Cerebellar infarct mimicking Meniere’s disease

The acute ischemic stroke in the distribution of anterior inferior cerebellar artery (AICA) is known to be associated with vertigo, nystagmus, hearing loss, facial weakness, ataxia, hypalgesia, and dysarthria. Although the syndrome associated with AICA occlusion was completely described six decades ago, hearing loss in these patients has been poorly investigated.

A case of a 65-year old man with sudden hearing loss and vertigo due to acute cerebellar infarct is presented. The patient presented to our hospital because of vertigo, left sided hearing loss and tinnitus. On admission, he had a gaze-evoked horizontal right directional nystagmus and a positive Romberg test. Pure tone audiometry showed severe sensorineural hearing loss on the left. Stapedial reflex was absent ipsilaterial but was recorded conralateral. Computed tomography of the brain was negative for acute lesion of the cerebellum of the pons. The rest neurological examination was negastive for central nervous system disorder and the patient was admitted to the ENT department with possible diagnosis of Meniere’s disease. Eight hours later, a new neurologic examination revealed gaze-evoked bi-directional horizontal nystagmus, left limb dysmetria and gait ataxia. Magnetic resonance imaging revealed a hyperintense lesion in the left cerebellar peduncle and the patient was transferred to the Neurological department with the diagnosis of acute cerebellar infarct. the neurotologic examination was completed five days later. No transient-evoked otoacoustic emissions were recorded on the left, and or ABR testing no responses were evoked by stimulation on the left side. Videonystagmography showed severe hypoesthesia to caloric stimulation on the left side. Left limb coordination and gait improved steadily over several days. Follow-up pure tone audiometry at 20 days revealed significant improvement of hearing on the left.

The inner ear is particular vulnerable to transient ischemia because of its high-energy requirements and lack of adequate collateral blood supply. Inner ear is supplied by the internal auditory artery (IAA), which usually derives from AICA but sometimes directly from the basilar artery. Thus, clinical presentation of the syndrome associated with AICA occlusion may include sensorineural hearing loss. However, the incidence of hearing loss reported in these patients varies from 30 to 100%. In fact, neurologists have not included audiologic evaluation in routine examination. On the other hand, it is possible, if hearing loss is mild or moderate, patients to be unaware of tit due to their severe symptoms of vertigo and nausea.

Our patient presented with the symptoms of Meniere’s disease. Eight hours later, symptoms indicating lesion of the central nervous system were added to his first clinical presentation. Meniere’s disease is classically characterized by recurrent episodes of rotatory vertigo or dizziness, fluctuating, progressive, low-frequency hearing loss, tinnitus and a sensation of “fullness” or pressure in the ear. Its aetiology is unknown, however, genetic, traumatic, viral, microbial, autoimmune and other factors have been implicated.

In conclusion, because the clinical presentation of AICA infarction may mimic other vestibular disorders such as vestibular neuritis or Meniere’s disease, a detailed neurologic examination is essential focusing on additional brainstem signs such as, crossed sensory loss, lateral gaze palsy or facial palsy. On the other hand, patients with sudden hearing loss without any other pathologic neurologic sign should be under close observation, as sudden sensorineural hearing loss has been reported as a precursor sign of AICA occlusion. It is well recognized that tinnitus is a very common complaint, even in individuals with normal hearing, and is not usually taken as a warning sign of an impending stroke. Finally, audiologic evaluation and complete neurotologic examination are advised in all patients with acute cerebellar infarcts, as this will reveal the real incidence of co-existing hearing impairment.

Key words: Sudden hearing loss, Meniere’s disease, cerebellum infract.