Acute bilateral cerebellar infarction in the territory of the medial branches of posterior inferior cerebellar arteries

Baseline Factors Affecting the Prognosis of Ischemic Cerebellar Stroke Patients in Turkey: A Cross-Sectional Study

BACKGROUND

Cerebellar infarcts are encountered commonly in clinical practice; however, they are likely to be misinterpreted. They cannot be adequately evaluated on scales such as the National Institute of Health Stroke Scale (NIHSS), which can have fatal consequences.

AIM

To evaluate the baseline features, prognosis, and 6-month survival in patients with cerebellar stroke.

METHODS

A total of 200 patients with cerebellar ischemia were included in the study. Patients were analyzed retrospectively from 10 years of data. Both univariate and multivariate analyses were evaluated.

RESULTS

Mean age was 68 years old, and men were more frequently affected. The most common symptoms were dysarthria and vertiginous sensations. Ischemic lesions were usually cortical/juxtacortical, multiple, hemispheric, and small (below 1.5 cm). The most commonly affected artery was the medial branch of the posterior inferior cerebellar artery. Cardioembolism was the more frequent etiology. Gait ataxia was associated with a more favorable prognosis and 6-month modified Rankin Scale (mRS) scores (OR: 0.15, 95% CI, P = 0.03). Older age (OR: 1.75, 95%, P = 0.02), female gender (OR: 6.72, 95%, P = 0.02), multiple (OR: 10.92, 95%, P = 0.01) and large lesions (OR: 6.56, 95% CI, P = 0.01), posterior circulation ischemic lesions extra-cerebellum (OR: 8.33, 95% CI, P = 0.01), left ventricular apical hypokinesia or AF (OR: 5.58, 95% CI, P = 0.02), and a high mRS score on admission (OR: 5.21, 95% CI, P < 0.001) was correlated with higher 6-month mRS and a lower survival rates.

CONCLUSION

The study found that some baseline clinical, neurovascular imaging findings, and the mRS score on admission are useful predictors of cerebellar stroke prognosis and outcome.

Subarachnoid Hemorrhage Due to Ruptured Intracranial Aneurysm Arising from a Vertebral Artery-Bihemispheric Posterior Inferior Cerebellar Artery Bifurcation

Although the anatomy of the posterior inferior cerebellar artery (PICA) is highly variable, a solitary PICA supplying both hemispheres of the cerebellum is rare. A 76-year-old woman presented with severe headache and subsequent loss of consciousness and was admitted to our hospital. Initial computed tomography showed subarachnoid hemorrhage. Three-dimensional digital subtraction angiography revealed a saccular aneurysm arising from the right vertebral artery (VA)-PICA bifurcation. The PICA branching from the right VA was enlarged, tortuous, and crossed the midline to supply both cerebellar hemispheres. This right PICA was interpreted as a bihemispheric PICA. Recognizing this variant preoperatively could help prevent complications of surgery. Careful follow-up studies are necessary in cases with bihemispheric PICA to monitor for the development of aneurysm at the junction between the bihemispheric PICA and the VA or the distal portion of the bihemispheric PICA.

Noncommunicating Hydrocephalus

Noncommunicating hydrocephalus is often referred to as obstructive hydrocephalus and is by definition an intraventricular obstruction of cerebrospinal fluid flow. Patient symptoms depend on the rapidity of onset. Acute obstructive hydrocephalus causes sudden rise in the intracranial pressure, which may lead to death, whereas in chronic hydrocephalus there may not be any symptoms. Computed tomography and magnetic resonance imaging play important roles in the diagnosis and management of hydrocephalus. Advances in magnetic resonance imaging such as the 3D sequences and phase-contrast imaging have revolutionized the preoperative and postoperative assessment of noncommunicating hydrocephalus. We would be discussing the various causes of noncommunicating hydrocephalus and their imaging.

Intraoperative visualization of bilateral thrombosis in the posterior inferior cerebellar artery apparent in the telovelomedullary segment

Unilateral posterior inferior cerebellar artery (PICA) thrombosis is frequent. However, bilateral PICA thrombosis is rare. Herein we report about an intraoperative visualization of a bilateral thrombosis of the telovelomedullary segment of the PICA. A 74-year-old woman was admitted to our department on day two of a bilateral PICA thrombosis with developing cerebellar infarction. Her Glasgow Coma Scale score dropped from 15 to 13, and cranial computed tomography revealed compression of the fourth ventricle with consecutive occlusive hydrocephalus. After the insertion of an external ventricular drainage, the patient underwent urgent suboccipital decompressive craniectomy with removal of infarcted cerebellar tonsils, which allowed the bilateral visualization of the thrombosed telovelomedullary segments. The surgical access may offer surgical therapeutic options in a hyperacute occlusion, such as thromb-/embolectomy or bypass procedures.

Space-occupying cerebellar infarction: complications, treatment, and outcome

Space-occupying brain edema is a frequent and one of the most dreaded complications in ischemic cerebellar stroke. Because the tight posterior fossa provides little compensating space, any space-occupying lesion can lead to life-threatening complications through brainstem compression or compression of the fourth ventricle and subsequent hydrocephalus, both of which may portend transtentorial/transforaminal herniation. Patients with large cerebellar infarcts should be treated and monitored very early on in an experienced stroke unit or (neuro)intensive care unit. The general treatment of ischemic cerebellar infarction does not differ from that of supratentorial ischemic strokes. Treatment strategies for space-occupying edema include pharmacological antiedema and intracranial pressure–lowering therapies, ventricular drainage by means of an extraventricular drain, and suboccipital decompressive surgery, with or without resection of necrotic tissue. Timely escalation of treatment is crucial and should be guided by clinical and neuroradiological rationales. Patients in a coma after hydrocephalus and/or local brainstem compression may also benefit from more aggressive surgical treatment, as long as the conditions are reversible. Contrary to the general belief that outcome in survivors of space-occupying cerebellar stroke is usually good, recent studies suggest that for many of these patients, the long-term outcome is not good. In particular, advanced age and additional brainstem infarction seem to be predictors for poor outcome. Further trials are necessary to investigate these findings systematically and provide better selection criteria to help guide decisions about surgical therapies, which should always be carried out in close cooperation among neurointensive care physicians, neurologists, and neurosurgeons.

Clinical study of medial area infarction in the region of posterior inferior cerebellar artery

Our objective is to study the neurological characteristics of medial area infarction in the caudal cerebellum. Medial area of the caudal cerebellum is supplied with 2 branches of the posterior inferior cerebellar artery (PICA). The medial hemispheric branch of the PICA distributes to the medial area of the caudal cerebellar hemisphere. The medial branch of the PICA (mPICA) distributes to the inferior vermis. We studied the neurological characteristics of 18 patients with medial area infarction of the caudal cerebellum. The infarction was located in the medial area of the cerebellar hemisphere and vermis (medial ch/vermis) in 11 patients and in the medial area of the cerebellar hemisphere (medial ch) in 7 patients. All the 18 patients showed acute vertigo and disturbance of standing and gait at onset. On admission, the lateropulsion and wide-based gait were present in 13 patients, respectively. Mild ataxia of the extremities was shown in 7 patients. Acute vertigo and unsteadiness were prominent at onset in the 18 patients, although their ataxia of the extremities was mild or none. This result was consistent with the characteristics of medial area infarction of the caudal cerebellum. Comparing the neurological symptoms between the medial ch/vermis group and medial ch group, both lateropulsion and wide-based gait were significantly infrequent in medial ch group. This result indicated that the vermis was spared because the mPICA was not involved in the medial ch group. It is necessary to make a careful diagnosis when we encounter patients who present acute vertigo because truncal and gait ataxia are unremarkable on admission in patients with the medial area infarction of the caudal cerebellum without vermis involvement.

Bilateral Superior Cerebellar Artery Infarction after Stent-Angioplasty for Internal Carotid Artery Stenosis

Spontaneous bilateral cerebellar infarction in the territory of the superior cerebellar arteries is extremely rare. Occasionally there have been reports of bilateral cerebellar infarction due to vertebrobasilar atherosclerotic occlusion or stenosis, whereas no report of bilateral cerebellar infarction due to complicated hemodynamic changes. In this report, we present a patient with bilateral cerebral infarctions related to stenoses of bilateral internal carotid arteries, in whom vertebrobasilar system was supplied by multiple collaterals from both posterior communicating arteries and right external carotid artery. We performed stent-angioplasty of bilateral internal cerebral arterial stenosis, and then acute infarction developed on bilateral superior cerebellar artery territories. The authors assumed that the infarction occurred due to hemodynamic change between internal carotid artery and external carotid artery after stent-angioplasty for stenosis of right internal carotid artery.

Clinical outcome following surgical treatment for bilateral cerebellar infarction

OBJECTIVES

To analyze the initial clinical and radiological findings, the surgical treatment, and the clinical outcome following surgical decompression in patients with space-occupying bilateral cerebellar infarction.

MATERIALS AND METHODS

Ten patients with expansive bilateral cerebellar infarction and decreased level of consciousness were operated with suboccipital craniectomy, removal of the infarcted tissue, and placement of external ventricular drainage. Long-term outcome was assessed using the modified Rankin scale (mRS).

RESULTS

Mean Glasgow coma scale (GCS) score before surgery was 8.9 ± 3.3 and improved to 12.6 ± 3.6 at discharge. At the long-term follow-up (median 57.6 months), six patients had a favorable outcome (mRS 1.3 ± 0.8). Four patients, all with an associated brain stem infarct, had a poor outcome.

CONCLUSIONS

In the absence of brain stem infarcts, surgical treatment resulted in a favorable clinical outcome and should be considered a treatment option for patients with expansive bilateral cerebellar infarction.

Bilateral cerebellar infarction in the medial branches of posterior inferior cerebellar arterial territory—Using endoscopic third ventriculostomy to relieve acute hydrocephalus

Simultaneous bilateral cerebellar infarctions in posterior inferior cerebellar arterial (PICA) territory, without brain stem involvement are rare. We herein report a 51-year-old man developed sudden dizziness, nausea and vomiting. CT revealed hypodense bilateral lesions over the cerebellum corresponding to the medial PICA (mPICA) branch territory. His mental state deteriorated 2 days after onset; repeated CT showed severe third and lateral ventricular dilation. Endoscopic third ventriculostomy (ETV) was done to relieve the acute obstructive hydrocephalus. The patient was later discharged with only mild residual ataxia. Compared with conventional surgical treatments (external ventricular drainage, craniectomy and cerebellectomy), ETV has several advantages, including less risk and minimal invasiveness. However, further study is needed on its safety and efficacy under such circumstances.

Bilateral medial cerebellar infarction in a patient positive for lupus anticoagulant

Bilateral medial cerebellar infarction occurring simultaneously is rare. We describe a middle aged male with bilateral cerebellar infarction complicated by subsequent left superior cerebellar artery infarction. Lupus anticoagulant was positive. Though the prognosis is usually considered good, our patient made poor recovery.

The bihemispheric posterior inferior cerebellar artery

Rarely, a solitary posterior inferior cerebellar artery (PICA) will supply both cerebellar hemispheres. We report four cases of this variant. We present a retrospective review of clinical information and imaging of patients undergoing angiography at our institution to identify patients with a bihemispheric PICA. There were four patients: three males and one female. One patient presented with a ruptured arteriovenous malformation, and one with a ruptured aneurysm. Two patients had normal angiograms. The bihemispheric PICA was an incidental finding in all cases. The bihemispheric vessel arose from the dominant left vertebral artery, and the contralateral posterior inferior cerebellar artery was absent or hypoplastic. In all cases, contralateral cerebellar supply arose from a continuation of the ipsilateral PICA distal to the choroidal point and which crossed the midline dorsal to the vermis. We conclude that the PICA may supply both cerebellar hemispheres. This rare anatomic variant should be considered when evaluating patients with posterior fossa neurovascular disease.

Multiple Cerebellar Infarcts: Clinical and Pathophysiologic Features

We investigated the clinical features of 15 patients with multiple isolated ischemic lesions in the cerebellum. The main initial symptoms were vertigo and nausea/vomiting in 8 patients each, and headache in 6 patients. Dysarthria and cerebellar ataxia of the limbs and trunk were observed in 14 patients. The ischemic lesions were in the posterior inferior cerebellar artery (PICA) plus superior cerebellar artery (SCA) territories in 4 patients (27%), and PICA plus SCA plus anterior inferior cerebellar artery (AICA) territories in 3 patients (20%). Infarcts were in the AICA plus SCA territories in 2 patients (13%), PICA only in 2 patients (13%), and SCA only in 4 patients (27%). Hemorrhagic lesions were observed in the ischemic area in 2 patients (13%). Vascular lesions included occlusive lesions of the vertebral arteries in 9 patients (60%), but no abnormalities of the vertebrobasilar arterial system were observed in 6 patients (40%). The functional prognosis was good in most cases. The underlying mechanism was atherothrombotic, including arteriogenic embolism in 9 patients (60%) and cardiogenic embolism in 3 patients (20%). An embolic mechanism was considered in all cases, but in some cases an accurate pathogenesis of the cerebellar infarction was obscure.

Acute bilateral cerebellar infarction in the territory of the medial branches of posterior inferior cerebellar arteries

The most frequent type of cerebellar infarcts involved the posterior inferior cerebellar artery (PICA) and superior cerebellar artery territories but bilateral involvement of lateral or medial branches of PICA is extremely rare. In this report, we present a 55-year-old male who admitted to hospital with vomiting, nausea and dizziness. On examination left-sided hemiparesia and ataxic gait were detected. Infarct on bilateral medial branch of PICA artery territories was found out with cranial magnetic resonance imaging (MRI) technique and 99% stenosis of the left vertebral artery was found out with digital subtraction arteriography. The patient was put on heparin treatment. After 3 weeks, his complaints and symptoms had disappeared except for mild gait ataxia.

Bilateral cerebellar infarctions caused by a stenosis of a congenitally unpaired posterior inferior cerebellar artery

Bilateral symmetrical cerebellar infarcts in the territory supplied by the medial posterior inferior cerebellar artery (PICA) branches are extremely rare. In the few cases published, it has not been possible to clearly pinpoint the cause of this infarct pattern. The authors present the case history of a 58-year-old man who had acute headaches accompanied by pronounced rotatory vertigo with nausea and vomiting. The neurological examination revealed bilateral cerebellar signs. Cranial magnetic resonance imaging showed bilateral, nearly symmetrical infarcts in the territory of the medial branches of both PICAs. These bilateral PICA infarctions were caused by a stenosis of an unpaired PICA originating from the left vertebral artery supplying both cerebellar hemispheres.

Acute bilateral infarcts of the posterior inferior cerebellar artery

Acute bilateral infarcts in the territory of the posterior inferior cerebellum artery are rare and poorly documented in the literature. Thus, this report describes the clinical course and outcome in 3 patients. Although one was associated with coronary artery bypass surgery, the etiology was not known. Despite large territorial infarcts, the patients recovered to ambulation with minimal assistance.

Bilateral simultaneous cerebellar infarction in the medial branches of the posterior inferior cerebellar artery territories

We present an unusual case of simultaneous bilateral cerebellar infarction in the territory of the medial and intermediate branches of the posterior inferior cerebellar arteries (mPICA). The patient, a 57-yr-old woman, had no risk factors for cerebrovascular disease but a long-standing hypertension. Pathogenetic hypotheses of this unusual ischemic site of lesion may be referred to: A) two PICAs arising from an occluded basilar artery; B) both medial branches arising from the same PICA on one side; C) a haemodynamic mechanism with hypoperfusion in the most peripheral branches of the arteries; D) a double, simultaneous embolic stroke in mPICAs territory. Based on clinical course, supraortic duplex-scan, echocardiography, MRI, angioMRI and CT scans, and digital subtraction angiography, none of these hypotheses could be clearly associated with the pathogenesis of the lesion. Nevertheless, we propose that an anomalous common mPICA for both cerebellar territories should represent the necessary condition for the ischemic insult and, simultaneously, other factors should intervene as possible determining events.