An acute arboviral infection caused by a virus of the <i>Flaviviridae</i> family transmitted by an infected mosquito, and characterized by the onset of flulike symptoms such as fever, malaise, headache, cough, and sore throat that can progress to meningitis or encephalitis with symptoms like nausea, vomiting, confusion, stiff neck, disorientation, irritability, tremors, and convulsions. Photophobia, cranial nerve palsies, and even coma may occur.
Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation.
Etiologies included hypoxic-ischemic encephalopathy; haloperidol treatment with and without neuroleptic malignant syndrome; toxicity of cytosine arabinoside, cyclophosphamide, amphotericin B, and methotrexate; St. Louis encephalitis and other encephalitides; and a pineal tumor with hydrocephalus.