A 72-year-old woman comes to the emergency department due to bloody bowel movements. One hour ago, the patient had a sudden urge to defecate and passed a large amount of bright red blood mixed with stool. Several minutes later, she had another episode with a small amount of blood. The patient reports no nausea, vomiting, abdominal pain, diarrhea, or fever and never had such symptoms before. She is hospitalized but has no further bleeding. Physical examination, including a digital rectal examination, is unremarkable. A colonoscopy performed after bowel preparation reveals the findings in the exhibit. There are no other abnormalities. Which of following is the most likely source of this patient's bleeding?

Question

A 72-year-old woman comes to the emergency department due to bloody bowel movements.  One hour ago, the patient had a sudden urge to defecate and passed a large amount of bright red blood mixed with stool.  Several minutes later, she had another episode with a small amount of blood.  The patient reports no nausea, vomiting, abdominal pain, diarrhea, or fever and never had such symptoms before.  She is hospitalized but has no further bleeding.  Physical examination, including a digital rectal examination, is unremarkable.  A colonoscopy performed after bowel preparation reveals the findings in the exhibit.  There are no other abnormalities.  Which of following is the most likely source of this patient's bleeding?

Quizplus · Accepted Answer

11ec160b_3941_3aa1_9249_ab77eaa92e61_MD0001_00 This patient with hematochezia had a colonoscopy revealing multiple outpouchings of the colonic mucosa, consistent with colonic diverticulosis. The incidence of diverticulosis increases with age and is seen typically in patients age >60. Risk factors include low-fiber, high-fat diet, obesity, and physical inactivity. Diverticula tend to form in areas where the intraluminal colon wall lacks structural integrity. Typically, these weak points are located where the vasa recta (terminal vessels derived from the superior and inferior mesenteric arteries) penetrate through the smooth muscular layer of the colon. As the diverticula enlarge, the vessels are exposed to chronic injury, leading to thinning of the vascular media. Ultimately, the weakened vessels can ulcerate and rupture, leading to intraluminal hemorrhage and painless hematochezia that is often self-limited but can occasionally result in hemodynamic instability. Management includes patient resuscitation (eg, intravenous fluids) and colonoscopy, which can diagnose diverticulosis and may identify and treat the source of any active bleeding; angiography or surgery may be required for persistent bleeding. (Choice A) Angiodysplasias are abnormal arteriovenous channels that form from ectatic, thin-walled vessels within the gastrointestinal tract. Although they can also cause painless hematochezia, they are identified on colonoscopy as flat, red lesions with a fern-like or arborized appearance. (Choice B) Diffuse, continuous mucosal inflammation and erosion extending from the rectum and into the proximal colon are consistent with ulcerative colitis (UC) and typically grossly visible on endoscopy. Although UC also causes hematochezia, it is typically associated with diarrhea, progressive abdominal pain, tenesmus, and fevers. (Choice C) Hemorrhoids are characterized by dilation and tortuosity of the rectal venous plexuses. These appear as a purplish or bluish bulge at the anorectum and are identified easily on physical examination or during colonoscopy. (Choice E) Colorectal adenocarcinoma, which arises typically from colonic polyps, can also cause hematochezia due to mucosal sloughing but is usually identified during a colonoscopy as an ulcerated polypoid mass. Patients also often have a history of unexplained weight loss, fatigue, or abnormal stool caliber (eg, pencil-thin stool). Educational objective: Colonic diverticula form at weak points in the colon wall, typically in areas where the vasa recta penetrate through the smooth muscle. As diverticula enlarge, the vasa recta are exposed and become vulnerable to chronic injury, which can lead to intraluminal hemorrhage and painless hematochezia.

A 72-Year-Old Woman Comes to the Emergency Department Due to Bloody