Cerebellar Mutism and Reversible Cytotoxic Edema in Influenza B-Associated Encephalopathy

BACKGROUND: Influenza virus associated neurological complications are rare, though well-documented, especially in children. Encephalopathy and seizures are the most common complications and are typically associated with influenza A infection. Cerebellar mutism has been rarely reported in association with influenza B infection. PATIENT: We describe a 3-year-old boy who presented with cough, fever, altered mental status, seizure, hypotonia, and mutism. He tested positive for influenza B virus. His brain magnetic resonance imaging showed reversible cytotoxic edema limited to the middle cerebellar peduncles and the dentate nuclei. Other viral, vascular, toxic, and metabolic causes were ruled out. CONCLUSION: Our patient represents a case of cerebellar mutism associated with influenza B encephalopathy in which the brain magnetic resonance imaging scan showed reversible cytotoxic edema limited to the middle cerebellar peduncles and the dentate nuclei. This clinicoradiological correlation supports other reports in which the dentate nuclei play a major rule in the pathogenesis of cerebellar mutism.