The answer and the reasoning

A. The percentage of solid-staining bacilli, reflecting viable organisms

The morphological index is the percentage of uniformly stained (solid) bacilli among those counted in a smear, and these represent viable organisms. It falls quickly with effective multidrug therapy, before the bacteriological index declines. The bacteriological index is the logarithmic measure of total bacillary load.

Option by option

A. The percentage of solid-staining bacilli, reflecting viable organisms (correct)
Correct. MI is the percentage of solid-staining viable bacilli.
B. The thickness of affected nerves
Nerve thickness is a clinical finding, not a smear index.
C. The number of skin lesions
Lesion counts are used in operational classification.
D. The total bacillary load on a 0 to 6 logarithmic scale
That describes the bacteriological index.

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.

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is A, The percentage of solid-staining bacilli, reflecting viable organisms. The morphological index is the percentage of uniformly stained (solid) bacilli among those counted in a smear, and these represent viable organisms.

Why is "The thickness of affected nerves" not the answer?

Nerve thickness is a clinical finding, not a smear index.

Why is "The number of skin lesions" not the answer?

Lesion counts are used in operational classification.

Why is "The total bacillary load on a 0 to 6 logarithmic scale" not the answer?

That describes the bacteriological index.

What concept does this question test?

It tests Leprosy: morphological index in Dermatology. It falls quickly with effective multidrug therapy, before the bacteriological index declines. The bacteriological index is the logarithmic measure of total bacillary load.

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 Leprosy: morphological index?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology 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.