A 76-year-old man presents to the emergency department because of several episodes of maroon-colored stools over the past 24 hours. He reports mild fatigue but denies abdominal pain, nausea, vomiting, or recent changes in bowel habits. His medical history is significant for hypertension, chronic kidney disease, and severe aortic stenosis. Medications include lisinopril, empagliflozin, and aspirin. Temperature is 36.9°C (98.4°F), blood pressure is 118/72 mm Hg, pulse is 96/min, and respiratory rate is 16/min. Physical examination is notable for conjunctival pallor and a systolic crescendo-decrescendo murmur at the right upper sternal border. The abdomen is soft and nontender. Laboratory studies reveal the following:
Colonoscopy demonstrates several flat, tortuous vascular lesions in the cecum and ascending colon without evidence of malignancy.
Which of the following is the most likely cause of this patient’s gastrointestinal bleeding?
The correct answer is:
A) Angiodysplasia
This patient has angiodysplasia, a common cause of lower gastrointestinal bleeding in older adults. The diagnosis is suggested by painless intermittent bleeding, iron deficiency-type anemia (microcytic), advanced age, and the characteristic vascular ectasias visualized on colonoscopy. The lesions are most commonly located in the cecum and ascending colon, as seen in this patient.
Angiodysplasia consists of dilated, fragile submucosal blood vessels that develop over time due to intermittent obstruction of venous drainage within the bowel wall. These lesions are prone to recurrent bleeding, which may present as occult blood loss causing iron deficiency anemia or as overt hematochezia. Bleeding is often intermittent because the lesions can thrombose and recanalize spontaneously.
An important Step 2 association is the relationship between angiodysplasia and aortic stenosis, known as Heyde syndrome. Patients with severe aortic stenosis develop increased shear stress across the stenotic valve, which promotes degradation of high-molecular-weight von Willebrand factor multimers. The resulting acquired von Willebrand disease increases the risk of bleeding from fragile vascular lesions such as angiodysplasias.
Management depends on the severity of bleeding. Active bleeding identified during colonoscopy can often be treated with endoscopic coagulation techniques such as argon plasma coagulation. Recurrent or severe cases may require angiographic or surgical intervention.
Answer choice B: Colorectal adenocarcinoma, is incorrect.
Colorectal cancer can cause chronic occult blood loss and iron deficiency anemia, making it a reasonable consideration. In this case, colonoscopy directly identified vascular malformations rather than a mass lesion. Additionally, colorectal cancer is less likely to cause intermittent painless bleeding of this nature.
Answer choice C: Diverticular bleeding, is incorrect.
Diverticular bleeding is another common cause of painless lower GI bleeding in older adults. However, colonoscopy would demonstrate diverticula rather than vascular ectasias. Diverticular bleeding also lacks the classic association with aortic stenosis.
Answer choice D: Ischemic colitis, is incorrect.
Ischemic colitis typically presents with acute abdominal pain followed by hematochezia. The absence of abdominal pain and the colonoscopic findings make this diagnosis unlikely.
Answer choice E: Ulcerative colitis, is incorrect.
Ulcerative colitis causes chronic inflammatory diarrhea, often accompanied by abdominal cramping, urgency, and diffuse mucosal inflammation on colonoscopy. This patient’s findings are more consistent with a vascular source of bleeding.
Key Learning Point
Angiodysplasia is a common cause of painless lower gastrointestinal bleeding in older adults and is classically associated with aortic stenosis (Heyde syndrome). Colonoscopy often reveals vascular ectasias in the cecum or ascending colon.
