Question 134

Question:

A 33-year-old woman presents complaining of painless rectal bleeding. On three occasions in the last six months, she has noticed a moderate amount of red blood in the toilet after a bowel movement. She denies abdominal pain, constipation, diarrhea, and weight loss. On exam, you notice telangiectasias of her lips and oral mucous membranes. On questioning, she reports that her father also has similar “red spots” on his lips. Rectal exam reveals no mass and no gross blood but she is guaiac positive. What is the most likely source of her bleeding?

Correct Answer: A.  Arteriovenous malformation

This woman has Osler-Weber-Rendu syndrome (or hereditary hemorrhagic telangiectasia), an autosomal dominant disorder characterized by telangiectasias and arteriovenous malformations (AVMs) of the mucous membranes and the GI tract. A colonic AVM could result in intermittent episodes of rectal bleeding. AVMs are a fairly common cause of GI bleeding, and the majority of patients who have them do not have Osler-Weber-Rendu syndrome. Colon cancer (B) usually presents in an older patient (screening colonoscopy should be started at age 50), unless the patient has familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC) – there is no family history in the question stem suggesting either of these. Diverticulosis (C) can cause painless rectal bleeding but would be very rare in a patient this young. Infectious colitis (D) would be associated with diarrhea and crampy abdominal pain, and is inconsistent with the six month time frame. Ulcerative colitis (E) would also be associated with diarrhea and abdominal pain.