Cerebellar Cavernous Angioma With Symptomatic Hemorrhage Mimicking Different Sequential Peripheral Vestibular Disorders

Dear Editor,

The etiology of vestibular disorders is broadly categorized into peripheral and central causes. Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular pathology, followed by acute unilateral vestibulopathy (AUVP).1 In contrast, the most common cause of severe central vestibular dysfunction is posterior fossa stroke.1 The symptoms and signs of peripheral and central vestibular dysfunction might overlap, which makes their differential diagnosis challenging even when a comprehensive physical examination is performed with an appropriate instrumental assessment.2, 3, 4 We recently observed a unique case of sequential hemorrhages of a cerebellar cavernoma mimicking two distinct peripheral vestibulopathies.

A 55-year-old male was referred to our department due to the recent onset of positional vertigo with neither auditory nor neurological symptoms. His symptoms had subsided at the time of the evaluation, and his medical history was unremarkable. Video Frenzel goggles revealed minor left-beating spontaneous nystagmus. No gaze-evoked nystagmus was observed and the upright BPPV protocol was not diagnostic.5 Conversely, the head-shaking test (HST) evoked left-beating nystagmus with right head tilt. The seated-to-supine positioning test revealed slight persistent upbeating nystagmus with leftward torsional components. Conversely, the supine head roll test (SHRT) elicited persistent horizontal apogeotropic nystagmus on both sides, with higher amplitude on right positioning and no latency (Supplementary Video 1 in the online-only Data Supplement). Nystagmus was not associated with symptoms.

Assuming the presence of fading left apogeotropic horizontal semicircular canal BPPV (HSC-BPPV), several unsuccessful repositioning maneuvers were attempted. The findings of audiometry and video head impulse test (vHIT) were unremarkable. Brain contrast-enhanced magnetic resonance imaging (MRI) revealed signs of recent bleeding of a small cavernous malformation involving the left inferior cerebellar peduncle (ICP) (Fig. 1A-E). Although nystagmus completely receded within 1 week, the patient was enrolled in a close radiological follow-up.

Fig. 1
Radiological and instrumental assessments of the patient with cerebellar CASH after the first hemorrhage mimicking left apogeotropic HSC-BPPV (A-E) and after the second hemorrhage mimicking left AUVP (F-J). Brain axial T1-weighted MRI showing a small cavernoma (0.6 mm×0.7 mm×0.8 mm) in the left ICP (A). vHIT using an ICS video-oculographic system (GN Otometrics, Ballerup, Denmark) showing VOR gain values within normative ranges for all SCs (B). PTA showed normal thresholds (C). Ocular (D) and cervical (E) VEMPs recorded using a two-channel evoked potential acquisition system (Neuro-Audio, Neurosoft, Ivanovo, Russia) revealed symmetrical amplitudes. Brain axial T1-weighted MRI showing enlarged CASH (15 mm×9 mm×17 mm) with the typical popcorn appearance of the lesion involving the REZ of the left VIII CN (F). vHIT showing VOR-gain impairment for all left SCs with mainly overt saccades (G). Unremarkable PTA findings (H). Ocular (I) and cervical (J) VEMPs revealing absent potentials on the left side and normal responses on the right. AUVP, acute unilateral vestibulopathy; BPPV, benign paroxysmal positional vertigo; CASH, cavernous angioma with symptomatic hemorrhage; CN, cranial nerve; HSC, horizontal semicircular canal; ICP, inferior cerebellar peduncle; MRI, magnetic resonance imaging; PTA, pure-tone audiometry; REZ, root entry zone; SC, semicircular canal; VEMPs, vestibular evoked myogenic potentials; vHIT, video head impulse test; VOR, vestibulo-ocular reflex.

• Click for larger image
• Download as PowerPoint slide

Nine months later, the patient was evaluated again for acute vertigo that had occurred within approximately 24 hours with nausea and vomiting but without auditory symptoms. Spontaneous right-beating horizontal–torsional nystagmus suppressed by visual fixation was observed. The alternate-cover test was negative, and the bedside vHIT revealed refixation saccades after leftward head impulses, consistent with left AUVP. Audiometry was unremarkable. While the HST did not modify the spontaneous nystagmus, severe hypofunction involving all of the left semicircular canals was detected in the vHIT. Air-conducted vestibular evoked myogenic potentials revealed both saccular and utricular impairments on the left side. Repeat brain MRI showed a recent larger hemorrhage from the same cavernoma involving the root entry zone (REZ) of the left VIII cranial nerve (CN) (Fig. 1F-J). Since the patient refused invasive procedures, he was enrolled in wait-and-see management. Seven days later, the spontaneous nystagmus had reduced, consistent with a compensation process. Nevertheless, several discrepancies were recorded, including the contralesional head tilt and the lack of nystagmus augmentation after the HST (Supplementary Video 2 in the online-only Data Supplement). The lesion size was stable in MRI and no additional symptoms were evident at an 18-month follow-up.

Patients with brain cavernous malformations may present with a broad range of symptoms, including seizures (50%), focal neurological deficits without radiographic evidence of recent hemorrhage (25%), and symptomatic hemorrhages (25%).6 Cavernous angioma with symptomatic hemorrhage (CASH) is a paradigm of a common neurovascular lesion with consequential clinical sequelae.7

Positional nystagmus may occur in both central and peripheral vestibular lesions.8, 9 In our case, a cerebellar CASH initially presented with central positional nystagmus (CPN) mimicking apogeotropic HSC-BPPV. Differentiating between CPN and BPPV can be challenging. CPN results from impaired modulation of the vestibular signals by the cerebellar nodulus and uvula. Since afferents running from the nodulus and uvula to the vestibular nuclei are conveyed by the ICP, a lesion in that area may lead to CPN.10 The lack of symptoms and latency of positional nystagmus in the SHRT, the detection of vertical/torsional components during the other positioning maneuvers, and the ineffectiveness of the physical treatment suggested a central vestibular dysfunction in our patient.

After a few months with no symptoms, new bleeding resulted in an enlarged CASH involving the left VIII CN REZ, leading to a clinical picture consistent with left AUVP. Spontaneous nystagmus results from acute dysfunction involving either the peripheral or central vestibular pathways. A lesion in the VIII CN REZ is likely to mimic ipsilesional AUVP due to sudden asymmetry of the vestibular inputs. In similar cases, the HINTS protocol11 and the instrumental tests for vestibular function might not be able to differentiate peripheral from central causes. The utmost attention should be paid to the associated neurological symptoms and the patient’s history.

Despite ever-expanding knowledge in various vestibular fields, the differential diagnosis of acute vertigo remains challenging and can be correctly addressed only by a comprehensive clinical assessment focusing on a constellation of symptoms, vestibular signs, and instrumental tests.