Which statement best describes Horner syndrome education?

• A. Horner syndrome presents with lid droop and a small pupil and requires imaging to rule out serious causes
• B. It presents with large pupils and no ptosis
• C. It is always due to eye infections
• D. It only affects one eye and never changes

Answer: (A)

Horner syndrome is about disruption of the sympathetic nerves to the eye, which produces a characteristic set of signs: the affected eyelid appears a bit droopy (ptosis) and the pupil on that side is smaller (miosis). Because this neuro-vascular pathway can be involved by serious conditions—such as carotid artery dissection or a tumor at the lung apex (Pancoast tumor)—it's important to image to identify the underlying cause. So the statement that Horner presents with lid droop and a small pupil and that imaging is needed to rule out serious causes best captures both the typical eye findings and the essential workup.

The other descriptions don’t fit Horner. Large pupils with no ptosis would point away from Horner; eye infections aren’t the usual cause; and Horner is typically unilateral rather than never changing (though bilateral cases exist less commonly).