A 65-year-old woman comes to the office due to gastrointestinal bleeding. She has had 3 or 4 episodes of dark maroon-colored stools in the last 2 weeks, with normal intervening bowel movements. The patient has no associated abdominal or rectal pain, nausea, or vomiting. She has a history of hypertension, type 2 diabetes mellitus, and hypercholesterolemia. Her temperature is 36.7 C (98 F), blood pressure is 140/80 mm Hg, pulse is 95/min, and respirations are 16/min. Physical examination reveals a 3/6 systolic ejection murmur in the right second intercostal space. Carotid pulses are delayed on palpation bilaterally. Abdominal and rectal examinations are benign. Laboratory results are as follows:
Hemoglobin 11.1 g/dL Mean corpuscular volume 90 µm3 Blood urea nitrogen 34 mg/dL Creatinine 1.6 mg/dL
Colonoscopy 6 months earlier was unremarkable but was somewhat limited in the ascending colon due to suboptimal bowel preparation. Which of the following is the most likely cause of this patient's symptoms?
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This clinical presentation of episodic painless gastrointestinal (GI) bleeding suggests angiodysplasia. Angiodysplasia is characterized by dilated submucosal veins and arteriovenous malformations, and has an increased incidence after age 60. It may occur anywhere in the GI tract but is most common in the right colon. Angiodysplasia is more frequently diagnosed in patients with advanced renal disease and von Willebrand (vW) disease, possibly due to the bleeding tendency associated with these disorders. Angiodysplasia may also be more common in patients with aortic stenosis (AS), possibly due to acquired vW factor deficiency (from disruption of the vW multimers as they traverse the turbulent valve space induced by AS). Angiodysplastic bleeding has been reported to remit following aortic valve replacement.
Diagnosis of angiodysplasia is usually made on endoscopic evaluation (eg, upper GI endoscopy, colonoscopy). However, it is not uncommon for angiodysplasia to be missed on colonoscopy due to poor bowel preparation or location behind a haustral fold. Asymptomatic patients do not require treatment. Patients with anemia or gross or occult bleeding can be treated endoscopically, usually with cautery.
(Choice B) Colon cancer can cause painless chronic bleeding. However, a cancer capable of causing gross bleeding (as seen in this patient) is unlikely to have been missed on colonoscopy and would likely have led to microcytic anemia (with mean corpuscular volume <80/µm3). It is more likely that angiodysplasia rather than colon cancer would be missed on colonoscopy.
(Choice C) Diverticulosis is also unlikely to have been missed on colonoscopy. In addition, bleeding from diverticula is frequently arterial, and typically results in passage of bright red blood. Maroon-colored stools are more characteristic of right colonic angiodysplasia.
(Choice D) Hemorrhoids cause bright red rectal bleeding, with blood on the surface of the stool or dripping into the toilet. They are usually apparent on rectal examination or during colonoscopy.
(Choice E) Ischemic colitis usually presents with sudden onset of abdominal pain and tenderness followed by rectal bleeding or bloody diarrhea within 24 hours. This patient has no abdominal pain.
Educational objective:
Angiodysplasia is characterized by dilated submucosal veins and arteriovenous malformations. It is a common cause of recurrent, painless gastrointestinal bleeding. Diagnosis is made on colonoscopy, although it is frequently missed. Asymptomatic patients do not require treatment. Those with anemia or bleeding can be treated with cautery.