Ischemic Colitis of the Ascending Colon: A Diagnostic and Management Conundrum

Military Medicine, Mar 2008 by Lucha, Paul A Jr

ABSTRACT Ischemic colitis is the most common form of intestinal ischemia. It most commonly involves the left side of the colon presenting with acute onset of abdominal pain followed by bloody diarrhea. Involvement of only the right or ascending colon is an infrequent occurrence. Because this problem is less recognized than its counterpart involving the left colon, the correct diagnosis and management may not be readily considered. We present a case of ischemic colitis presenting as a distal small bowel obstruction with emphasis on evaluation and management of this unusual clinical problem.

CASE REPORT

An 81-year-old male presented through the emergency department witii diffuse abdominal pain, nausea, emesis, and distal small bowel obstruction on plain abdominal films. His initial evaluation included an abdominal computed tomography (CT) scan which revealed inflammatory changes of the ascending colon, a questionable mass, and partial colonic obstruction (Fig. 1). He was placed on empiric antibiotics for possible perforated colon cancer or, less likely, complicated diverticular disease when this management failed; he was slowly bowel prepped for colonoscopy to evaluate for a possible near-obstructing cecal mass. Colonoscopy revealed an exophytic inflamed right colonic mucosa with marked luminal narrowing which could not be traversed and was responsible for the obstruction seen on plain abdominal radiography. Biopsies were not taken as the area could not be traversed and the accessible area was felt to not necessarily be representative of the pathologic process. Right hemicolectomy was performed and final pathology revealed the absence of malignancy and ischemic colitis without evidence of emboli or vasculitis (Fig. 2).

DISCUSSION

Ischemic colitis usually is located in the "watershed" areas of the colon: splenic flexure (Griffith's point) and rectosigmoid junction (Sudeck's point).1,2 In one series, 80% of the patients were female and the average age was 71 years; however, most report the average age at approximately 65 years and 66% female.1,3-5 It presents often with acute onset of abdominal pain (90% of cases) followed by diarrhea (50% of cases) and bleeding (40% of cases).1,2 In the elderly and in patients witii pre-existing coronary or peripheral vascular disease, ischemic colitis classically results as a consequence of intrinsic small vessel disease in the setting of cardiovascular stress. Patients with isolated right colon ischemia most frequently have coronary artery disease as a coexisting complicating illness and may have mortality rates of over 22%.6 In younger patients, consider other etiologies such as collagen vascular disease, hypercoagulable states, medications (oral contraceptives and nonsteroidal anti-inflammatory drugs), toxins (cocaine), long-distance running, and iatrogenics (vascular surgery and colonoscopy). Segmental right-sided colitis may be a consequence of superior mesenteric artery disease (acute mesenteric ischemia) and has been reported to carry a worse prognosis.1,2,4-6 Transient spontaneous ischemic colitis was initially described by Boley et al.7 in the 1960s and has no other demonstrable etiology (normal vascular anatomy, no predisposing medical illnesses) and may range from severe ischemia with necrosis to mild self-limiting forms. Obstruction is a rare complication of acute ischemic colitis. The vast majority of patients make a full recovery with supportive care alone. Some reports have suggested that those patients with isolated right colon ischemia will require operative intervention in over 50% of cases, are more frequently associated with dialysis, and have a higher mortality rate.6 In patients presenting with necrosis or perforation, a reported mortality of over 60% can be expected.2,4,6-8 The evaluation of ischemic colitis will frequently involve CT, contrast enema, or colonoscopy. Angiography should be reserved for tiiose patients with localized right-sided CT scan findings suggesting early acute mesenteric ischemia involving the superior mesenteric artery.1,2,9 This patient underwent colonoscopy and resection as mere was concern that an underlying malignancy was present, and with his obstructive symptoms precluding further evaluation.

SUMMARY

Transient ischemic colitis involving the ascending colon is a rare phenomenon.6,10 Because the diagnosis may be easily overlooked, a high index of suspicion and colonoscopy are important in recognizing the condition early when nonoperative care is most effective. Evaluation for etiology should be based primarily on the findings noted on CT, angiography, and endoscopy which may lead to investigations for hypercoagulable states or embolic sources.

REFERENCES

1. Beck DE (editor): Handbook of Colorectal Surgery, Ed 2, pp 489-94. St. Louis, MO, Marcel Dekker, 2003.

2. Green BT, Tendier DA: Ischemic colitis: a clinical review. South Med J 2005; 98: 217-22.

3. Arnott ID, Ghosh S, Ferguseon A: The spectrum of ischaemic colitis. Eur J Gastroenterol Hepatol 1999; 11: 295-303.