Lisinopril-Induced Small Bowel Angioedema: An Unusual Cause of Severe Abdominal Pain

BACKGROUND Angiotensin-converting enzyme inhibitors (ACE-I) are one of the most frequently prescribed classes of medications with the rare adverse effect of angioedema, and isolated small bowel angioedema is a small subset of these cases. Isolated angioedema of the small bowel is a rare adverse effect of this commonly prescribed medication, and it mimics, symptomatically and radiographically, several other illnesses and is often misdiagnosed. While ACE-I are thought to be safe, the risk of angioedema is approximately 0.7%. Isolated small bowel angioedema is often not diagnosed in a timely manner, and misdiagnosis leads to significant morbidity in afflicted patients. CASE REPORT We present the case of a 63-year-old woman with angioedema of the small bowel causing abdominal pain, nausea, vomiting, and diarrhea. Computed tomography demonstrated small bowel edema and ascites. The patient had been taking lisinopril for 7 years prior to presentation and had previously been seen by multiple physicians for abdominal pain. A diagnosis of ACE-I-induced small bowel angioedema was made and lisinopril therapy was immediately stopped. Her symptoms improved with cessation of lisinopril, and follow-up imaging showed resolution of the angioedema 3 months later. CONCLUSIONS The course of ACE-I-induced angioedema is unpredictable and often overlooked as a cause of abdominal pain. It commonly presents soon after starting ACE-I therapy, but can present years after therapy initiation, as in this case. Significant morbidity, including unnecessary exploratory laparotomy, is associated with misdiagnosis of ACE-I-induced angioedema of the small bowel. Prompt recognition and cessation of the offending drug is crucial but often delayed.