Dehn T, McGinn F P
Postgrad Med J. 1982 Feb;58(676):92-3. doi: 10.1136/pgmj.58.676.92.
The causes of ano-rectal bleeding as the only symptom in 110 patients were studied. A diagnosis was obtained in 77% of patients after clinical examination, sigmoidoscopy and proctoscopy, increasing to 97% after radiology and colonoscopy. Anal causes of bleeding were found in 81% of the patients, while a source in the rectum or colon accounted for only 16%.