ACE inhibitor induced visceral angioedema: an elusive diagnosis

ACE inhibitors are widely used and well-tolerated drugs. Angioedema is a well-known adverse effect, which involves the viscera rarely. This is a case of a 44-year-old African-American man with newly diagnosed hypertension, who presented with lower abdominal pain and diarrhoea. Based on the clinical picture and radiographic findings, lisinopril-induced intestinal angioedema was diagnosed. He recovered with supportive treatment, and the lisinopril was permanently discontinued. The mechanism of angioedema is thought to be the inhibition of ACE-mediated degradation of bradykinin, which is a peptide responsible for vasodilation and increased vascular permeability. While the external angioedema is unmistakable, intestinal angioedema has a relatively non-specific presentation and chronology, often leading to missed diagnosis and unnecessary interventions. Most common symptoms are abdominal pain and diarrhoea. Characteristic radiographic findings include 'doughnut sign' and 'stacked coin' appearance. Treatment is supportive. ACE inhibitors should be discontinued to prevent a recurrence.