Background: A 58-year-old schizophrenic male who had been drinking at least 4-5 l of pure water every day for 30 years was admitted to a hospital with complaints of nausea, fatigue, and irregular, fluctuating fevers (up to 39 degrees C). He had previously been prescribed fluoxetine at a dose of 20 mg/day and had been using the drug for 28 days.
Investigations: Review of medical history, physical examination, blood analysis, urine analysis, chest radiography and abdominal ultrasound.
Diagnosis: Psychogenic polydipsia and fluoxetine-induced syndrome of inappropriate antidiuretic hormone secretion.
Management: Fluid restriction and discontinuation of fluoxetine.