Atypical variants of posterior canal benign paroxysmal positional vertigo after canalith repositioning: a case report

Abstract

Background and purpose: Unsuccessful repositioning of posterior canal benign paroxysmal positional vertigo (PC-BPPV) can result in inadvertent aggregation of otoconia in atypical areas of the PC. A collection of otoconia within the non-ampullary segment of the PC can provoke a downbeating and torsional positional nystagmus creating diagnostic uncertainty. Further complicating the clinical picture, otoconia may concurrently become displaced in areas adjacent to the utricle, such as the utricular side of the PC ampulla. Current evidence regarding the treatment of atypical PC-BPPV is limited, and the ideal treatment method remains in question.

Case description: This case report describes the management of an individual presenting with atypical downbeating and torsional positional nystagmus of PC origin. The simultaneous presence of reversed nystagmus when positioned in supine with the head flexed 30 degrees, further complicated the differential diagnosis.

Intervention: This individual was treated with the demi-semont (DS) maneuver to treat suspected right-sided apogeotropic posterior canal BPPV (APC-BPPV) with concurrent utricular side cupulolithiasis of the posterior canal (UCPC-BPPV).

Outcome and discussion: When reassessed the day after treatment the patient’s positional nystagmus and vertigo were resolved, indicating successful treatment of suspected APC-BPPV with concurrent UCPC-BPPV. The patient, in this case, responded to the DS maneuver, however, the current evidence regarding of semicircular canal fluid mechanics supports minimizing the inertial elements of canalith repositioning maneuvers, while extending the duration of the rest intervals during the repositioning maneuver. In patients that present with positional downbeating nystagmus, without signs of central pathology, we suggest considering APC-BPPV as a potential diagnosis. In addition, we suggest that excitation of the PC in the supine head flexed (SHF) position without similar findings in the DH position may represent aggregation of otoconia on the posterior side the cupula within the PC ampulla.

Keywords:

• Benign paroxysmal positional vertigo
• BPPV
• vestibular
• dizziness

Acknowledgements

Dr. Julie Honaker for advice and guidance pertaining to the subject matter covered within the case report.

Disclosure statement

No potential conflict of interest was reported by the author.