Case Presentation: A 62-year-old male presented to the emergency department with altered mental status and fever. Computed tomography of the head showed enlargement of the left lateral ventricle. Magnetic resonance imaging demonstrated debris and purulence in the ventricle along with edema and transependymal flow of cerebrospinal fluid surrounding both ventricles.

Discussion: The patient was diagnosed with ventriculitis. Ventriculitis is an uncommon but serious disease. Early recognition and treatment are essential.