ACE Inhibitor Induced Isolated Angioedema of the Small Bowel: A Rare Complication of a Common Medication

Angioedema is a subcutaneous or submucosal tissue swelling due to capillary leakage and transudation of fluid into the interstitial tissue. It can be localized or generalized as part of a widespread reaction known as anaphylaxis. Millions of people in United States and all over the world receive ACEI antihypertensive therapy. ACEI is known to cause angioedema with an incidence of 0.7 percent. We present a case of 40-year-old female who was started on lisinopril three days prior to presentation for newly diagnosed hypertension. She presented with nonspecific severe abdominal pain, nausea, and vomiting. She denied having difficulty breathing or swelling anywhere in the body. On exam, she did not have facial, lip, tongue, or throat swelling. Her abdomen was tender without guarding or rigidity. Laboratory examination was unrevealing except for mild leukocytosis. Computed tomography scan (CT scan) of the abdomen with oral and IV contrast revealed a moderate amount of ascites with diffuse wall thickening, hyperenhancement, and mucosal edema of the entire small bowel. In the absence of any other pathology, matching history, and imaging findings highly suggestive of angioedema, she was diagnosed with isolated small bowel angioedema as a result of ACEI therapy. She was managed conservatively, and lisinopril was discontinued. A week later on follow-up, all her symptoms had resolved, and repeat CT scan showed resolution of all findings.