A 64-year-old man comes to the emergency department due to diarrhea and intermittent abdominal cramps for the last 6 weeks. He has had 4 or 5 bowel movements every day, and the stool contains blood and mucus. He also reports poor appetite and fatigue and has lost 5.9 kg (13 lb) over this period. The patient has intermittent right knee swelling and tenderness that responds to ibuprofen. He has not taken any antibiotics recently. He has no other medical problems. The patient last saw a physician 2 years ago, and his last colonoscopy 4 years ago was normal. Family history is positive for colon cancer in his mother. Temperature is 37.3 C (99.1 F), blood pressure is 142/84 mm Hg, pulse is 98/min, and respirations are 16/min. Physical examination shows tenderness in the left lower quadrant without rebound or guarding. Digital rectal examination is positive for blood. Laboratory results are as follows: Flexible sigmoidoscopy reveals erythematous friable mucosa extending from the rectum to the sigmoid colon. Small shallow ulcers are also seen. Which of the following is the most likely cause of this patient's current condition?

Question

A 64-year-old man comes to the emergency department due to diarrhea and intermittent abdominal cramps for the last 6 weeks.  He has had 4 or 5 bowel movements every day, and the stool contains blood and mucus.  He also reports poor appetite and fatigue and has lost 5.9 kg (13 lb) over this period.  The patient has intermittent right knee swelling and tenderness that responds to ibuprofen.  He has not taken any antibiotics recently.  He has no other medical problems.  The patient last saw a physician 2 years ago, and his last colonoscopy 4 years ago was normal.  Family history is positive for colon cancer in his mother.  Temperature is 37.3 C (99.1 F), blood pressure is 142/84 mm Hg, pulse is 98/min, and respirations are 16/min.  Physical examination shows tenderness in the left lower quadrant without rebound or guarding.  Digital rectal examination is positive for blood.  Laboratory results are as follows:  Flexible sigmoidoscopy reveals erythematous friable mucosa extending from the rectum to the sigmoid colon.  Small shallow ulcers are also seen.  Which of the following is the most likely cause of this patient's current condition?

Quizplus · Accepted Answer

11ec25c8_d3f3_a618_bc81_d3ed5ac47be8_MD0003_00 This patient's symptoms are concerning for ulcerative colitis (UC). Similar to Crohn disease (CD), most patients first develop UC at age 15-40; however, there appears to be a bimodal distribution, with a second peak at age 50-80. UC is characterized by chronic idiopathic inflammation of the colon and rectum with intermittent exacerbations. Patients commonly have abdominal pain, bloody diarrhea, tenesmus, fecal incontinence, and, in more severe cases, weight loss. UC may be complicated by toxic megacolon. The most common extraintestinal manifestations include arthritis (seen in this patient), uveitis, episcleritis, erythema nodosum, and primary sclerosing cholangitis. Laboratory findings can include leukocytosis, iron deficiency anemia, reactive thrombocytosis, and elevated inflammatory markers (eg, erythrocyte sedimentation rate [ESR]). Endoscopy may demonstrate erythematous and friable mucosa with ulcers, as seen in this patient. Exudates, edema, and spontaneous bleeding may also be evident. The lesions are usually continuous and circumferential (unlike in CD). Biopsy shows inflammation limited to the mucosa and submucosa (compared to transmural inflammation in CD) with crypt abscesses and crypt distortion. (Choice A) Amebic colitis also commonly presents with bloody diarrhea, abdominal pain, and elevated inflammatory markers but is typically less acute. In addition, endoscopy commonly shows skip lesions as opposed to contiguous areas of inflammation and ulcers. (Choice B) Clostridium difficile infection is classically associated with pseudomembranes on endoscopy. It usually causes a pancolitis, presents with watery diarrhea, and occurs most commonly in patients with a history of recent antibiotic use. (Choice C) Although this patient's age, weight loss, and anemia are concerning for colon cancer, his recent negative colonoscopy, lack of masses on endoscopy, and elevated ESR make this much less likely. Moreover, diarrhea is not a common presentation of colon cancer. (Choices D and E) Patients with chronic colonic ischemia or small-vessel vasculitis can also present with bloody diarrhea and weight loss and may be initially misdiagnosed with UC. However, the significant elevation in ESR and the involvement of the rectum, which has a dual blood supply, make ischemia due to atherosclerosis less likely. Moreover, this patient's lack of other findings of small-vessel inflammation (eg, skin, pulmonary, or renal involvement) reduces the likelihood of vasculitis. Educational objective: There appears to be a bimodal distribution of ulcerative colitis with a second peak at age 50-80. Patients commonly experience abdominal pain, bloody diarrhea, tenesmus, and fecal incontinence. Endoscopy demonstrates continuous involvement with erythematous and friable mucosa and ulcers. References: Ulcerative colitis. (http://www.ncbi.nlm.nih.gov/pubmed/23939448)

A 64-Year-Old Man Comes to the Emergency Department Due to Diarrhea