Cerebellar infarction: natural history, prognosis, and pathology.

Using clinical and computed tomography (CT) criteria, an analysis of 2,000 consecutive stroke unit patients from 1977 to 1984 revealed 30 patients with cerebellar infarction. The case fatality rate was 23%, higher than for any other location of brain infarction studied over the same period. Death was most often due to concomitant brainstem infarction. Obstructive hydrocephalus occurred in 4 patients (13%), and in 2 cases diagnosis, facilitated by urgent CT scanning, allowed early surgical intervention that was life saving. Patients who survived the acute phase were followed for an average of 21 months, and over that time 22% sustained further brainstem infarction, representing a 13% stroke rate per year. Over the latter 3 years of the clinical study, an autopsy survey revealed 11 cases of cerebellar infarction that had been clinically unrecognized. None of these died as a direct result of their infarction. Mechanisms of infarction inferred from autopsy included in situ thrombosis, embolism, watershed, and lacunar infarction, with in situ thrombosis being the most common. We conclude that the case fatality rate of cerebellar infarction is greater than of any other form of brain infarction, but it may be reduced by prompt recognition of those patients who will benefit from surgical decompression. In survivors, a high risk of subsequent hindbrain stroke exists. More attention needs to be paid to this entity in terms of early diagnosis and prevention of subsequent stroke.