Acute cerebellar infarction or hemorrhage may initially manifest in a clinically indolent

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NEUROLOGICAL REVIEW

SECTION EDITOR: DAVID E. PLEASURE, MD

Management of Acute Cerebellar Stroke

Matt B. Jensen, MD; Erik K. St. Louis, MD

A

cute cerebellar infarction or hemorrhage may initially manifest in a clinically

indo-lent manner only to later deteriorate into a life-threatening neurologic catastrophe.

At the other end of the spectrum, some patients with cerebellar stroke may present in

a moribund comatose state. In both patient groups, it is often unclear at what point

surgical intervention should be considered either to prevent further neurologic deterioration or to

try to salvage a meaningful neurologic recovery. In this review, we present clinical cases that

il-lustrate decision points in the management of patients with acute cerebellar stroke, with emphasis

on clinical and imaging characteristics. We conclude with an analysis of clinical decision making

in the management of patients with space-occupying cerebellar stroke. The management of acute

cerebellar infarction or hemorrhage often requires difficult and prompt decisions by treating

neu-rologists, and certain easily identifiable clinical and imaging findings may assist in appropriate

pa-tient triage and timely neurosurgical intervention.

Arch Neurol. 2005;62:537-544

Acute cerebellar infarction and hemor-rhage require constant vigilance by phy-sicians owing to often unpredictable clini-cal behavior. Cerebellar stroke may manifest with ataxia, vertigo, dysarthria, nausea, vomiting, and often a prominent headache. Rapid deterioration in these pa-tients is particularly vexing because of the difficulty in mobilizing neurosurgical in-tervention and the uncertainty regarding the mechanism of deterioration. It is also difficult to determine whether ensuing coma results from potentially reversible causes, such as evolving hydrocephalus, brainstem compression by mass effect, or irreversible brainstem infarction.

Data to aid clinical decision making are limited and largely focus on the final pa-tient prognosis rather than on prediction of neurologic deterioration or the effect of intervention on outcome. A few recent large retrospective and prospective case se-ries have attempted to address these is-sues, and they are reviewed herein in the context of illustrative cases. In this

ar-ticle, we present actual patient cases that show the clinical spectrum of cerebellar stroke, ranging from clinically stable pa-tients to moribund papa-tients who are co-matose at presentation. The effects of clini-cal signs and imaging results on practiclini-cal management are reviewed, and conclu-sions based on a review of the literature for guiding decision making are pre-sented.

PREDICTING NEUROLOGIC DETERIORATION IN INITIALLY STABLE PATIENTS Clinical Case 1: Cerebellar Infarction A 47-year-old man with hypertension, hy-perlipidemia, and diabetes mellitus devel-oped vertigo, nausea, and vomiting. This continued to a mild extent and then wors-ened 10 days later, with a brief episode of right hemi-numbness, right ear tinnitus, poor balance, and incoordination of the right hand that persisted. Magnetic reso-nance imaging showed bilateral cerebellar infarcts, right larger than left (Figure 1). Magnetic resonance angiography showed Author Affiliations:Department of Neurology, University of Iowa Hospitals and

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a small left vertebral artery and a high-grade stenosis in the right vertebral artery before the origin of the poste-rior infeposte-rior cerebellar artery. The patient was admitted to the hospital and was observed closely but had no clini-cal change. His symptoms resolved, except for clumsi-ness of the right hand, which gradually improved with physical therapy. He was given antiplatelet agents, and he achieved better risk factor control and was scheduled for a conventional angiogram with the possibility of endo-vascular intervention of his stenosis.

This case illustrates the value of serial clinical follow-up, which is best performed in a neurologic intensive care unit. Patients with cerebellar stroke should ideally be ad-mitted to a neurologic intensive care unit for 72 to 96 hours after first being seen to permit continuous neuroscience nursing staff observation and frequent physician reexami-nation. If the patient remains stable through the first few days, when infarct swelling is expected, further deteriora-tion from cerebellar infarcdeteriora-tion is unlikely. A similar

fore-cast is not always possible with cerebellar hemorrhage; the literature is replete with cases of neurologic deterioration days and even weeks after the clinical ictus of symptom on-set.1-4However, most patients with a cerebellar hematoma

who remain stable during the first 5 hospital days are un-likely to deteriorate, and they may be safely transferred to a ward setting with continued close observation.

Clinical Case 2: Cerebellar Hemorrhage

An 81-year-old woman with a history of hypertension, dia-betes mellitus, hyperlipidemia, myocardial infarction, is-chemic stroke, and atrial fibrillation treated with warfa-rin sodium developed nausea and vomiting, followed by vertigo, left-handed clumsiness, and difficulty walking. Head computed tomography (HCT) showed a 1- to 2-cm hematoma in the cerebellum just lateral to the vermis, with a small amount of intraventricular extension (Figure 2). Figure 1.Magnetic resonance image showing a bilateral cerebellar infarction (right⬎left). Note the lack of compression on the brainstem and fourth ventricle.

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Her anticoagulation was reversed. On transfer to the Uni-versity of Iowa Hospitals and Clinics, she was fully alert (Glasgow Coma Scale [GCS] score of 15), and the exami-nation findings were normal except for mild gait, left arm, and left leg ataxia and diminished sensation in a bilateral stocking distribution, with loss of ankle jerks. The next day the patient became progressively drowsy, with a new HCT showing hydrocephalus; ventriculostomy was per-formed. She returned to full alertness, and during the next few weeks her ataxia improved. She was discharged from the hospital in good condition.

Most data generated on cerebellar stoke have at-tempted to predict outcome. However, on hospital ad-mission, physicians are most concerned about the po-tential for a patient’s condition to deteriorate. In a large retrospective study1regarding the prediction of

neuro-logic deterioration in cerebellar hemorrhage, 46% of ini-tially alert patients (GCS score of 13-15) experienced de-terioration, with a decreasing level of consciousness, evolution of new brainstem signs, or worsened motor re-sponse on the GCS. Statistically significant clinical and imaging features that predicted neurologic deteriora-tion included a hospital admission systolic blood pres-sure greater than 200 mm Hg, pinpoint pupils, abnor-mal corneal or oculocephalic reflexes, extension of hemorrhage into the cerebellar vermis, a hematoma of 3 cm or greater, visible brainstem distortion on CT, the pres-ence of intraventricular hemorrhage, upward hernia-tion, and acute hydrocephalus. Multivariate analysis dem-onstrated that hemorrhage in the vermis and acute hydrocephalus independently predicted deterioration. Our patient had a small hemorrhage; however, it involved the vermis, with extension into the fourth ventricle.

The main differential diagnostic possibilities with de-teriorating cerebellar stroke are brainstem compression

by direct mass effect, evolution of obstructive hydro-cephalus from compression of the fourth ventricle, and occlusion of the cerebral aqueduct as a secondary phe-nomenon accompanying upward herniation of vermian cerebellar tissue through the tentorial notch.

The existing literature regarding the best approach to such deteriorating cerebellar stroke is relatively sparse and inconclusive. When the primary mechanism of neu-rologic deterioration seems to result from direct brain-stem compression, the literature suggests that definitive surgical management requires a suboccipital craniec-tomy with evacuation of the hematoma or resection of infarcted cerebellar tissue to relieve the directly offend-ing mass effect on the brainstem.2In addition, when

de-terioration seems to result from obstructive hydrocepha-lus alone and there is no obvious evidence of direct brainstem compression by clinical examination or im-aging findings, it remains unclear whether ventriculos-tomy alone may be adequate for the prevention of fur-ther deterioration or whefur-ther definitive resection should still be performed to relieve ventricular obstruction and brainstem compression. Some experts have advocated a staged approach, in which patients with deteriorating lev-els of consciousness, gaze palsy, or a herniation syn-drome have emergency HCT to determine whether the mechanism seems to primarily be evolving obstructive hydrocephalus, direct brainstem compression, or up-ward herniation.

If hydrocephalus seems to be the main mechanism re-sponsible for deterioration, a temporizing ventriculos-tomy can be considered. If the patient improves, no fur-ther surgical fur-therapy may be needed. If the patient does not improve, then a definitive posterior fossa decom-pressive suboccipital craniectomy should be urgently un-dertaken.5,6Because craniotomy carries an attendant

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evated risk of morbidity and mortality, when the patient’s clinical course of deterioration is relatively slow for sev-eral hours, a strategy of staged procedures with initial ven-triculostomy followed by craniectomy if necessary is rea-sonable. However, with more catastrophic and rapidly evolving neurologic deterioration, for less than an arbi-trary 8-hour limit, and when the risk of craniectomy is rela-tively low, such as in younger individuals, then primary craniectomy should probably be the treatment of choice.

Clinical Case 3: Cerebellar Infarction

A 48-year-old aerobics instructor, on traversing a step to the right while teaching a class, developed abrupt vertigo

and continued walking to the right until she reached the wall, which she leaned on for support. Her symptoms sub-sided, and she finished the class. That night she vomited twice. For the next 2 days she had a severe headache, mild vertigo, and a tendency to veer to the right while walk-ing. She was seen for the continued headache. Her neu-rologic examination findings were normal, except for fall-ing to the right with tandem gait. After CT, the patient underwent magnetic resonance imaging, which showed an infarct of the medial left lobe of the cerebellum (Figure 3). Magnetic resonance angiography showed oc-clusion of the left vertebral artery, with otherwise normal cerebrovasculature. Her headache improved, and she was discharged from the hospital.

This case demonstrates the potential discrepancy be-tween the size of a cerebellar infarct on imaging and the severity of the clinical course. The extent and location of the infarct made the possibility of hydrocephalus from obstruction of the fourth ventricle concerning enough to warrant hospital admission for close observation in ad-dition to evaluation for the etiology of her stroke. As it turned out, had she tolerated her headache for 1 more day, it is likely that no one would have ever known about the stroke. Many cases of mild cerebellar infarction prob-ably never reach medical attention.7

Clinical Case 4: Subdural Hemorrhage in the Posterior Fossa

A 57-year-old woman with mechanical aortic and mi-tral valves was admitted to the hospital for ischemic co-litis. She underwent hemicolectomy, before which war-farin sodium therapy was changed to heparin therapy. After a week of uneventful recovery she became progres-sively drowsy in a 24-hour period to the point of obtun-dation. Head CT showed bilateral subdural hematomas in the posterior fossa, with mass effect obliterating the fourth ventricle and basal cisterns, and hydrocephalus (Figure 4). Anticoagulant therapy was stopped. Poste-rior fossa craniectomy with evacuation of the hema-toma and ventriculostomy were performed (Figure 5). The patient returned to full alertness and did well neu-rologically, although she developed multiple medical com-plications that kept her in the intensive care unit.

This is an unusual case of a vascular event causing acute mass effect in the posterior fossa. It demonstrates many of the same clinical and imaging features as cerebellar stroke. The small volume of the posterior fossa allows Figure 3.Magnetic resonance image showing an infarct of the left cerebellum with narrowing of the fourth ventricle but no hydrocephalus.

Figure 4.Head computed tomographic scan showing bilateral subdural hematomas in the posterior fossa with hydrocephalus.

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even less room for a subdural hematoma than the supra-tentorial compartment. The ominous features of this case were progressive deterioration in the level of alertness, obliteration of the fourth ventricle and basal cisterns, and acute hydrocephalus. Surgical evacuation and ventricu-lar drainage prevented a likely fatal event in this patient.

CLINICALLY MORIBUND OR COMATOSE PATIENTS AT INITIAL EXAMINATION

The following cases demonstrate the opposite end of the clinical spectrum, when patients with a cerebellar stroke are in a comatose state on initial examination. The over-riding issue in such patients is determining neurologic salvageability and avoiding futile surgical intervention.

Clinical Case 5: Cerebellar Hemorrhage

A 56-year-old man began to feel unwell at a fair and was taken to a local emergency department. During the course of several hours he became comatose and was intu-bated. A noncontrast HCT showed a 5-cm hematoma in the right cerebellar hemisphere, with extension into the vermis and the fourth ventricle, acute hydrocephalus with blood present in all 4 ventricles, and effacement of the basal cisterns (Figure 6). He was given mannitol and was transferred to the University of Iowa Hospitals and Clinics. On initial examination, the patient was coma-tose (GCS score of 4) and intubated; his pupils were 3 mm and nonreactive, and corneal reflexes were absent. He had spontaneous cough. There was no motor re-sponse except decerebrate posturing of the right arm. A right frontal ventriculostomy and a suboccipital crani-otomy with posterior fossa clot evacuation were per-formed. After surgery, there was lability of blood pres-sure and heart rate and increasing pupillary size without reaction. A new HCT showed a large fourth ventricle full of blood and upward transtentorial herniation (Figure 7). He was taken back to the operating room for reevacua-tion and decompression. After the second operareevacua-tion there was no cough, gag, or brainstem reflexes or motor re-sponses. The family decided to withdraw life support, and the patient died.

Clinical Case 6: Cerebellar Hemorrhage

A 66-year-old man experienced the worst headache of his life and became unresponsive within hours. He was intubated and then defibrillated and resuscitated after ven-tricular tachycardia. An HCT showed a 4-cm hematoma in the left cerebellar hemisphere, with compression of the fourth ventricle, blood in the third and lateral ven-tricles, perihematoma hypodensity, a suggestion of up-ward herniation, and obliteration of the basal cisterns (Figure 8). His GCS score was 3, and his blood pres-sure was 67/50 mm Hg. He was administered vasopres-sors and was transferred to the University of Iowa Hos-pitals and Clinics. On arrival, the patient was comatose and intubated, with pupils mid-position and fixed and

bilateral vitreal hemorrhages. There were no corneal, gag, oculocephalic, or motor responses. There were no spon-taneous respirations. His family decided to withdraw life support, and the patient died.

CASE DISCUSSION

These cases are included in our discussion of space-occupying cerebellar stroke to point out that not all pa-tients with deterioration have a reversible mechanism. Taneda et al8described 3 patient groups with acute

cer-ebellar stroke causing coma that vary by their clinical pre-sentation, course, and neuroradiologic appearance:

1. Alert at onset, with paroxysmal cerebellar symp-toms and signs and subsequent stabilization for 10 to 36 hours, and then rapid and progressive deterioration of consciousness in 2 to 18 hours. This group was usually found to have a syndrome of progressive direct brain-stem compression by the expanding hematoma or edema. 2. Sudden cerebellar symptoms with rapid deterio-ration of consciousness, representing hemorrhage into a cerebellar infarct. These patients present with a cer-ebellar hematoma, with a subsequent diagnosis of ische-mic infarction as the pathogenic mechanism made only at the time of surgery or autopsy.

3. Sudden unresponsiveness and coma within hours of symptom onset, without substantial further deterio-ration. This was found to almost universally result from extensive concurrent brainstem infarction at the time of cerebellar hermorrhage or infarction, as was likely seen in our case 6 described previously. Amarenco9also found

that in patients with a hemiplegia or a tetraplegia, often a massive comorbid paramedian pontine infarction rather Figure 5.Head computed tomographic scan of the same patient shown in Figure 4 after craniectomy, evacuation, and ventriculostomy.

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Figure 6.A noncontrast head computed tomographic scan showing a large hematoma with vermis involvement, blood in all of the ventricles, hydrocephalus, and loss of the prepontine and quadrigeminal cisterns.

Figure 7.Despite hematoma evacuation, another computed tomographic scan of the patient in Figure 6 shows the persistence of basal cistern effacement, hydrocephalus, and upward herniation.

Figure 8.A head computed tomographic scan showing a large hematoma that obliterates the fourth ventricle, with loss of the basal cisterns, hydrocephalus, and upward herniation.

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than brainstem compression was responsible for their deterioration.

Several retrospective studies3,10-14 have analyzed

clinical and imaging features that are predictive of poor outcome in cerebellar hemorrhage. Clinical features on hospital admission in patients with cerebellar hemor-rhage previously correlated with a poor outcome have included systolic blood pressure greater than 200 mm Hg (presumed to be part of the Cushing response),4

gaze paresis,4,15,16and a decreased level of

conscious-ness,11,12,15-18which are all indications of compression at

the pontine level. The CT scan features indicative of a poor prognosis are a midline location,13,15,19-21an

oblit-erated fourth ventricle and basal cisterns,1,13,19,22

up-ward herniation,8,23intraventricular hemorrhage,24and

hydrocephalus.2,4,18,23A widely accepted neurosurgical

adage is to evacuate a cerebellar hemorrhage that is more than 3 cm in cross-sectional diameter by CT scan, but, as seen in our patient, the outcome remains poor in many patients, and clinical criteria must enter into the decision making.

One retrospective study25of patient outcomes in

cer-ebellar hemorrhage identified clinical and imaging fea-tures predictive of poor outcome. Predictors of disabil-ity included a hospital admission systolic blood pressure greater than 200 mm Hg, a hematoma size greater than 3 cm in diameter, visible brainstem distortion, and acute hydrocephalus on hospital admission CT. Significant pre-dictors of death were abnormal corneal and oculoce-phalic reflexes, a GCS score less than 8, motor response less than localization to pain, acute hydrocephalus, and intraventricular hemorrhage on CT. An absent corneal reflex on hospital admission was found to be highly pre-dictive of poor outcome. The best outcomes were in pa-tients younger than 70 years with normal corneal re-flexes. After adjustment for confounding factors, coma on hospital admission (GCS score⬍8) and intraven-tricular hemorrhage were independently predictive of death. Although retrospective data are subject to bias, the clinical and imaging features identified may help curtail the generation of unrealistic hope and may affect discus-sions regarding prognosis and intervention with family members.

SUGGESTIONS FOR CLINICAL DECISION MAKING IN PATIENTS

WITH CEREBELLAR STROKE

These cases illustrate the range of clinical presentations and courses in patients with cerebellar stroke. There are many retrospective studies and a few prospective obser-vational trials that are helpful in guiding clinical deci-sion making. In the absence of data from a randomized controlled trial, a reasonable framework for patient care has been suggested by Kirollos et al,24who treated 50

con-secutive patients using a protocol based on the appear-ance of the fourth ventricle and the GCS score. If the fourth ventricle was completely effaced, the patient underwent surgical evacuation and ventricular drainage. If the fourth ventricle appeared normal, the patient was treated con-servatively, unless the GCS score deteriorated, in which

case the patient underwent ventricular drainage. If the fourth ventricle was compressed (but not completely ef-faced), the patient was treated conservatively if fully alert, shunted if the GCS score deteriorated and lus was present, or evacuated if there was no hydrocepha-lus (or if the GCS score did not improve with shunting). Mortality at 3 months was 40% (a sizeable proportion from medical issues). Of the survivors, 80% had a good outcome (independent in activities of daily living, with a Glasgow Outcome Scale score of 4 or 5). None of the patients with a completely effaced fourth ventricle and coma (GCS score⬍8) survived with a good outcome. In this analysis by Kirollos et al,24outcome correlated best

with fourth ventricular grade (P⬍.002) and preopera-tive GCS score (P⬍.003). Their data suggested that patients did better if they underwent surgery before de-terioration.

CONCLUSIONS

The clinical and imaging features of patients with cer-ebellar stroke can be helpful in clinical decision mak-ing. No single clinical or imaging finding can be used in isolation when deciding whether to use aggressive sur-gical management or to withhold such therapy; the over-all clinical gestalt of the patient with cerebellar stroke re-mains paramount.

During the patient’s first week in the hospital, obser-vation in a neurologic intensive care unit may facilitate the timely recognition of neurologic deterioration and permit immediate repeated imaging to guide an appro-priate and tailored surgical approach. Ventriculostomy may be an adequate temporizing measure in the patient with deterioration predominantly resulting from obstruc-tive hydrocephalus, whereas definiobstruc-tive treatment of pro-gressive brainstem compression most often requires cra-niectomy for decompression of the posterior fossa.

Patients with declining levels of consciousness, new brainstem signs (particularly loss of corneal reflexes), evolving hydrocephalus, and midline cerebellar stroke are at increased risk for deterioration and poor out-come. Whether prophylactic ventriculostomy or decom-pression prevents neurologic deterioration is not clear, and this issue should be addressed in a randomized con-trolled trial; perhaps diffusion-perfusion magnetic reso-nance imaging could contribute to a better understand-ing of the importance of infarct volume or ischemic penumbra on the risk of subsequent deterioration and poor outcome.

Accepted for Publication:April 20, 2004.

Correspondence:Erik K. St Louis, MD, Department of Neurology, University of Iowa Hospitals and Clinics, 200 Hawkins Dr, Iowa City, IA 52242 (erik-stlouis@uiowa .edu).

Author Contributions:Study concept and design:Jensen and St Louis.Acquisition of data:Jensen and St Louis.

Analysis and interpretation of data:Jensen and St Louis.

Drafting of the manuscript:Jensen and St Louis.Critical revision of the manuscript for important intellectual con-tent: Jensen and St Louis.Administrative, technical, and material support:Jensen.Study supervision:St Louis.

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