A 35-year-old patient has unidirectional horizontal nystagmus increasing on gaze toward the fast phase, direction-changing nystagmus on positional testing, and a positive Fukuda stepping test. These findings are MOST consistent with:

• A Central vestibular lesion (cerebellar or brainstem) ✓
• B Benign paroxysmal positional vertigo (BPPV) of the posterior canal
• C Peripheral vestibular hypofunction (unilateral vestibular neuritis)
• D Horizontal canal BPPV (canalith repositioning of horizontal canal)

Explanation

Direction-changing nystagmus on positional testing (geotropic or apogeotropic alternating with head turns) along with nystagmus that increases on gaze toward the fast phase (gaze-evoked nystagmus) and a positive Fukuda test suggests a central vestibular pathology. Peripheral lesions produce unidirectional nystagmus that increases on gaze away from the lesion (Alexander's law, beating toward the intact side). BPPV produces transient positional nystagmus that fatigues, not persistent direction-changing nystagmus.

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.