Inferior Cerebellar Artery Territory Infarction Research Articles

Spontaneous vertebral artery stenosis, dissection and cerebellar infarction in a gentleman while playing bowling.

Background: An increased incidence of vertebral artery dissection has recently become a recognized cause of acute stroke for about 1/5 of strokes in young patients. Case Presentation: A male in his 30s presented to the emergency department with sudden onset of severe vertigo, vomiting, and dizziness while he was playing bowling. The symptoms started when he suddenly twisted his neck while throwing the ball towards pins. Initial diagnosis of central vertigo led to performing plain CT head and CT head angiogram, which demonstrated non-occlusive extradural left vertebral artery dissection. Following CT scans, an MRI head, and MRA head and neck were performed which confirmed the CT diagnosis and also showed left posterior inferior cerebellar artery territory infarcts with micro haemorrhages. The patient was started on dual antiplatelet medications which was continued for 6 months with a follow up MRI/MRA scan of head and neck. Conclusion: This appears to be a unique case where sudden twisting of the neck possibly resulted in vertebral artery dissection and cerebellar infarction. Hence, it is vital to be aware of sports related presentation resulting in sudden neck movements and tear in vertebral artery causing dissection.

English

Suicide is the eighth leading cause of death in males, while strangulation injuries account for approximately 2.5% of all traumatic deaths worldwide. Hanging or ‘self-suspension’ is a form of ligature strangulation where the pressure is produced by the weight of the body itself. It is easily accessible, comparatively painless, almost always suicidal and cheap method of committing suicide. These attributes make it one of the most common methods of committing suicide all over the world. We report a case of isolated posterior inferior cerebellar artery stroke secondary to hanging, (which is a very rare entity) in a 15 years old boy brought in an unconscious state following a suicide attempt to the emergency in GTBH, Delhi. He presented there with a Glasgow Coma Scale score of 6/15 ,ligature mark over the neck, normal vital signs with low oxygen saturation by pulse oximeter, cyanosis, subconjunctival hemorrhage and positive bilateral Babinski sign. The patient was intubated and put on ventilator support in view of respiratory failure. Patient’s magnetic resonance imaging (MRI) brain was done which showed left posterior inferior cerebellar artery territory infarct with cytotoxic edema in bilateral thalami, most likely due to hypoxia. After vigorous treatment in the intensive care unit with fluid restriction, mannitol and intravenous antibiotics he was extubated and transferred to the general ward with glasgow coma scale score of 8/15 (E4V1M3). Later patient was discharged from the hospital and with an advice to follow up in medical and pshychiatry outpatient departments. Survival and recovery after partial hanging is possible if proper care is given as early as possible. We also need to understand the changes which adolescents face in their day to day life and hence be more alert to any social, emotional or professional stress in their life. Also, we should provide counseling and necessary support so that such accidents are deterred. Key words: Near-hanging, posterior inferior cerebellar artery stroke.

Abstract T P177: Non-dominant Vertebral Artery With Higher Resistance Flow Pattern Is A Risk Factor For Ischemic Stroke

Background and aims: The diameters of the vertebral arteries (VAs) are very often unequal and the larger artery is called ‘dominant’. We investigated whether the hemodynamic parameters differ between the ‘dominant’ and ‘non-dominant’ variants. Methods: Consecutive patients who underwent computed tomographic angiography (CTA) of cervical and intracranial arteries, cervical duplex (CDU) and transcranial Doppler (TCD) ultrasonography were included. VA diameters (cervical and intracranial segments) were measured on CTA. Flow velocities recorded were peak systolic (PSV), end-diastolic (EDV), mean flow (MFV). Pulsatility index (PI) and ratio of distal-to-proximal VAs were computed. Results: Of the total 501 patients admitted during 2012 with acute ischemic stroke, both CTA and ultrasound data were available for VAs for 161 (32%). The dominant VA was more frequent on the left side (p<0.01). Non-dominant VAs were found to have lower MFV (27cm/s versus 38cm/s; p<0.01) and higher PI (1.27 versus 1.0; p<0.01) as compared to the dominant variant. In most patients, proximal basilar artery was noted to be on the side of non-dominant artery. Posterior inferior cerebellar artery territory infarcts and lateral medullary infarcts were noted in 38 (7.6%) patients. These infarcts were noted more commonly on the same side as the non-dominant intracranial VA side (p<0.01), especially when associated with low MFV (p<0.01) and high PI (p<0.01). Conclusions: The risk of ischemic stroke in VA territory is higher with the non-dominant artery, especially when it is associated with higher-resistance flow pattern.

Vertigo Due to Posterior Circulation Stroke

Stroke in the distribution of the posterior circulation may present as acute onset spontaneous vertigo and imbalance. Although vertigo due to posterior circulation stroke is usually associated with other neurologic symptoms or signs, small infarcts in the cerebellum or brainstem can present with vertigo without other localizing symptoms. Approximately 17% of patients with isolated posterior inferior cerebellar artery territory infarction presented with isolated vertigo, nystagmus, and postural unsteadiness. A head impulse test can differentiate acute isolated vertigo associated with cerebellar stroke from more benign disorders involving the inner ear. Sometimes acute isolated audiovestibular loss can be the initial symptom of impending posterior circulation ischemic stroke (particularly within the territory of the anterior inferior cerebellar artery). In this case, evaluation of isolated audiovestibular loss may prevent the progression of acute vertigo and hearing loss into more widespread areas of infarction in the posterior circulation. In this article, the clinical syndromes and signs of acute vestibular syndrome due to posterior circulation stroke involving the brainstem and cerebellum are summarized.

Factors Associated with the Misdiagnosis of Cerebellar Infarction

Cerebellar infarction is easily misdiagnosed or underdiagnosed. In this study, we investigated factors leading to misdiagnosis of cerebellar infarction in patients with acute ischemic stroke. Data on neurological and radiological findings from 114 consecutive patients with acute cerebellar infarction were analyzed. We investigated factors associated with misdiagnosis from the data on clinical findings. Thirty-two (28%) patients were misdiagnosed on admission. Misdiagnosis was significantly more frequent in patients below 60 years of age and in patients with vertebral artery dissection, and significantly less frequent in patients with dysarthria. It tended to be more frequent in patients with the medial branch of posterior inferior cerebellar artery territory infarction, and infrequent in patients with the medial branch of the superior cerebellar artery territory infarction. Thirty out of 32 (94%) misdiagnosed patients were seen by physicians that were not neurologists at the first visit. Twenty-four of 32 (75%) misdiagnosed patients were screened only by brain CT. However, patients were not checked by brain MRI or follow-up CT until their conditions worsened. Patients below 60 years of age and patients with vertebral artery dissection are more likely to have a cerebellar infarction misdiagnosed by physicians other than neurologists.

Profound Gastroparesis after Bilateral Posterior Inferior Cerebellar Artery Territory Infarcts (P01.030)

Objective: To describe a case of acute gastroparesis as a result of medullary infarction. Background Function of the gastrointestinal system is partially dependent upon the integrity of the lower brain stem. While dysphagia commonly results from strokes of varying locations, acute dysfunction of other segments of the alimentary canal from stroke is not a well-described phenomenon. Design/Methods: Case report. Results: A 65 year old man with a history of diabetes mellitus without previous gastrointestinal difficulty presented with sudden onset vertigo, nausea, vomiting, a left Horner9s syndrome and hemiataxia, as well as gait ataxia. Magnetic resonance imaging (MRI) revealed an acute infarction in the midline cerebellum bilaterally and the left posterior caudal medulla, all within the right and left posterior inferior cerebellar artery (PICA) territories. Over the following week, the persistent nausea, vomiting, and vertigo gave way to severe nausea and vomiting exclusively after eating, accompanied by instantaneous satiety. Brain imaging demonstrated acute infarction of the midline cerebellum bilaterally and the left posterior caudal medulla. Serial cranial CT scans revealed minimal changes; a contrast-enhanced abdominal CT and endoscopy showed severe gastric distention but no anatomical obstruction of the gut. A gastric emptying study demonstrated 99% retention of the radiolabled meal on serial scintigraphy after 2, 3, and 4 hours post-ingestion, with minimal activity seen in the duodenum, consistent with severe gastroparesis. His symptoms were refractory to medical management, and he required a jejunostomy tube for 8 weeks as his oral intake gradually improved. Conclusions: Acute, isolated gastroparesis without gastrointestinal pathology can result from medullary infarctions. A possible explanation may be infarction or edema particularly affecting the pars centralis of the nucleus of the tractus solitarius. Preexisting diabetes mellitus may also have been a predisposing factor. Disclosure: Dr. Liff has received personal compensation for activities with E-Rewards Medical. Dr. Labovitz has nothing to disclose. Dr. Robbins has nothing to disclose.

Infarction in the Territory of Anterior Inferior Cerebellar Artery

To define the detailed spectrum of audiovestibular dysfunction in anterior inferior cerebellar artery territory infarction. Over 8.5 years, we prospectively identified 82 consecutive patients with anterior inferior cerebellar artery territory infarction diagnosed by MRI. Each patient completed a standardized audiovestibular questionnaire and underwent a neuro-otologic evaluation, including bithermal caloric tests and pure tone audiogram. All but 2 (80 of 82 [98%]) patients had acute prolonged vertigo and vestibular dysfunction of peripheral, central, or combined origin. The most common pattern of audiovestibular dysfunction was the combined loss of auditory and vestibular function (n=49 [60%]). A selective loss of vestibular (n=4 [5%]) or cochlear (n=3 [4%]) function was rarely observed. We could classify anterior inferior cerebellar artery territory infarction into 7 subgroups according to the patterns of neuro-otological presentations: (1) acute prolonged vertigo with audiovestibular loss (n=35); (2) acute prolonged vertigo with audiovestibular loss preceded by an episode(s) of transient vertigo/auditory disturbance within 1 month before the infarction (n=13); (3) acute prolonged vertigo and isolated auditory loss without vestibular loss (n=3); (4) acute prolonged vertigo and isolated vestibular loss without auditory loss (n=4); (5) acute prolonged vertigo but without documented audiovestibular loss (n=24); (6) acute prolonged vertigo and isolated audiovestibular loss without any other neurological symptoms/signs (n=1); and (7) nonvestibular symptoms with normal audiovestibular function (n=2). Infarction in the anterior inferior cerebellar artery territory can present with a broad spectrum of audiovestibular dysfunctions. Unlike a viral cause, labyrinthine dysfunction of a vascular cause usually leads to combined loss of both auditory and vestibular functions.

Neuropsychological disturbances in cerebellar infarcts.

Recent clinical and research reports suggest that the cerebellum may contribute to the modulation of higher cognitive functions. We included 15 consecutive patients with isolated cerebellar infarcts (4 superior cerebellar artery territory infarcts, 1 anterior inferior cerebellar artery territory infarct and 10 posterior inferior cerebellar artery territory infarcts), all confirmed by magnetic resonance imaging. These subjects plus 15 controls matched for age, sex, and educational level underwent a neuropsychological test battery including vocabulary, similarities and block design subtests of the Wechsler Adult Intelligence Scale Revised (WAIS-R); verbal fluency tests (categorial, phonemic, and alternate categorial fluency tests); Rey's 15 auditory word learning list; the paced auditory serial addition task; the Stroop test and the Zerssen Rating Scale. One year after the cerebellar infarct, each subject with cerebellar infarct was asked to undergo a second neuropsychological examination with the same test battery. Patients with cerebellar infarcts exhibited significantly lower neuropsychological performances compared to those of the control group without any obvious difference between the different vascular cerebellar territories. After 1 year of follow-up, this neuropsychological impairment tended to improve. The pattern of deficits observed in isolated cerebellar infarcts highlights the nonmotor functions of the cerebellum and functional relationship between the cerebral cortex and the cerebellum.

Ocular tilt reaction due to unilateral cerebellar lesion

We report two patients with an ocular tilt reaction (OTR) due to unilateral caudal cerebellar lesion. One patient had a caudal cerebellar hemorrhage, the other a posterior inferior cerebellar artery territory infarct. There was head tilt in both patients which had not been reported previously. These findings support the previous proposal that the mechanism of a tonic contraversive OTR with unilateral cerebellar lesion is an increased tonic resting activity in the ipsilesional vestibular nucleus due to a loss of inhibition from the lesioned nodulus.

When is Isolated Vertigo a Harbinger of Stroke?

Isolated vertigo is usually a distressing though benign clinical entity. Recently, however, it has been recognized that in a subset of patients isolated vertigo may be a harbinger of vertebrobasilar stroke. Recognition of this "at risk" subgroup may be difficult. Brainstem auditory evoked potentials (BAEPs) are usually normal in patients with vertigo from labyrinthine disease. We describe a patient with isolated vertigo, in whom BAEPs were abnormal, and who subsequently developed an anterior inferior cerebellar artery territory infarct. BAEP testing might lead to early recognition of those patients at risk for catastrophic stroke, and prompt appropriate investigation and treatment to prevent this outcome.

Cerebellar infarction. Clinical and anatomic observations in 66 cases.

Cerebellar infarction displays different clinical features, depending on the vascular territory involved. We studied patients with infarcts in the territories of the posterior inferior cerebellar artery or the superior cerebellar artery to compare their clinical presentation, course, and prognosis. We retrospectively analyzed the clinical features, laboratory data, and imaging studies of 66 patients with cerebellar infarction collected consecutively at five institutions. All the cerebellar infarcts were documented on computed tomographic scan or magnetic resonance imaging. Two distinct profiles emerged, depending on the vascular territory involved. In 36 patients with posterior inferior cerebellar artery territory infarcts, a triad of vertigo, headache, and gait imbalance predominated at stroke onset. Computed tomography showed severe cerebellar mass effect in 11 cases (30%), with associated hydrocephalus in seven. In these seven patients (19%), postinfarct swelling led to brain stem compression that resulted in four deaths. In 30 patients with superior cerebellar artery infarcts, gait disturbance predominated at onset; vertigo and headache were significantly less common. The clinical course was usually benign. Computed tomography showed marked cerebellar mass effect, hydrocephalus, and brain stem compression in only two instances (7%). Presumed cerebral embolism was the predominant stroke mechanism in patients with superior cerebellar artery distribution infarcts, whereas in those with posterior inferior cerebellar artery distribution infarcts, the stroke mechanism was equally divided between cardiogenic embolism and posterior circulation arterial disease. Cerebellar infarcts in the posterior inferior cerebellar artery and superior cerebellar artery distribution have distinct differences in clinical presentation, course, and prognosis. These differences should help in the selection of appropriate monitoring and treatment strategies.