Persistent Direction-Fixed Nystagmus Following Canalith Repositioning Maneuver for Horizontal Canal BPPV: A Case of Canalith Jam

Abstract

The authors report a 64-year-old man who developed persistent direction fixed nystagmus after a canalith repositioning maneuver for horizontal canal benign paroxysmal positional vertigo (HC-BPPV). The patient was initially diagnosed with right HC-BPPV given that the Dix-Hallpike test showed geotropic horizontal nystagmus that was more pronounced on the right side, although the roll test did not show any positional nystagmus. The patient was treated with a canalith repositioning maneuver (Lempert maneuver). The next day, the patient experienced a different character of dizziness, and left-beating spontaneous nystagmus regardless of head position was observed. After a forced prolonged left decubitus and frequent head shaking, his symptoms and nystagmus resolved. This condition, referred to as canalith jam, can be a complication after the repositioning maneuver in patients with BPPV. Atypical positional tests suggest that abnormal canal anatomy could be the underlying cause of canalith jam.

Feasibility of Using the Video-Head Impulse Test to Detect the Involved Canal in Benign Paroxysmal Positional Vertigo Presenting With Positional Downbeat Nystagmus

“…As already described for HSC-canalith jam ( 87 , 88 ), this mechanism may prevent both high- and low-frequency responses for the SC affected (namely head impulses and otoconial shifts, respectively) by blocking endolymphatic flows, likewise surgical plugging ( 89 ), thus explaining severe impairment of canal VOR-gain. Though canalith jam has been described for HSC in several reports, occurring either spontaneously ( 87 , 88 , 90 , 91 ) or as a result of inappropriate CRP ( 92 – 94 ), a similar condition involving PSC has been recently implied as the hypothetical pathomechanism for spontaneous DBN receding after proper physical treatment ( 95 ). Whereas, spontaneous nystagmus resulting from HSC-canalith jam overlaps presenting signs of acute vestibular loss, spontaneous VOG findings due to a PSC involvement should be mainly torsional/vertical aligning with vertical SC axis, thus mimicking CNS pathologies.…”

The long-term follow-up of 61 horizontal canal BPPV after Gufoni and Barbecue maneuver: a prospective study

“…There are no other side effects except dizziness and symptoms of the vegetative nervous system. Persistent nystagmus has occasionally been reported after restoration, but it can be rapidly alleviated [7]. Brandt-Daroff exercise method and repeated CRM are recommended for the cases of CRM failure; while drug therapy is only auxiliary [8] and they all have no impact on the recurrence rate [9].…”

Recovery Phase Spontaneous Nystagmus, Its Existence and Clinical Implication

“…There are some cases that lesion side determined by vestibular function tests is not identical between the tests at different time points. Besides the central nystagmus [2-4] and atypical benign paroxysmal positional vertigo [5,6], most probable explanation for this is recovery spontaneous nystagmus (rSN). rSN usually follows the initial paralytic nystagmus [7].…”