A 65-year-old man comes to the emergency department after 2 episodes of bloody bowel movements. The patient felt well until approximately 3 hours ago when he had a sudden urge to defecate, followed by passage of a large amount of bright red blood. He had another small amount of bloody stool several minutes later, but has had no bleeding since then. The patient has never had similar symptoms before and reports no fever, nausea, vomiting, hematemesis, abdominal pain, or weight loss. Medical history includes hypertension, for which he takes lisinopril. His most recent colonoscopy was 5 years ago, which revealed diverticulosis and 2 colonic polyps that were removed. The patient is a former smoker and drinks alcohol socially. Temperature is 37.2 C (99 F), blood pressure is 116/70 mm Hg without orthostatic changes, and pulse is 94/min. Lungs are clear to auscultation, and heart sounds are normal. The abdomen is nondistended, soft, and nontender without masses or hepatosplenomegaly. Rectal examination reveals bright red blood in the rectal vault and internal hemorrhoids, but no palpable mass or tenderness. Which of the following is the most likely source of this patient's rectal bleeding?

Question

A 65-year-old man comes to the emergency department after 2 episodes of bloody bowel movements.  The patient felt well until approximately 3 hours ago when he had a sudden urge to defecate, followed by passage of a large amount of bright red blood.  He had another small amount of bloody stool several minutes later, but has had no bleeding since then.  The patient has never had similar symptoms before and reports no fever, nausea, vomiting, hematemesis, abdominal pain, or weight loss.  Medical history includes hypertension, for which he takes lisinopril.  His most recent colonoscopy was 5 years ago, which revealed diverticulosis and 2 colonic polyps that were removed.  The patient is a former smoker and drinks alcohol socially.  Temperature is 37.2 C (99 F), blood pressure is 116/70 mm Hg without orthostatic changes, and pulse is 94/min.  Lungs are clear to auscultation, and heart sounds are normal.  The abdomen is nondistended, soft, and nontender without masses or hepatosplenomegaly.  Rectal examination reveals bright red blood in the rectal vault and internal hemorrhoids, but no palpable mass or tenderness.  Which of the following is the most likely source of this patient's rectal bleeding?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c152_76a7_8f63_f5a00871ef55_MD0005_00 This patient with 2 episodes of hematochezia and a history of diverticulosis most likely has diverticular bleeding (DB). Colonic diverticulosis results from outpouching of the colon wall at points of weakness where the vasa recta penetrate the circular muscle layer of the colon. As the mucosa and submucosa herniate through the muscular layer, the penetrating artery that predisposed the diverticula becomes increasingly exposed. The exposed artery is no longer protected by the muscular layer, and DB occurs as the artery is injured from erosion or trauma to the mucosal layer. DB usually manifests as painless hematochezia; however, right-sided DB, which is more common than left-sided, may sometimes present with melena. Other common symptoms include bloating and cramping due to the cathartic effect of blood in the gastrointestinal tract. The bleeding is usually self-limited, but management involves fluid resuscitation and, if necessary, transfusion of blood products. Patients should undergo colonoscopy for cauterization or tamponade of visible bleeding vessels, although angiography with embolization is an alternate management strategy. Surgical management should be considered for patients who continue to bleed despite endoscopic and angiographic management. (Choice A) Colonic angiodysplasia (arteriovenous malformation) describes the development of dilated, tortuous submucosal vessels and is a common cause of hematochezia. However, DB is more likely in this patient with a history of diverticulosis and no predisposing risk factors for colonic angiodysplasia (eg, end-stage kidney disease, von Willebrand disease, aortic stenosis). (Choice B) Dilation of the submucosal venous plexus occurs in both internal and external hemorrhoids. Although this patient has evidence of internal hemorrhoids, hemorrhoidal bleeding is usually characterized by small-volume bright red blood that covers the stool. Patients may also report mucus, perianal itching, and mild fecal leakage. (Choice D) Diverticulitis results when a colonic diverticulum becomes inflamed and perforates. Microperforation can result in uncomplicated diverticulitis whereas macroperforation can result in complications such as abscess formation or fistulization into adjacent organs (eg, urinary bladder). Patients commonly present with fever, abdominal pain, nausea, and vomiting, but hematochezia is rare. (Choice E) Colorectal cancer may ulcerate and present with hematochezia or melena, but patients also frequently report abdominal pain, weight loss, and a progressive change in bowel habits. Educational objective: Colonic diverticulosis, which commonly presents with painless hematochezia, results from outpouching of the colon walls at points of weakness where the vasa recta penetrate the circular muscle layer of the colon. Bleeding occurs as the exposed artery is injured, usually from erosion or trauma. References: Diverticular bleeding. (http://www.ncbi.nlm.nih.gov/pubmed/19873964) Endoscopic management of diverticular bleeding. (http://www.ncbi.nlm.nih.gov/pubmed/25548554)

A 65-Year-Old Man Comes to the Emergency Department After 2