Clozapine-Induced Refractory Colonic Pseudo-Obstruction

Abstract

The management of treatment-resistant schizophrenia (TRS) is challenging as the medications involved, often atypical antipsychotics, have a host of associated adverse effects. While complications such as agranulocytosis are well established and necessitate close hematological monitoring, the gastrointestinal effects of particular atypical antipsychotics, such as clozapine, are recognized to a lesser extent. The following case of TRS leading to chronic treatment-resistant pseudo-obstruction, eventually requiring total colectomy, highlights the considerable sequelae of clozapine on the gastrointestinal tract. Beyond the effects of severe constipation, the possible implications of ischemic colitis, stercoral perforation, and intraabdominal sepsis warrant a degree of caution when prescribing such medication. This study sheds light on the importance of monitoring bowel motility when administering antipsychotics, particularly clozapine, to avoid these deleterious consequences.

Keywords: clozapine; colectomy; colonic pseudo-obstruction; pseudo-obstruction; refractory pseudo-obstruction.

Figure 1. Stercoral colitis with marked distension of the rectum and mild distension of the sigmoid and ascending colon with fecal material.

No evidence of perforation was noted.

Figure 2. The stomach and proximal jejunum are mildly distended with fluid.

A short segment of the small bowel fecalization distal to this suggests slow transit. The fecalized small bowel loop appears to gradually taper and a definite transition point is not identified.

Figure 3. Intraoperative image showing large redundant colon with loss of haustra.