Frequency, Aetiology, and Outcome of Small Cerebellar Infarction

<b><i>Background and Purpose:</i></b> Strokes due to small (&#x3c;2 cm) cerebellar infarction are under-recognised, and their profile and aetiology have not been well characterised. We aimed to determine the frequency, clinical features, aetiology, and outcome of small as compared to large cerebellar infarction. <b><i>Methods:</i></b> This study is a retrospective analysis of clinical and imaging features of a prospectively assessed series of 108 consecutive patients with acute cerebellar infarction admitted to Liverpool Hospital, Sydney, NSW, Australia, during 2011–2015. <b><i>Results:</i></b> The mean age of the patients was 67 years, and 33 (31%) had small cerebellar infarction. Compared to large cerebellar infarction, those with small cerebellar infarction had a comparable distribution of vascular risk factors but significantly less nausea and vomiting, gait disturbance, limb ataxia, and dysarthria. The posterior (<i>n</i> = 22, 67%) lobe was most commonly affected, followed by the anterior (<i>n</i> = 9, 27%) and flocculonodular (<i>n</i> = 2) lobes. Dizziness, limb ataxia, and nystagmus were significantly more common in patients with anterior lobe infarction. Vertebrobasilar disease was the presumed aetiology in 40 patients (37%), and was less commonly seen in small as compared to large cerebellar infarction. Cardioembolism affected 37% of the patients, irrespective of the size or topography of the cerebellar infarction, and there was no relation of supratentorial white matter lucencies (WMLs) to the size of cerebellar infarction. At 3 months, 65% of the patients were functionally independent (according to modified Rankin Scale scores of 0–2), and having a poor outcome was significantly related to moderate-to-severe supratentorial WML and large cerebellar infarction. <b><i>Conclusions:</i></b> Small cerebellar infarction accounted for one-third of the ischaemic strokes in this location, most often involved the posterior lobe, causing fewer clinical features, and had a better clinical outcome than large cerebellar infarction. Patients with small cerebellar infarction require appropriate vascular management including investigation for a cardioembolic source.