The Dix-Hallpike manoeuvre elicits a geotropic torsional nystagmus with latency of 5 seconds and duration of 15 seconds which fatigues on repeated testing. This is most consistent with:

• A Canalolithiasis of the posterior semicircular canal ✓
• B Cupulolithiasis of the posterior semicircular canal
• C Central positional vertigo
• D Lateral canal BPPV

Explanation

Canalolithiasis of the posterior semicircular canal is the most common cause of BPPV. It produces the classic Dix-Hallpike positional nystagmus: geotropic (upbeating torsional toward the affected ear), latency of 2–20 seconds, duration less than 60 seconds, and fatiguability on repeated testing. Cupulolithiasis of the posterior canal causes non-fatiguing, longer-duration (>1 minute) nystagmus. Central positional vertigo has no latency, no fatigue, and may be purely vertical.

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.