Acute Cerebellitis Complicated by Hydrocephalus and Impending Cerebral Herniation

We present a 7-year-old boy with acute cerebellitis who required an emergency ventriculoperitoneal shunt for hydrocephalus caused by cerebellar swelling. This represents a very unusual, potentially life-threatening complication of a usually self-limiting condition. Early diagnosis of this complication is essential in view of the propensity to sudden and fatal deterioration. Magnetic resonance imaging (MRI) is useful in differentiating this unusual course of acute cerebellar ataxia from that of a posterior fossa tumor. In developing countries, however, computed tomography (CT) is often the only existing diagnostic modality, and access to MRI, when available, is limited. Our case demonstrates that the shape of the fourth ventricle on CT can be helpful in differentiating between a tumor and edema of the cerebellum and thus can assist in management.