Anterior Inferior Cerebellar Artery Syndrome Research Articles

A Case of Anterior Inferior Cerebellar Artery Syndrome Accompanied by Polycythemia Presenting Vertigo and Hearing Loss as Initial Symptoms

A Case of Anterior Inferior Cerebellar Artery Syndrome Accompanied by Polycythemia Presenting Vertigo and Hearing Loss as Initial Symptoms

A taxonomy for brainstem cavernous malformations: subtypes of pontine lesions. Part 1: basilar, peritrigeminal, and middle peduncular.

Brainstem cavernous malformations (BSCMs) are complex, difficult to access, and highly variable in size, shape, and position. The authors have proposed a novel taxonomy for pontine cavernous malformations (CMs) based upon clinical presentation (syndromes) and anatomical location (findings on MRI). The proposed taxonomy was applied to a 30-year (1990-2019), 2-surgeon experience. Of 601 patients who underwent microsurgical resection of BSCMs, 551 with appropriate data were classified on the basis of BSCM location: midbrain (151 [27%]), pons (323 [59%]), and medulla (77 [14%]). Pontine lesions were then subtyped on the basis of their predominant surface presentation identified on preoperative MRI. Neurological outcomes were assessed according to the modified Rankin Scale, with a score ≤ 2 defined as favorable. The 323 pontine BSCMs were classified into 6 distinct subtypes: basilar (6 [1.9%]), peritrigeminal (53 [16.4%]), middle peduncular (MP) (100 [31.0%]), inferior peduncular (47 [14.6%]), rhomboid (80 [24.8%]), and supraolivary (37 [11.5%]). Part 1 of this 2-part series describes the taxonomic basis for the first 3 of these 6 subtypes of pontine CM. Basilar lesions are located in the anteromedial pons and associated with contralateral hemiparesis. Peritrigeminal lesions are located in the anterolateral pons and are associated with hemiparesis and sensory changes. Patients with MP lesions presented with mild anterior inferior cerebellar artery syndrome with contralateral hemisensory loss, ipsilateral ataxia, and ipsilateral facial numbness without cranial neuropathies. A single surgical approach and strategy were preferred for each subtype: for basilar lesions, the pterional craniotomy and anterior transpetrous approach was preferred; for peritrigeminal lesions, extended retrosigmoid craniotomy and transcerebellopontine angle approach; and for MP lesions, extended retrosigmoid craniotomy and trans-middle cerebellar peduncle approach. Favorable outcomes were observed in 123 of 143 (86%) patients with follow-up data. There were no significant differences in outcomes between the 3 subtypes or any other subtypes. The neurological symptoms and key localizing signs associated with a hemorrhagic pontine subtype can help to define that subtype clinically. The proposed taxonomy for pontine CMs meaningfully guides surgical strategy and may improve patient outcomes.

Sensorineural Hearing Loss Due to Vertebrobasilar Artery Ischemia-Illustrative Case and Literature Review

Acute sensorineural hearing loss is commonly caused by peripheral vestibulocochlear disorders such as sudden deafness, Meniere’s disease, and Ramsay Hunt syndrome, but is rarely due to infarction of the vertebrobasilar artery. In this report, a case of right anterior inferior cerebellar artery syndrome presenting with sudden deafness and vertigo is described in order to feature acute sensorineural hearing loss due to vertebrobasilar artery ischemia, and sensorineural hearing loss due to vertebrobasilar artery ischemia is reviewed and discussed. A 79-year-old man presented with right acute sensorineural hearing loss preceded by occasional, minute-long periods of dizziness without cranial neural symptoms other than vestibulocochlear symptoms. Magnetic resonance imaging (MRI) revealed infarction of the right anterior inferior cerebellar artery territory. The vertebrobasilar artery supplies the vestibulocochlear organ, brainstem, and cerebellum, whose abnormalities are related to vestibulocochlear symptoms. Vertigo is a major symptom associated with vertebrobasilar artery ischemia. Further, acute sensorineural hearing loss is caused by hypoperfusion of the vertebrobasilar artery. Vertigo and/or acute sensorineural hearing loss could be a prodrome of subsequent infarction of the vertebrobasilar artery territory. The artery most often responsible for acute sensorineural hearing loss is the anterior inferior cerebellar artery, whereas ischemia of the basilar artery, the posterior inferior cerebellar artery, and the superior cerebellar artery rarely cause acute sensorineural hearing loss. Patients with acute sensorineural hearing loss who are at a high risk of cerebrovascular disease must be examined with imaging tools such as MRI.

Anterior inferior cerebellar artery syndrome; without hearing loss

The anterior inferior cerebellar artery (AICA) arises from the lower side of the basilar artery and supplies blood to the rostral olfactory bulb, rostral pontine base, and cerebellar regions. The AICA syndrome was first defined by Adams in 1943. Here, we present a case of a patient with a left AICA occlusion who suddenly started experiencing dizziness and had abnormal gait; he was subsequently diagnosed with ischemia in the left cerebellar hemisphere.A 55-year-old man was admitted to the hospital with complaints of sudden onset of vertigo, speech disorder, and imbalance. The neurological examination revealed gait disturbance, and left-sided ataxia. In addition, dysarthric speech left peripheral facial paralysis, loss of pain and heat sensations in the left half of the face and right half of the body. Bilateral horizontal nystagmus was observed. Babinski and Hoffman signs were also observed on the left side. The patient was evaluated with diffusion weighted (DW) magnetic resonance (MR) imaging. On DW image and apparent diffusion coefficient (ADC) maps precisely determined diffusion restrictions in the antero-inferior part of the left cerebellar hemisphere and the left part of the inferior vermis. MR angiography revealed occlusions in the right internal carotid artery and left AICA; hence, he was administered antiagregan treatment. We have presented this case because infarctions in the AICA have different clinical features from those observed in other cerebellar arteries, and such cases are rarely observed in neurological practice.

AICA syndrome with facial palsy following vertigo and acute sensorineural hearing loss

We report a case of infarction of the anterior inferior cerebellar artery (AICA) with peripheral facial palsy following vertigo and acute sensorineural hearing loss. A 39-year-old female presented with vertigo and sudden hearing loss, tinnitus, and aural fullness of the right ear. An audiogram revealed a severe hearing loss at all tested frequencies in the right ear. Spontaneous nystagmus toward the left side was also observed. Otoneurological examinations showed sensorineural hearing loss of the right ear and horizontal and rotatory gaze nystagmus toward the left side, and a caloric reflex test demonstrated canal paresis. Initially, we diagnosed the patient for sudden deafness with vertigo. However, right peripheral facial palsy appeared 2 days later. An eye tracking test (ETT) and optokinetic pattern test (OKP) showed centralis abnormality. The patient's brain was examined by magnetic resonance imaging (MRI) and magnetic resonance angioglaphy (MRA) and showed an infarction localized in the pons and cerebellum. MRI and MRA revealed infarction of the right cerebellar hemisphere indicating occlusion of the AICA. Consequently, the patient was diagnosed with AICA syndrome but demonstrated regression following steroid and edaravone treatment. We suggest that performing MRI and MRA in the early stage of AICA syndrome is important for distinguishing cerebellar infarction resulting from vestibular disease.

Anterior inferior cerebellar artery syndrome due to vertebral artery dissection following minimal neck injury: a case report

Anterior inferior cerebellar artery syndrome due to vertebral artery dissection following minimal neck injury: a case report

緩徐に神経症状が出現し診断に至った前下小脳動脈症候群例

We report a case of anterior inferior cerebellar artery syndrome (AICA syndrome) in which nervous symptoms gradually appeared. A 69-year-old female with hypertension complaining of vertigo with acute hearing loss and tinnitus of the right ear consulted our hospital. An otoneurological examination demonstrated a sensorineural hearing loss in the right ear and horizontal and rotatory gaze nystagmus toward the left. Initially, we treated her for sudden deafness with vertigo. However, right trigeminal verve paralysis, cerebellar symptoms appeared 3 days later. MRI demonstrated a lesion suggesting anterior inferior cerebellar artery infarction. She was therefore diagnosed to have AICA syndrome. In some cases, other neurological symptoms appear after vertigo and sudden hearing loss. Neurological and MRI examination are important for distinguishing cerebellar infarction from inner ear disease.

前下小脳動脈症候群の３例

Anterior inferior cerebellar artery (AICA) syndrome involves sudden hearing loss, vertigo, and several neurological symptoms and is being reported with increasing frequency due to diagnostic adavances. Herein, we describe 3 cases of anterior inferior cerebellar artery syndrome. Case 1 was a 67-year-old woman with sudden onset of vertigo. Initially, we treated her for sudden deafness with vertigo. Hearing loss improved almost completely by steroid and prostaglandin E1 administration. However, MRI demonstrated cerebellopontine infarction. Case 2 was a 53-year-old woman with hypertension and hyperlipidemia. She had dizziness and headache. CT and MRI demonstrated infarction of the cerebellum and brain stem. Hearing loss and dizziness were improved by steroid administration, control of blood pressure, and antithrombus therapy. She did not have cerebellar symptoms. Case 3 was a 58 year-old man with hypertension, who developed vertigo and vomiting. He demonstrated also hearing loss and ataxia. MRI demonstrated infarction of the cerebellum and brain stem, and otoneurological examination supported these findings. Vertigo and ataxia improved considerably. However, hearing loss was not completely improved. Steroid and prostaglandin E1 administration may improve hearing loss of anterior inferior cerebellar artery syndrome.

若年性脳梗塞に併発した前下小脳動脈症候群

Anterior inferior cerebellar artery (AICA) syndrome has been reported in elder followed by cerebral infarction, however, it is rarely found in young adult. In this study, we reported a case of AICA syndrome associated with nephrotic syndrome in a 19-year-old male. The patient suffered. with left hemiparesis, agnosia, loss of activity, anasarca and left hypacusis after diarrhea and appetite loss, and was diagnosed cerebral infarction in the territory of the anterior choroidal artery by MRI. The symptoms were improved once after medical treatment, however, vertigo and left hearing loss evoked on the 20th day after the first attack. Right horizontal beating nystagmus, no response of left ABR, and ataxia of eye tracking test in ENG were revealed. Although the territory of the AICA had no evidence of ischemic finding in MRI, MR-angiography showed an occlusion of the AICA. Neurotological examination was significantly useful for diagnose in this case.

急性感音難聴で発症した脳幹梗塞の１例

A patient with acute hearing loss and vertigo due to infarction involving the anterior--inferior cerebellar artery (AICA) is reported.A 64-year-old female complained of sudden-onset, severe, unilateral hearing loss and vertigo without any other neurological deficits. Neuro-otological examinations revealed a horizontal, spontaneous, positional, and gaze nystagmus toward the right. Pursuit eye movement and optokinetic nystagmus were unilaterally impaired and ABR showed the absence of waves II-IV and prolonged I-V interpeak latency difference. Based on finding of neuro-otological examination, brain stem lesion was suspected and neuroradiological examinations were performed. MRI showed a pontine infarction in the AICA area and angiography demonstrated stenosis of the right AICA thus the patient was diagnosed as having AICA syndrome.The clinical signs of AICA syndrome are occasionally similar to those of inner ear disorders. In such cases, neuro-otological examinations such as ENG and ABR are clinically useful in distinguishing AICA syndrome from inner ear diseases.

Anterior Inferior Cerebellar Artery Territory Infarcts

Arterial lesions, mechanisms, territory, and clinical features of anterior inferior cerebellar artery (AICA) territory infarcts are only based on necropsy cases. To our knowledge, no large clinical series has been reported. We selected nine consecutive patients with AICA territory infarction confirmed by magnetic resonance imaging and angiography. Atherosclerosis was the only cause and all patients were hypertensive. Patients with pure AICA territory infarcts (n = 4) were diabetic and likely had basilar branch occlusion due to basilar artery plaques that extended into the AICA or microatheroma that blocked the AICA origin. These patients had no or had only recently had (1 day) prodromata. Patients with AICA plus infarct (n = 5) had basilar artery occlusion at the AICA and reconstitution of the distal basilar artery by collaterals through hemispheric anastomoses from the posterior inferior cerebellar arteries and posterior communicating arteries. All these patients except one had prodromata. In seven of nine patients, cranial nerve involvement indicated a lateral pontine lesion in the territory supplied by the AICA. Only two patients had the complete AICA syndrome, and none of the patients had isolated vertigo. The outcome was good in seven of nine patients. Isolated unilateral AICA infarcts should be regarded as most likely due to small artery atherosclerotic disease in diabetic patients. More widespread infarctions that include that AICA territory are due to basilar artery occlusive disease.

環軸関節脱臼を伴った中枢性めまいの２症例

Two patients with anterior inferior cerebellar artery syndrome and cerebellar infarction due to compression of the vertebral artery, caused by atlantoaxial dislocation were treated successfully.Case 1 : a 56-year-old male began having vertigo with sudden sensorineural hearing loss. Case 2 : a 28-year-old female had Meniere's disease-like symptoms. Both patients were treated surgically with reposition and fixation of the atlantoaxial joint. Compression of the vertebral artery was confirmed at surgery. No attacks of vertigo have occurred since surgery.

顔面麻ひが後発した前下小脳動脈症候群

A 67-year-old female was admitted for treatment of vertigo and bilateral hearing loss. Although ATP and vitamin were administered immediately, left upper facial nerve paralysis appeared three days later. CT and MRI revealed old cerebral infarctions without any abnormality in the brain stem or cerebellum. Left anterior inferior cerebellar artery syndrome was detected by vertebral angiography (VAG) with defects in the left anterior inferior cerebellar artery (AICA) and left posterior inferior cerebellar artery (PICA).The observations of spontaneous nystagmus were important for the diagnosis in this case. Early diagnosis is necessary for the prevention of progressive pathology.

椎骨脳底動脈不全に伴う前下小脳動脈症候群

Two patients complaining of hearing loss with vertigo were examined radiologically and neurotologically. Electronystagmography and positional nystagmus testing showed central disturbances. Vertebral angiography (VAG) showed narrowings in the vertebral artery (VA) concomitant with defects in the anterior inferior cerebellar artery (AICA) diagonally opposite to the respective impaired VA branch. We demonstrate in this study that the AICA syndrome resulted from vertebral basilar insufficiency (VBI).Today, due to improvements in CT, MRI and angiography, the AICA syndrome is much better understood. Since VBI will futher complicate AICA syndromes and other secondary disturbances, we conclude that VAG should be performed with care certain cases of vertigo thought to be caused by VBI.

前下小脳動脈症候群と内耳動脈症候群（仮称）

Four patients with anterior inferior cerebellar artery (AICA) syndrome were studied radiologically and neurotologically. Saccadic pursuit in the eye tracking test (ETT) showed dysmetria in two patients, smooth pursuit of ETT showed saccadic patterns in three, and the optokinetic pattern test showed central-type disturbances in three. In all four angiography showed defects of AICA on the diseased side. Two patients had central nystagmus and internal auditory disturbances without cerebellar symptoms. The disorder in these two patients should be called “internal auditory artery (IAA) syndrome” to differentiate it from AICA syndrome.Although AICA syndrome was recognized during the 1930's, it was rarely reported until the 1970's. During the last twenty years, radiological and neurotological studies have made remarkable advances, and AICA syndrome has been clarified. In our present study, we found that special attention should be given to the diagnosis of hearing loss with vertigo; however, diagnosis of some AICA syndrome cases (especially IAA syndrome) can be complicated by peripheral diseases, and so the examination of nystagmus should be performed carefully.

前下小脳動脈循環障害の臨床的検討

前下小脳動脈循環障害の臨床的検討