Bilateral Vestibular Atelectasis with Tullio’s Phenomenon

Abstract

Vestibular dehiscence or atelectasis is a rarity known to cause vertigo. This pathology poses many challenges especially in diagnosis and treatment simply due to the scarcity of reported cases. The etiologic factors, disease pathophysiology and complications remain unclear. We report a young adult female who presented with unsteadiness for 2 years associated with headache. Tullio’s phenomenon was observed which led to a finding of bilateral vestibular dehiscence involving the medial walls on high resolution computed tomography.

Introduction

Vestibular atelectasis is relatively a new entity in the field of neuro-otology and currently often attributed as an etiologic factor for existing vestibular disorders albeit rare in occurrence. Establishment of this pathology follows a landmark retrospective study of temporal bones by Merchant et al. which firstly, expounded the existence of vestibular dehiscence or atelectasis and secondly, provided the basis for another study by Wenzel to corroborate clinical symptoms with the condition [1, 2].

Recognition of this pathology is important as it debilitates the patient with significant morbidity involving gait and balance. Current literature is lacking especially concerning management options.

The objective of this write-up is to report the occurrence of bilateral vestibular dehiscence in a young patient with a short history of Tullio’s phenomenon and disequilibrium.

Case Presentation

A 34-year-old Asian female of Malay race presented with chief complaint of unsteadiness for 2 years. The first occurrence was associated with nausea and vomiting together with aural fullness upon waking up from sleep. She did not experience any form of dizziness, hearing loss or tinnitus except for unsteadiness. There was no specific duration of an intense episode as it was always described as present without affecting her daily activities. The nausea and aural fullness resolved after a day hence she did not seek any medical attention at that time.

Subsequently, the unsteadiness resolved after a few months. She had 1 year of convalescence during which she even underwent an uneventful pregnancy. Three months post-partum, she began experiencing similar unsteady sensation with absence of aural symptoms save for headaches. The headaches were non-specific in terms of localization or intensity. Prolonged upright position was ascribed as a worsening factor. She did not report having any aura, photophobia or any form of vertiginous spells. Her unsteadiness was described as a bothersome floating sensation and more pronounced as compared to before. She consulted a physician who prescribed her with oral betahistine which did not abate her symptoms. Systemically, she was well with no symptoms suggestive of a cardiac related condition. Nevertheless, despite the predicament she continued her daily activities including driving.

Further history revealed no medical illness, no drug and food allergies. Family history was unremarkable especially regarding ear and balance related disorders. She is a mother of three children and works as a teacher. No habits of smoking or alcohol consumption as well as any other high-risk behaviors divulged.

Clinical examination proved to be helpful in directing our line of thought. Positive finding in general ear, nose and throat examination was a small sclerotic patch on the anterior inferior quadrant of her left tympanic membrane. Both the ears were otherwise normal with intact tympanic membrane. Nasal rigid endoscopy showed hypertrophied inferior turbinates and normal post nasal space. Lymphoid aggregates seen on posterior pharangeal wall. Neck examination was unremarkable. Full cranial examination was normal.

Vestibular and cerebellar assessment provided significant results. No spontaneous or gaze evoked nystagmus seen. Smooth pursuit and saccadic eye movement yielded no nystagmus as well, however head thrust (Halmaygi) test displayed abnormal catch-up saccade to the left side with severe unsteadiness resembling momentary convulsive movement of her head and upper body.

Fistula test was positive bilaterally and subsequent exposure of sudden loud noise displayed the same severe unsteadiness with no nystagmus. This confirmed the presence of Tullio’s phenomenon.

Further cerebellar examination showed positive Romberg test with swaying to both sides with eyes close. She was unable to perform tandem gait and Fukuda test due to unsteadiness.

Tuning fork assessment done showed normal Rinne and Weber’s test and subsequent pure tone audiometry displayed a symmetrical low frequency mild sensorineural hearing loss. Tympanogram was type A bilaterally denoting normal middle ear function.

A contrasted high-resolution computed tomography (HRCT) of temporal bone was done delineating the presence of bilateral vestibular dehiscence involving the medial walls (Figs. 1, 2).

Fig. 1.

Right temporal bone. Arrow pointing at dehiscent vestibule

Fig. 2.

Left temporal bone. Arrow pointing at dehiscent vestibule

She was managed conservatively with vestibular rehabilitation and is currently awaiting further follow-up review.

Discussion

Vestibular pathology remains an elusive field in neuro-otology as the signs and symptoms are often subtle and less overt rendering it difficult to place a straight forward diagnosis or syndrome.

As we have gathered from this case, history remains paramount to postulate on the possible causes for such clinical presentation and more so underscoring the significance of proper history taking coupled by a sound clinical assessment. The awareness of Tullio’s phenomenon and more importantly, the clinical acumen and skills to elicit such a vestibular sign is another salient point to remember.

The retrospective study by Merchant et al. can be described as a pioneering work in establishing this entity called vestibular atelectasis. A total of 213 patients involving 426 temporal bone specimens were studied of which 8 patient’s temporal bones were found to have vestibular dehiscence. Interestingly, 5 out of these 8 patients had clinical history of vertigo giving an occurrence percentage of 63% as opposed to the remaining 205 patients who displayed only an 8% occurence of vertigo. This histopathological study was later supported by another significant study by Wenzel et al. who did a case series of patients with Tullio’s phenomenon and horizontal nystagmus [1, 2].

Shucknect’s study was also well described in Shucknect and Nadol textbook of otology; drawing out a comprehensible layout of the disease as well as discussion on the etiologic factors. The revelation of collapsed vestibular wall may be attributed to a defect in the inherent integrity of the membranous wall, faulty gripping action of the perilymphatic trabeculae and the impaired function of the valve in the utricle which maintains the volume of endolymph. These defects affect the response of the mechanoreceptors in the vestibular system which predisposes to vertigo following pressure induced increased firing of receptors. This can be caused by positional head movement or loud sound [3].

The disease is further divided into a primary and secondary entity whereby the former is related to focal infection and degeneration and the clinical course is described to be sudden. Secondary vestibular atelectasis is associated with known vestibular pathologies such as Meniere’s disease, temporal bone fracture and previous otologic surgeries [3].

In the span of 30 years since Merchant et al. published their findings, very few cases were reported regarding vestibular atelectasis and associated conditions and this can only be a reflection of poor diagnostic rate which directly affects the management.

Tullio’s phenomenon or positive Hennerbert sign has been classical in considering the differentials of superior canal dehiscence syndrome and perilympathic fistulas [4]. The latter proves to be another daunting entity as the causes can include Meniere’s, recurrent ear infections, cholesteatoma, syphilis, surgeries especially stapes surgery for otosclerosis or even head trauma. Perilymphatic fistula is described as a communication between the inner perilymphatic space and middle ear or mastoid whereby the alteration of perilymph fluid in the inner ear occurs following triggering factors such as sudden movements and loud sounds. This condition may induce acute vestibular symptoms such as vertigo, episodic hearing loss and tinnitus [5].

Superior semicircular canal dehiscence as mentioned proves less difficult to diagnose as it is relatively more common and easily detectable in high resolution CT of the temporal bone. Besides this, the abundance of available literature on this pathology makes it a well-recognized differential to exclude [6].

The presentation from this case study shows a dearth of important symptoms such as hearing loss, vertigo and significant tinnitus. Absence of antecedent history towards perilymphatic fistulas such as trauma, diving history, or high-risk behaviours suggesting syphilis is also crucial in narrowing down the differential diagnosis. Her initial description certainly weighs towards positional vertigo, most likely benign positional vertigo which holds true as the sudden onset accompanied by nausea and vomiting and later achieving full resolution. Nonetheless, the later presenting symptoms of unsteadiness, dizziness and headaches warrants a new perspective.

This patient has also been having headaches alongside the disequilibrium albeit not always. Migraine related vertigo or vestibular migraine has been extensively studied due to its elusive symptoms and the closely presenting symptoms of Meniere’s disease. Neuhause et al. has established a few parameters to differentiate these two entities which mainly takes into the consideration of the duration of symptoms, associated headaches, migrainous symptoms such as photophobia, aura and the exclusion of other causes by appropriate investigations [7].

The diagnosis of Meniere’s disease was denounced despite her having suffered aural fullness and mild sensorineural hearing loss at lower frequency as the duration of the state of unsteadiness and occasional dizziness extended into months. In addition, a lack of response to betahistine also makes endolympatic hydrops less likely. This leaves us to surmise on vestibular migraine as a possible condition associated with the radiological findings of vestibular atelectasis.

Arriving to a diagnosis aided by history, sound clinical assessment with audiology and imaging merely suggests a causality. A larger vacuum in understanding the disease progression and treatment still exist. Perhaps this pitfall can be greatly improved with more case reports to establish a pattern of the disease onset, progression and inter-relation with other pathology.

Conclusion

In conclusion, the scarcity of knowledge in vestibular atelectasis is still stark requiring more in-depth research and studies to provide definitive management options which are still greatly lacking. By the same token, by analyzing more cases, we may be able to even formulate a diagnostic criteria to improve detection.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Informed Consent

Patient consented for publication.