A 45-year-old man with tabes dorsalis is examined. The pupils are small, irregular, and do not constrict to light, but constrict normally during accommodation. This finding is called:

• A Adie pupil
• B Horner syndrome
• C Argyll Robertson pupil ✓
• D Marcus Gunn pupil

Explanation

The Argyll Robertson pupil, classically described as 'accommodates but does not react', is a feature of neurosyphilis, especially tabes dorsalis. The lesion lies in the pretectal region affecting light reflex fibres while sparing accommodation fibres. Adie pupil is a large tonic pupil with light-near dissociation from ciliary ganglion damage, Horner syndrome features miosis with ptosis and anhidrosis, and Marcus Gunn pupil is a relative afferent pupillary defect seen in optic nerve disease.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.