Atypical PC-BPPV - Cupulolithiasis and Short-Arm Canalithiasis: A Retrospective Observational Study

Atypical posterior canal (pc) benign paroxysmal positional vertigo (BPPV) may be caused by cupulolithiasis (cu), short arm canalithiasis (ca), or jam. The purpose of this study was to describe the clinical presentation and differential diagnosis of pc-BPPV-cu and short arm canalithiasis.

This retrospective observation study identified persons with atypical pc-BPPV based on history and findings from four positional tests. Patterns of nystagmus suggested canal involved and mechanism of BPPV. Interventions included canalith repositioning procedures (CRP).

Fifteen persons, 17 episodes of care, met inclusion criteria, 65% referred following unsuccessful CRPs. Symptoms included persistent, non-positional unsteadiness, "floating" sensation, with half experiencing nausea/vomiting. Downbeat nystagmus with/without torsion in Dix-Hallpike (DH) and Straight Head Hang (SHH) position and no nystagmus upon sitting up, occurred in 76% of persons attributed to pc-BPPV-cu. Upbeat nystagmus with/without torsion and vertigo/retropulsion upon sitting up, occurred in 24% attributed to pc-BPPV-ca short arm. During SHH, canal conversion from pc-BPPV-cu to long arm canalithiasis occurred in 31%. The Half-Hallpike position identified pc-BPPV-cu in 71%. The Inverted Release position identified pc-BPPV-cu adjacent short arm and pc-BPPV-ca short arm.

Persistent, peripheral nystagmus that is downbeat or downbeat/torsion away from involved ear in provoking positions and no nystagmus sitting up, may be attributed to pc-BPPV-cu, and nystagmus that is upbeat or upbeat/torsion towards involved ear upon sitting up may be attributed to pc-BPPV-ca short arm. Both are effectively treated with canal- and mechanism-specific CRPs.

for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: (http://links.lww.com/JNPT/A487).