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A 43-year-old woman presented with acute lower intestinal bleeding requiring blood transfusion. Multiple initial investigations did not reveal the cause of the bleeding. Colonoscopy performed 2 days later showed features suggestive of ischemic colitis. On detailed history, the patient admitted to using amphetamines, and her urine drug screen was positive for them. She was managed conservatively and advised not to use amphetamines again. She did not have any recurrence on 2-year follow-up.
Ischemic colitis is a relatively infrequent cause of acute lower gastrointestinal bleeding (6%–18% of cases) (1, 2). Among cases of ischemic colitis, a drug-induced etiology is an uncommon cause. Amphetamines, both prescription drugs and drugs of abuse, have been known to cause ischemic colitis (3, 4). Patients tend not to divulge their use of amphetamines. Identification of the root cause and avoidance of the use of the incriminating agents can be curative in such cases.
A 43-year-old woman with no previous significant medical illness except for hypothyroidism presented with sudden onset of lower abdominal pain and bloody diarrhea. Her hemoglobin level was 6.8 g/dL, and a blood transfusion was given. She denied prior gastrointestinal bleeding or known liver disease. A computed tomography scan of the abdomen was normal except for mesenteric fat stranding. She had no risk factors for atherosclerotic vascular disease. A workup for lupus and thrombophiliaz—including tests for antinuclear antibody, anti-ds DNA, protein C, protein S, anti-thrombin III, anti-phospholipid antibody, and prothrombin gene mutation—was negative. Mesenteric Doppler showed normal flow in the mesenteric vessels. A colonoscopy, performed 2 days after the presentation, showed mucosal bleeds, hemorrhagic nodules, inflammation, and other features in the sigmoid colon suggestive of ischemic colitis (Figure). Microscopic examination of the colonic mucosa also confirmed the diagnosis of acute mesenteric ischemia. At this point, she admitted using amphetamines. She had quit this habit but relapsed 2 days prior to admission and started snorting amphetamines again. A urine drug screen was positive for amphetamines. She was advised to avoid the use of amphetamines and did not have any events on follow-up.
Ischemic colitis, as the name suggests, develops from hypoperfusion of the colon. It might be the result of occlusive vascular disease or transient low-flow states, especially when the mesenteric vessels are diseased. Mesenteric vascular disease is a manifestation of atherosclerosis, and the risk factors are similar. The watershed areas of the colon such as the splenic flexure and rectosigmoid region are commonly affected with ischemic colitis. Ischemic colitis usually occurs in patients who are older than 60 years of age (5). The most common presenting symptom is abdominal pain. Other symptoms include abdominal distention, shock, sepsis, hematochezia, and diarrhea. Other causes of ischemic colitis include vasculitis, embolism, hypercoagulable states, colonic obstruction, and drugs (6). Ischemic colitis in younger patients should prompt the search for such causes. Exclusion of these causes is prudent before attributing ischemic colitis to drugs.
Dietary supplementation with phentermine (an amphetamine-derived sympathomimetic) can be associated with ischemic colitis (3). Amphetamine-induced systemic effects are believed to be due to release of vasoactive amines. The central effects are caused by dopamine and the peripheral effects are due to norepinephrine. Intestinal ischemia may be due to splanchnic vasoconstriction but can also be due to necrotizing angitis (7, 8).
Colonoscopy and imaging modalities may be helpful in diagnosis. Mucosal bleeds, hemorrhagic nodules, edema, longitudinal ulcers, and gangrene may be observed on colonoscopy. However, none of these findings except for gangrene is specific for ischemic colitis (9). Thickening of the bowel wall may be observed with computed tomography and ultrasound.
Supportive management is generally advised in the absence of colonic perforation of gangrene. Bowel rest, intravenous fluids, antibiotics, and optimization of blood pressure and cardiac output are desirable. Avoidance of drugs that precipitated ischemic colitis is of paramount importance in drug-induced ischemic colitis. Early identification and management of complications, like gangrene of colon and peritonitis, is prudent. About 1 in 5 patients with ischemic colitis require surgery due to such complications. Nonviable areas of bowel are resected during surgery. Patients with extensive areas of infarcted bowel have a high mortality rate.