Case Presentation: A 44-year-old African-American male with past medical history of hypertension, asthma and obesity, presented to the emergency room with acute onset, constant, severe lower abdominal pain of two days duration which was throbbing and aching in quality without any radiation. He also endorsed nausea & loose stools. Of note, his hypertension was newly diagnosed 3 weeks before, and he was started on lisinopril at that time. The only other medication he had was an albuterol rescue inhaler. There were no known allergies to any medication. Physical examination revealed normal vital signs as well as a soft, protuberant abdomen with tenderness in lower quadrants and hypoactive bowel sounds. McBurney’s sign was absent. Pertinent labs include slightly elevated creatinine of 1.4 mg/dL and normal white blood cell counts. Computed tomography (CT) scan of the abdomen and pelvis revealed thickened, inflamed loops of a long segment of the jejunum, with interloop fluid, areas of marked submucosal edema surrounded by enhancing mucosa and serosa (‘doughnut sign’), and mesenteric engorgement. Additional investigations showed normal C1 esterase and complement C4 levels, ruling out hereditary angioedema. He was clinically diagnosed with lisinopril-induced mesenteric angioedema and lisinopril was discontinued. He was managed supportively with bowel rest for a day, intravenous fluids, and H2 blockers. He improved clinically and his diet was progressively advanced as tolerated. He was discharged to his home after 48 hours.
Discussion: Angiotensin Converting Enzyme (ACE) inhibitors are widely used in clinical practice for management of hypertension, heart failure and kidney disease. They are generally well tolerated. Among the few idiosyncratic side effects of ACE inhibitors, angioedema is relatively rare and potentially fatal with an estimated incidence of 0.1 to 0.7 % among recipients. Visceral angioedema is even rarer, with only a handful of cases reported in the literature. It can present with symptoms such as abdominal pain, diarrhea, vomiting, anorexia, and ascites, the differential diagnosis for which are numerous. In this case, the onset of symptoms were about three weeks after initiating lisinopril, which made the diagnosis relatively obvious. This is not always the case, as the angioedema can present within 72 hours of starting ACE inhibitor therapy, or after weeks to years of therapy. In such cases diagnosis depends on clinical suspicion in conjunction with helpful CT abdomen findings such as ‘doughnut sign’ as seen in this case, thickened mucosal folds with a ‘stacked coin’ appearance and mesenteric edema.
Conclusions: The rarity, non-specificity of presentation, varied chronology, and absence of any confirmatory testing makes the diagnosis of ACE inhibitor induced visceral angioedema an elusive one, thus leading to unwarranted invasive procedures; this case illustrates the importance of a thorough history including a complete medication reconciliation.