Small bowel causes of per rectum haemorrhage.

: The majority of cases of per rectal haemorrhage (PRH) are due to colorectal causes within the diagnostic reach of the colonoscope. However a few cases are from the small bowel which may pose difficulty and delay in diagnosis. We reviewed 1489 patients with PRH from 1989 to 1993 and identified 10 cases of bleeding originating from the small bowel (0.7%). These were diagnosed when both the colonoscopy and upper gastrointestinal endoscopy were negative or by observing blood coming through the ileo-caecal valve. The causes were Meckel's diverticulum (4), leiomyoma (1), intussusception (1), lymphoma (1), carcinoma (1), Crohn's disease (1) and vasculitis (1). Six cases presented with active bleeding and haemodynamic instability; 4 had chronic bleeding associated with anaemia. Bleeding from Meckel's diverticulum could be differentiated by age, mid-20s or younger compared with mid-40s or older of non-Meckel's cases. Small bowel causes need to be considered in PR bleeding unexplained on colonoscopy and oesophagogastroduodenoscopy findings. A 99mtechnetium isotope scan is most likely to be of help in the young adult but from mid-life onwards, however, other techniques such as small bowel barium studies are required.