A 42-year old obese, smoker and schizophrenic male was medicated with 600 mg of clozapine per day. He was admitted to the emergency department with a 2 week history of diffuse abdominal pain, abdominal distention, anorexia and semi-liquid stools. On physical examination he had 110/63 mmHg of blood pressure, he was tachycardic (heart rate = 112 beats per minute), febrile (temperature = 38.5  C) and presented abdominal tenderness and peritoneal sign.
Laboratory investigations showed a hemoglobin of 13.6 g/dl, an increase in inflammatory markers (white blood cells 13.2 x 109/l, C-reactive protein >32 mg/dl) and a renal insufficiency (creatinine 3.02 mg/dl, urea 189 mg/dl).
An upright abdominal X-ray demonstrated a pneumoperitoneum which was confirmed by the abdominal and pelvic computerized tomography (Figs. 1 and 2 ).
He was subjected to an emergency laparotomy where multiple punctiform perforations (holes smaller than 1 cm) in the anti-mesenteric border of the distal jejunum and ileum were identified. Purulent peritonitis was present. A small bowel resection of 1.5 m was done (Figs. 3 and 4 ).
On the second day of the postoperative period, an anastomosis dehiscence was registered. A subsequent re-laparotomy was needed. An anastomosis and caecum resection was done with the creation of an end-ileostomy and a colostomy. During hospitalization he had a respiratory tract infection which was treated with broad-spectrum antibiotics and an intra-abdominal abscess which was treated with percutaneous drainage. On the 28th day of hospitalization the patient was discharged.
Histologic specimens revealed non-specific inflammatory findings with ischemia.
The investigation was carried out with microbiologic cultures, serologic tests, laboratory tests, endoscopic exams with biopsies and other diagnostic exams. The main causes of spontaneous small bowel perforation were excluded, such as, infectious (cytomegalovirus, tuberculosis, bacterial, parasitic and protozoal), immune (Crohn's disease, celiac or gluten-sensitive enteropathy and vasculitis), congenital (Meckel diverticulum and small bowel diverticulum or duplication), vascular and neoplastic.
The dose of clozapine was reduced because the suspension was not viable and a restoration of the bowel continuity was done ten months later.