Meningitis or madness: a delicate balance.

A child with meningitis who developed a psychosis 2 weeks after commencing treatment with antituberculous therapy is described here. The psychosis resolved with cessation of isoniazid, but the meningitis returned. The meningitis was treated by re-introduction of daily doses of isoniazid, but the psychosis recurred. Successful treatment of the meningitis, with minimal psychotic symptoms, eventually was achieved using isoniazid at 48 h dose intervals. The psychosis resolved completely after completion of therapy for tuberculous meningitis and cessation of isoniazid. This is the first case of isoniazid-associated psychosis reported in a child.