Critical Care Medicine-Gastrointestinal, Nutrition and Genitourinary Disorders>>>>>Large Intestine
Question 5#

A 55-year-old female is admitted to the surgical intensive care unit with severe abdominal pain, nausea, vomiting, and diarrhea for the last 3 days. Her vitals at arrival are as follows: heart rate 122 bpm, blood pressure 100/50 mm Hg, temperature 102°F. On examination her abdomen is diffusely tender with voluntary guarding. Laboratory test results are notable for a leukocytosis of 18,000 cells/mL and hypokalemia. A thorough medical history is significant for a recent diagnosis of ulcerative colitis treated with sulfasalazine and a recent urinary tract infection of which she completed a 7-day course of ciprofloxacin. A CT of the abdomen and pelvis is performed, which demonstrates a significantly dilated colon up to 6 cm in diameter and diffuse colonic wall thickening with patent vasculature.

What additional testing is required before full medical management can be initiated. 

A. CT angiography of the mesenteric vessels
B. Colonoscopy with biopsies
C. Clostridium difficile stool test
D. Serum CMV test
E. Barium enema

Correct Answer is C

Comment:

Correct Answer: C

This patient has findings concerning for toxic megacolon based on the following criteria: radiologic evidence of colonic distension, plus at least three of the following: fever >38°C, heart rate >120 bpm, neutrophilic leukocytosis >10,500 or anemia; plus at least one of the following: dehydration, altered sensorium, electrolyte disturbances, hypotension. In contrast to ulcerative colitis where inflammation is limited to the mucosa, toxic megacolon is characterized by extension of severe of inflammation to the smooth muscle layer, which is thought to lead to the colonic distension. Although toxic megacolon is most commonly recognized as a complication of inflammatory bowel disease (IBD), it can also occur with infectious and ischemic colitides. Toxic megacolon most commonly occurs during the first several months after diagnosis of IBD and not infrequently is the first manifestation of the disease. IBD is also a risk factor for C. difficile colitis and so is her recent antibiotic exposure. Medical treatment for IBD versus C. difficile differs in the choice of antibiotics and the use of corticosteroids. Steroids have not been found to increase the risk of colonic perforation; however, they will significantly suppress the immune systems response to infectious colitides such as cytomegalovirus (CMV), amebic, and bacterial (Shigella, Salmonella, Campylobacter, and C. difficile). This patient has no prior history of immunosuppression, and thus CMV is unlikely and the diagnosis of CMV colitis often requires endoscopic biopsies, which is too risky in toxic megacolon. Barium enemas to rule out distal obstruction are also high risk for perforation and should be avoided if possible.

References:

  1. Gan SI, Beck PL. A new look at toxic megacolon: an update and review of incidence, etiology, pathogenesis and management. Am J Gastroenterol. 2003;98:2363.
  2. Dieterich DT, Rahmin M. Cytomegalovirus colitis in AIDS: presentation in 44 patients and a review of the literature. J Acquir Immune Defic Syndr. 1991;4(suppl 1):S29.