A 28-year-old woman presents with a 6-week history of bilateral eye pain, photophobia, and blurred vision. Slit-lamp examination reveals bilateral interstitial keratitis with deep stromal infiltrates and corneal edema. Two weeks after ocular symptom onset, she developed acute severe vertigo with tinnitus and aural fullness lasting 3 days, followed by progressive hearing loss. Audiometry shows the pattern marked **A** in the diagram. Serologic tests for syphilis (FTA-ABS, RPR) are negative. Which of the following is the most likely diagnosis?
A. Cogan syndrome with autoimmune-mediated vestibulocochlear dysfunction
B. Syphilitic interstitial keratitis with secondary otosyphilis
C. Susac syndrome with retinal artery occlusions and encephalopathy
D. Granulomatosis with polyangiitis (GPA) with upper respiratory tract involvement
Explanation
Why Cogan syndrome with autoimmune-mediated vestibulocochlear dysfunction is right
Cogan syndrome is a rare autoimmune vasculitis characterized by the pathognomonic dyad of non-syphilitic interstitial keratitis and vestibulocochlear dysfunction (Ménière-like episodes with bilateral sensorineural hearing loss). The clinical presentation—young adult female, bilateral interstitial keratitis with stromal infiltrates, followed within weeks by acute vertigo with tinnitus and progressive bilateral SNHL shown as the pattern marked A (bilateral severe down-sloping SNHL)—is classic for Cogan syndrome. The negative syphilis serology excludes the most important mimicker. The pathogenesis involves autoimmune-mediated vasculitis of small-to-medium-sized arteries with cross-reacting autoantibodies against shared antigens of corneal and inner ear endothelium, explaining the simultaneous ocular and audiovestibular involvement. Harrison's and Cummings both emphasize that the bilateral asymmetric SNHL pattern is characteristic and often becomes severe-to-profound within months despite therapy.
Why each distractor is wrong
Syphilitic interstitial keratitis with secondary otosyphilis: Although syphilis classically presents with interstitial keratitis and can cause hearing loss, the negative FTA-ABS and RPR serologies definitively exclude active or latent syphilis. Syphilitic hearing loss is typically conductive or mixed, not the bilateral severe down-sloping SNHL pattern shown in A.
Susac syndrome with retinal artery occlusions and encephalopathy: Susac syndrome is a microvasculitis affecting the retina, cochlea, and brain; it presents with retinal artery branch occlusions (not interstitial keratitis), encephalopathy, and hearing loss. The absence of retinal findings and neurologic symptoms, combined with the characteristic interstitial keratitis, makes Susac syndrome unlikely.
Granulomatosis with polyangiitis (GPA) with upper respiratory tract involvement: GPA is a systemic necrotizing vasculitis that can involve the upper respiratory tract and cause hearing loss, but it does not classically present with interstitial keratitis. GPA typically causes scleritis or other anterior uveitis, not the deep stromal infiltrates of interstitial keratitis seen here.
High-YieldNEET PG
Cogan syndrome = non-syphilitic interstitial keratitis + Ménière-like vestibulocochlear dysfunction in a young adult; always rule out syphilis first; bilateral SNHL often becomes severe-to-profound and requires urgent high-dose systemic corticosteroids.
