eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2019-11-12 8 1 8 10 10.12691/ajmcr-8-1-2 AJMCR2020812 article Tariq Sharman tysharman@yahoo.com 1 Jeffrey Song 1 Misam Zawit 1 Una Ijeoma-Nchinda 1 Department of Medicine, Heritage College of Osteopathic Medicine, Southern Ohio Medical Center, Ohio University, Portsmouth, Ohio, USA Angiotensin-converting enzyme (ACE) inhibitors are amongst the commonest prescribed medications in the United States and considered to be the leading causes of drug induced angioedema. High bradykinin levels stimulate vasodilation and increased vascular permeability of the post-capillary venules and allow for plasma extravasation into the submucosal tissue, leading to angioedema. Usually, the angioedema occurs within the first week of exposure to therapy, but cases occurring after years of stable ACE inhibitor usage are not uncommon. Here, we present a 43-year-old Caucasian female who developed acute respiratory failure requiring mechanical ventilation secondary to ACEi-induced angioedema after five years of Lisinopril usage. This case will help to increase physicians’ awareness that this potentially fatal complication can still occur after years of ACE inhibitor usage. http://pubs.sciepub.com/ajmcr/8/1/2/ajmcr-8-1-2.pdf Angioedema Angiotensin converting enzyme inhibitor Bradykinin des-Arg9-BK Complement C4 substance P ACE