Diagnosis and Management of Trauma Induced Unilateral Horizontal Canal BPPV with Apogeotropic Nystagmus in an Adolescent

Abstract

This study reported a distinctive case of an adolescent diagnosed with trauma induced BPPV posed by coexisting geotropic and apogeotropic nystagmus. The discussion highlights the pathophysiology and need for repeated vestibular rehabilitation sessions of repositioning manoeuvres for complete resolution of the vertigo.

Introduction

Benign Paroxysmal Positional Vertigo (BPPV) is a common vestibular disorder causing sudden, brief vertigo upon head movement [1]. Geotropic posterior canal BPPV is most common (80%), often associated with aging or head trauma, which intensifies the condition. Research on BPPV predominantly focuses on adults, with limited exploration in the pediatric population where its prevalence is rare (0.4% to 8%) [1]. Pathophysiologically, BPPV occurs when the free otoconia particles, suspended in the endolymph of the otoliths become dislodged, eventually get stuck to the posterior or non-ampullary arm of the semicircular canal (canalithiasis). This leads to geotropic nystagmus (beating towards the ground). Occasionally, particles stick to the cupula of the SSC (cupulolithiasis) which results in apogeotropic nystagmus (beating away from the ground) [2].

Over the years, research studies on BPPV have predominantly concentrated on adults, encompassing aspects of both diagnosis and management, [2] with limited discussion among paediatric or adolescent populations [3]. Therefore, understanding the pathophysiology of the condition among these individuals remains crucial such that the effective management strategies can be implemented. Further, the treatment outcomes for BPPV are contingent upon the subtype and unique patient characteristics. Canalith repositioning maneuvers (CRMs) have exhibited notable efficacy in the management of BPPV, with a success rate of 91% for posterior canal (PC) BPPV cases and 88% for horizontal canal (HC) BPPV cases [2]. Nonetheless, some individuals may endure residual symptoms related dizziness following maneuver, suggesting a multifaceted underlying cause beyond canalolithiasis. Therefore, the present study seeks to present a unique case of apogeotropic horizontal canal BPPV in an adolescent post concussive event (Table 1).

Table 1.

Stimulus parameter and acquisition parameter for tone burst evoked cVEMP, and oVEMP responses

Stimulus parameters
Parameter	cVEMPs	oVEMPs
Frequency	500 Hz, 1000 Hz and 2000 Hz	500 Hz, 1000 Hz and 2000 Hz
Presentation level	95 dB nHL	95 dB nHL
Polarity	Rarefaction	Rarefaction
Repetition rate	5.1/s	5.1/s
Number of sweeps	200	200
Transducer	ER-3A insert phone	ER-3A insert phone
Recording Parameters
Filter setting	10–1000 Hz, 6 dB/octave roll off rate	1–1000 Hz, 6 dB/octave roll off rate
Number of channels	Single	Single
Analysis time	80 ms	80 ms
Recording mode	Ipsilateral mode	Contralateral mode
Artifact rejection	± 400 µV	± 100 µV

Case Presentation

A 13-year-old adolescent came at the outpatient department complaining of persistent vertigo following a trip to amusement park where she took a drop tower ride. Vertigo symptoms began a week after this event, accompanied by complaints of blurry vision and headache. The reported vertigo manifested as a constant sensation of falling backward. Further inquiry revealed that the general physician had prescribed betahistine (16 mg) to alleviate vertigo, but the patient reported minimal improvement. Subsequently, the vertigo became so debilitating that the patient was unable to attend school due to a constant fear of falling backward. Initial examinations, including an MRI, showed no significant findings. Upon additional investigation, it was disclosed that the child had a prior diagnosis of hypothyroidism (attributed to obesity) and was undergoing treatment with Thyroxine (50 mg/day).

During audiological evaluation, the pure tone audiometry revealed bilateral hearing sensitivity within normal limits. Immittance audiometry revealed no middle ear pathology. Starting with VEMPs for the vestibular evaluation, cVEMP showed normal amplitudes and latencies in the right ear, however a shift in tuning was observed towards 1000 Hz in the left ear. As for oVEMP, the right ear has normal amplitudes whereas amplitudes were reduced for the left ear along with having no response for 2000 Hz. Thus, both cVEMP and oVEMP demonstrated impairment in the left ear, while the right ear remained unaffected. (as shown in Fig. 1).

Fig.1.

Illustration of the cVEMP responses. (A.—Right ear; B.—Left ear) and oVEMP (C.—Right ear; D.—Left ear) responses for 500 Hz, 1000 Hz and 2000 Hz tone burst stimulation in the patient

Following this, the video head impulse test (vHIT) was performed using the EyeSeeCam instrument by Interacoustics for all six semicircular canals. The results indicated no abnormalities in the canals or their associated vestibular nerve branches as given in Fig. 2.

Fig. 2.

Illustration of the video head impulse test for all the six semicircular canals in the patient with BPPV

The videonystagmography (VNG) test was conducted using the BalanceEye system (Cyclops Meditech, Bangalore, India). Results for all subsets (saccade test, smooth pursuit test, optokinetic test, gaze test) were within normative ranges.

All positional tests that included Dix-Hallpike test for the posterior canals, the McClure-Pagnini test for the horizontal canals, and the Supine Head-Hanging test for the anterior canals were done using Frenzel goggles to precisely observe eye movements during the tests. The tests were performed in a without-fixation condition (with visual information cutoff using a goggle cover). The Dix-Hallpike test unexpectedly showed left horizontal beating nystagmus instead of anticipated torsional nystagmus. As standard practice, the McClure-Pagnini test was conducted which revealed no nystagmus lying down but upon turning to the right side, an apogeotropic horizontal nystagmus (left beating) was observed, diminishing upon return to the centre and slightly intensifying again to become a geotropic horizontal nystagmus (left beating) on the left side. This confirmed the diagnosis of BPPV of only the right lateral canal for the patient.

Given the visualization of apogeotropic nystagmus, the modified Gufoni Maneuver for apogeotropic nystagmus, a repositioning maneuver, was given. This maneuver aimed to convert the apogeotropic nystagmus into a geotropic nystagmus. Subsequently, the liberatory Gufoni Maneuver was employed to resolve the geotropic nystagmus after a brief interval of 15–20 min. The patient immediately reported a significant reduction in dizziness and rated her problem at 4/10, following the maneuver. Additionally, a set of vestibular rehabilitation exercises were prescribed to enhance the patient's confidence.

When the patient arrived a week later for her next follow up session on 3rd August 2023, she reported some dizziness to still be persisting. Accordingly, the Gufoni maneuver for the geotropic nystagmus was repeated once again as a repetition of the treatment as many times as necessary can be needed in many cases. This session resulted in completely resolved vertigo as rated at 0/10 by the patient. Nonetheless, a follow up was needed to check for any recurrence. Follow-up calls were made on 2 occasions. First after 2 days and the next, a week after the last session. On both follow up calls, the patient reported no recurrence of any vertigo.

The definitive diagnosis of BPPV was established through the various positioning tests performed with the use of frenzel googles which confirmed the presence of a BPPV involving the lateral canal, which was apogeotropic in nature. Though nystagmus during an episode of BPPV are reported to get visualized by the naked eye in most cases, the use of frenzel glasses with vision-denied are found to give a more reliable assessment [3].

In the study, as the Dix-Hallpike test performed during VNG showed horizontal nystagmus instead of torsional nystagmus, nothing could be attributed to the type of BPPV yet. However, on the first visit, upon McClure-Pagnini test, when an apogeotropic nystagmus was seen on position two (turn to right) of the procedure, the diagnosis of cupulolithiasis came into the picture. Moreover, in children the most accepted hypothesis is of cupulolithiasis [1]. This is supported by the study by Baloh et al.[3], who hypothesized that the otoconia is more firmly attached to the macula in children and does not get dislocated. Interestingly, the presence of geotropic nystagmus, when coming to position four (turn to left) of the procedure, was perplexing. However, Nuti et al. [4] described a transient variant of apogeotropic nystagmus which occurs due to the particles settling not in the cupula, but in the anterior or the ampullary arm of the canal. This is also sometimes referred to as the short arm BPPV [2] or apogeotropic canalithiasis[5]. A similar phenomenon was described by Vannucchi et al. [6] when they were treating a patient with apogeotropic BPPV. The transition from apogeotropic to a geotropic nystagmus instead of happening simultaneously in both sides, occurred gradually and they could notice apogeotropic and geotropic nystagmus in the left and the right sides respectively. Such a case has been called direction-fixed paroxysmal nystagmus lateral canal BPPV [7] where the nystagmus is beating to a single direction on both sides of head turns. They also agreed with the explanation given by Vannucchi et al.[6] as such a transition from apogeotropic nystagmus to the classical geotropic form can only mean that the underlying mechanism in those individuals was canalithiasis and not cupulolithiasis. This then changed the diagnosis for the patient from cupulolithiasis to apogeotropic form of canalithiasis. VEMPs were performed on the same day visit as part of the test battery and were found affected. Some studies suggest a link between affected VEMPs and macular degeneration however, because of limited understanding of the pathophysiology, highlighting its unreliability for lateral canal BPPV diagnosis [8].

Subsequent to the consideration of further procedures for managing benign paroxysmal positional vertigo (BPPV), the patient underwent the modified Gufoni Maneuver tailored for apogeotropic nystagmus to convert it into a geotropic nystagmus. This was followed by the liberatory Gufoni maneuver in an attempt to alleviate the vertigo. In cases of horizontal canal BPPV attributed to canalithiasis, geotropic nystagmus is stronger when the affected ear is positioned downward, whereas in cupulolithiasis, the nystagmus becomes apogeotropic and is more pronounced when the affected ear is facing upward [6]. This information is crucial for determining the affected side and the appropriate side for the repositioning maneuver. Notably, a study by Brodsky et al. [1] indicated the successful application of the same repositioning maneuvers in both adult and pediatric populations. The patient responded positively to the intervention, experiencing a swift reduction in vertigo, rated at 4/10. However, consistent with findings by Ahn et al. [9], BPPV resulting from trauma tends to be more intense than its idiopathic counterpart, necessitating a greater number of repositioning maneuver sessions. Consequently, the patient underwent a successive session, receiving the liberatory Gufoni maneuver once again, ultimately leading to a complete resolution of her vertigo.

Abbreviations

BPPV

Benign paroxysmal positional vertigo

SCCs

Semicircular canals

OPD

Outpatient department

MRI

Magnetic Resonance Imaging

VEMPs

Vestibular evoked myogenic potentials

cVEMPs

Cervical VEMPs

oVEMPs

Ocular VEMPs, vHIT: Video head impulse test

VOR

Vestibulo-ocular reflex

VNG

Videonystagmography

Author Contributions

All authors contributed to the study conception, design, material preparation, data collect and analysis and writing the draft of the manuscript. All authors read and approved the final manuscript.

Funding

The authors did not receive support from any organization for the submitted work.

Declarations

Conflict of Interest

The authors have no relevant financial or non-financial interests to disclose.

Consent to participate

Informed consent was obtained from the participant in the study.

Consent to publish

Informed consent was obtained from the participant to the submission of the case report to the journal.

Ethics approval

The study was performed as per the Declaration of Helsinki and authorized by the research advisory committee of the institution.