An otherwise healthy 12-year-old male presented with severe headache over the past two months. The headaches seemed progressive and were associated with fever. The child reported severe headache with nausea and vomiting on the day of hospitalization.There was no history of photophobia or neck stiffness. On examination, the child did not elicit an abnormal eye movement or gait. The vital signs were stable.Computed tomography (CT) scan imaging revealed obstructive hydrocephalus along with diffuse cerebellar swelling compressing the fourth ventricle. The cerebellar tonsils were slightly depressed.Neurosurgery was planned for cerebrospinal fluid (CSF) diversion with the insertion of a ventriculoperitoneal (VP) shunt, based on the diagnosis of acute hydrocephalus precipitated due to acute post-infectious cerebellitis.The follow-up magnetic resonance imaging (MRI) 24 hours after the VP shunt insertion depicted regression of the hydrocephalus. The patient was prescribed acyclovir 20 mg/kg/dose TID, vancomycin 20 mg/kg/dose QID, and ceftriaxone 50 mg/kg/dose BID. However, all blood/CSF cultures revealed negative results. Thereafter, pulse steroid therapy 30 mg/kg daily for 3 days was prescribed, along with intravenous immunoglobulin (IVIG) 1 gm/kg for 2 days, for treating the fulminant cerebellitis.This led to clear clinical and radiological improvement. A follow-up MRI confirmed resolution and normalization of cerebellar structures. There were no major sequelae at the three-month checkup. Source: The American Journal of Case Reports. 2021 Jan 17;22:e928370. doi: 10.12659/AJCR.928370.