A 40-year-old pilot develops severe vertigo during a flight landing, with inability to stand, vomiting, and horizontal nystagmus fast component beating toward the right ear. Caloric testing during recovery shows canal paresis on the left (>25% asymmetry). The diagnosis is vestibular neuritis. The primary mechanism of damage is thought to be:

• A Vascular occlusion of the anterior vestibular artery causing labyrinthine infarction
• B Viral reactivation (HSV-1) of latent virus in the Scarpa's ganglion causing superior vestibular nerve inflammation ✓
• C Autoimmune demyelination of the vestibular nerve by IgG antibodies
• D Endolymphatic hydrops confined to the vestibular labyrinth

Explanation

Vestibular neuritis (vestibular neuropathy) is thought to be caused predominantly by reactivation of latent Herpes simplex virus type 1 (HSV-1) in the Scarpa's (vestibular) ganglion — the vestibular counterpart of the spiral (auditory) ganglion. Evidence includes: HSV-1 DNA found in 2/3 of vestibular ganglia at autopsy, MRI enhancement of the vestibular nerve in acute cases, and the superiority of corticosteroids over antiviral monotherapy (supporting inflammation over pure viral lysis). The superior vestibular nerve is predominantly affected (hence BPPV later — posterior canal involvement, suggesting superior vestibular nerve damage with utricular otolith dysfunction). Cochlear hearing is preserved since the cochlear nerve is spared.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.