Neuro-ophthalmology: 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.

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Ophthalmology · Neuro-ophthalmology

Sample item

A smoker with shoulder pain from an apical lung tumour (Pancoast tumour) has mild ptosis, a small pupil and reduced sweating on the same side of the face. Which structure is interrupted?

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

The answer and the reasoning

A. Oculosympathetic pathway at the cervical sympathetic chain

Horner syndrome results from interruption of the sympathetic supply to the eye, causing miosis, mild ptosis and anhidrosis. A lung apex tumour can invade the cervical sympathetic chain and stellate ganglion at the thoracic inlet.

Option by option

  • A. Oculosympathetic pathway at the cervical sympathetic chain (correct)

    Damage to the sympathetic chain causes the triad of miosis, ptosis and facial anhidrosis.

  • B. Oculomotor nerve in the cavernous sinus

    Oculomotor involvement would give a dilated pupil and severe ptosis with the eye deviated down and out.

  • C. Facial nerve in the parotid gland

    Facial nerve palsy causes inability to close the eye and weakness of facial muscles, not a small pupil.

  • D. Optic nerve at the chiasm

    Chiasmal damage causes visual field loss and not pupil and lid changes.

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 A, Oculosympathetic pathway at the cervical sympathetic chain. Horner syndrome results from interruption of the sympathetic supply to the eye, causing miosis, mild ptosis and anhidrosis.

Why is "Oculomotor nerve in the cavernous sinus" not the answer?

Oculomotor involvement would give a dilated pupil and severe ptosis with the eye deviated down and out.

Why is "Facial nerve in the parotid gland" not the answer?

Facial nerve palsy causes inability to close the eye and weakness of facial muscles, not a small pupil.

Why is "Optic nerve at the chiasm" not the answer?

Chiasmal damage causes visual field loss and not pupil and lid changes.

What concept does this question test?

It tests Neuro-ophthalmology in Ophthalmology. A lung apex tumour can invade the cervical sympathetic chain and stellate ganglion at the thoracic inlet.

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 Neuro-ophthalmology?

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.