Neuro: Horner syndrome cocaine test: practice question

A Ophthalmology 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

Ophthalmology · Neuro: Horner syndrome cocaine test

Sample item

A patient has ptosis, miosis and anhidrosis on the left. After instilling 4 percent cocaine, the left pupil fails to dilate. What does this indicate?

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

The answer and the reasoning

C. Confirms Horner syndrome of any level

Cocaine blocks norepinephrine reuptake, and dilates a normal pupil but not one denervated of sympathetic supply, regardless of the site of the lesion. Hydroxyamphetamine then distinguishes postganglionic from pre-ganglionic lesions. Apraclonidine is a newer test.

Option by option

  • A. Localises to a third order lesion only

    Hydroxyamphetamine is used for localisation, not cocaine.

  • B. Excludes Horner syndrome

    A normal pupil would dilate.

  • C. Confirms Horner syndrome of any level (correct)

    Correct. Failure to dilate confirms Horner syndrome.

  • D. Localises to a preganglionic lesion only

    Cocaine does not localise the lesion.

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 Ophthalmology questions

Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is C, Confirms Horner syndrome of any level. Cocaine blocks norepinephrine reuptake, and dilates a normal pupil but not one denervated of sympathetic supply, regardless of the site of the lesion.

Why is "Localises to a third order lesion only" not the answer?

Hydroxyamphetamine is used for localisation, not cocaine.

Why is "Excludes Horner syndrome" not the answer?

A normal pupil would dilate.

Why is "Localises to a preganglionic lesion only" not the answer?

Cocaine does not localise the lesion.

What concept does this question test?

It tests Neuro: Horner syndrome cocaine test in Ophthalmology. Hydroxyamphetamine then distinguishes postganglionic from pre-ganglionic lesions. Apraclonidine is a newer test.

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 Neuro: Horner syndrome cocaine test?

Group the red eye by what to examine and what the pupil does. Then use the flashcards and the other Ophthalmology 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.