A 70-year-old woman comes to the emergency department due to abdominal pain and bloody diarrhea. Last night, the patient experienced mild cramping with abdominal pain and an urgent desire to defecate, but when she went to the bathroom, she did not have a bowel movement. The patient attributed her symptoms to the spicy food she had for lunch and took some antacids, but the pain persisted. This morning she had large-volume diarrhea containing bright red blood. She has had no nausea or vomiting and has never had similar symptoms. The patient was found to have diverticulosis during a colonoscopy 2 years ago, so a high-fiber diet was advised. Other medical problems include hypertension, type 2 diabetes mellitus, coronary artery disease, and end-stage renal disease from diabetic nephropathy. She receives intermittent maintenance hemodialysis (most recently yesterday) and has had several occasions of hypotension during dialysis, requiring intravenous fluid replacement. The patient does not use tobacco, alcohol, or illicit drugs. She has taken no antibiotics or nonsteroidal analgesics recently. The patient lives with her husband and has not recently traveled. Temperature is 37.2 C (99 F), blood pressure is 119/81 mm Hg, pulse is 90/min, and respirations are 16/min. The abdomen is mildly distended and soft with moderate left-sided tenderness. There is no rebound tenderness and bowel sounds are decreased. Rectal examination reveals bloody stool but no tenderness or mass. Laboratory results are as follows: Upright abdominal radiography reveals a dilated transverse colon with no free air. Flexible sigmoidoscopy shows mucosal edema. Which of the following is the most likely cause of this patient's current symptoms?

Question

A 70-year-old woman comes to the emergency department due to abdominal pain and bloody diarrhea.  Last night, the patient experienced mild cramping with abdominal pain and an urgent desire to defecate, but when she went to the bathroom, she did not have a bowel movement.  The patient attributed her symptoms to the spicy food she had for lunch and took some antacids, but the pain persisted.  This morning she had large-volume diarrhea containing bright red blood.  She has had no nausea or vomiting and has never had similar symptoms.  The patient was found to have diverticulosis during a colonoscopy 2 years ago, so a high-fiber diet was advised.  Other medical problems include hypertension, type 2 diabetes mellitus, coronary artery disease, and end-stage renal disease from diabetic nephropathy.  She receives intermittent maintenance hemodialysis (most recently yesterday) and has had several occasions of hypotension during dialysis, requiring intravenous fluid replacement.  The patient does not use tobacco, alcohol, or illicit drugs.  She has taken no antibiotics or nonsteroidal analgesics recently.  The patient lives with her husband and has not recently traveled.  Temperature is 37.2 C (99 F), blood pressure is 119/81 mm Hg, pulse is 90/min, and respirations are 16/min.  The abdomen is mildly distended and soft with moderate left-sided tenderness.  There is no rebound tenderness and bowel sounds are decreased.  Rectal examination reveals bloody stool but no tenderness or mass.  Laboratory results are as follows:  Upright abdominal radiography reveals a dilated transverse colon with no free air.  Flexible sigmoidoscopy shows mucosal edema.  Which of the following is the most likely cause of this patient's current symptoms?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c150_f004_8f63_65b90a3c47c4_MD0005_00 This patient has several risk factors for underlying atherosclerosis (eg, hypertension, diabetes mellitus, end-stage renal disease), which increases the risk of developing colonic ischemia (CI). CI most commonly occurs in the setting of nonocclusive disease, when a mismatch between oxygen demand and supply results from diffuse mesenteric atherosclerosis combined with a state of low blood flow (eg, hypovolemia during hemodialysis). The most vulnerable colonic regions are those with limited collateral blood flow (eg, splenic flexure, rectosigmoid junction). Less commonly, occlusive disease can occur due to an embolic event or atherosclerotic plaque rupture. CI frequently presents with acute, crampy abdominal pain and fecal urgency, which may be followed by an episode of bloody diarrhea. In some patients, the presentation can be more chronic than acute. Unlike the pain of mesenteric ischemia of the small bowel, which is typically severe and periumbilical in location, the pain of CI is usually relatively mild and located more peripherally in the abdomen. Leukocytosis and lactic acidosis are common laboratory findings. Radiography may show colonic distension or pneumatosis (gas in the bowel wall), and lower endoscopy can confirm the diagnosis by demonstrating friable, edematous mucosa; erythema; and scattered pale patches. pneumatosis (Choice B) Acute diverticulitis also presents with abdominal pain and leukocytosis; however, patients also frequently report fever, nausea, vomiting, and nonbloody diarrhea. In addition, diverticulitis would not explain this patient's imaging or endoscopy findings. (Choice C) Angiodysplasia is an uncommon cause of gastrointestinal bleeding and is characterized by painless hemorrhage. Risk factors include aortic stenosis, von Willebrand disease, and chronic kidney disease. (Choice D) Pseudomembranous colitis due to Clostridium difficile or Salmonella infection is also commonly associated with diarrhea, abdominal pain, leukocytosis, bowel dilation on imaging, and edematous mucosa on endoscopy. However, diarrhea is typically watery, and although occult blood may be present in the stool, evidence of frank hemorrhage is rare. In addition, this patient's lack of recent travel or antibiotic exposure further decreases this likelihood. (Choice E) Ulcerative colitis commonly presents with the subacute onset of bloody diarrhea, abdominal pain, urgency, tenesmus, and incontinence. In addition to mucosal edema, endoscopy commonly shows loss of vascular markings, exudates, and spontaneous hemorrhage. Educational objective: Colonic ischemia most commonly occurs due to nonocclusive disease in the setting of underlying atherosclerosis and a state of low blood flow. Patients typically have abdominal pain, bloody diarrhea, and fecal urgency as well as leukocytosis, lactic acidosis, and colonic distension or pneumatosis shown on abdominal x-rays. References: Ischemic colitis: clinical practice in diagnosis and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/19109863)

A 70-Year-Old Woman Comes to the Emergency Department Due to Abdominal