Angiodysplasia--an uncommon cause of colonic bleeding: colonoscopic evaluation of 1,050 patients with rectal bleeding and anaemia.

Angiodysplasia of the colon was diagnosed in 31 out of 1,050 patients (3%) presenting with rectal bleeding or anaemia, among 10,000 colonoscoped at St. Mark's Hospital. The lesions were identified in 16 out of 879 (2%) patients with rectal bleeding, in 15 out of 171 (9%) patients with anaemia, and in a further three patients without features of blood loss. The angiodysplasia lesions were predominantly in the right colon (76%) and occurred with a similar frequency (12%) in the transverse and the left colon. Affected patients (59% male and 41% female) were in the older age group (53-89 years; mean age 69.5 years) but only one patient had known aortic valve disease. Angiodysplasia is an important diagnosis to consider in patients presenting with colonic bleeding or anaemia because it can be treated in the majority of cases by endoscopic electrocoagulation. However in our experience it is less common (3%) than previously suggested by other authors (40-67%). Endoscopic over-diagnosis is possible when intramucosal capillaries with no bleeding tendency on local traumatisation or biopsy are included in the diagnosis but these lesions are not true angiodysplasia.