Does painless rectal bleeding equate to a colonic polyp?

BACKGROUND: It is often stated that if a patient presents with 'painless rectal bleeding' then a rectal polyp is the probable diagnosis. The aim of this study is to review our experience of children undergoing endoscopy to assess if the above statement is correct.

METHODS: The senior author keeps a prospective database of every child undergoing flexible sigmoidoscopy or colonoscopy. As part of this database, the symptoms and signs that the patient presents with, specifically abdominal pain, diarrhoea, mucous per rectum and rectal bleeding, are recorded. These results have been analysed specifically to assess whether the opening statement is correct.

RESULTS: Between 2000 and 2014, a total of 401 children have undergone flexible sigmoidoscopy (21) or colonoscopy (380) to investigate rectal bleeding. Of these 401 patients, 42 (10.5%) had at least one polyp. Four polyps (9%) occurred in 159 patients with no rectal bleeding during the study period. The remaining 42 polyps (91%) were identified in patients with rectal bleeding. Of these 42 polyps, painless rectal bleeding was the only symptom in 24 (57%). However, 123 patients were endoscoped with painless rectal bleeding alone, giving a polyp rate of 19.5% for this symptom. The polyp pickup rate was increased to 28% if rectal bleeding and mucous per rectum were present; however, only 25 patients had this clinical history.

CONCLUSION: We confirm that the most common symptom of rectal polyps is painless rectal bleeding. However, only one in five patients with this clinical history has a rectal polyp at endoscopy. The polyp pickup rate at endoscopy is greater (28%) when a history of both rectal bleeding and mucous per rectumispresent. This information can be used to counsel parents preoperatively.