Angioedema from angiotensin-converting enzyme (ACE) inhibitor treated with complement 1 (C1) inhibitor concentrate

Background: Up to seven in every 1000 patients experience angioedema from angiotensin-converting enzyme (ACE) inhibitors, even after many years of use. In 2003, every 20th Norwegian used an ACE inhibitor. Case report: A 61-year-old woman with chronic obstructive pulmonary disease and a past acute myocardial infarction had used 7.5 mg of ramipril daily for the past 7 years. She also used acetylsalicylic acid, simvastatin, theophylline and salmeterol. One night she woke up with edema of the tongue. On hospital arrival, 250 mg of hydrocortisone and 5 mg of dexchlorpheniramine were given intravenously (i.v.) and 0.3 mg of epinephrine was given subcutaneously (s.c.). The edema of the tongue progressed over the next 8 h and made the tongue protrude. Fiberscopy revealed glassy edema of the arytenoids. Inspiratory stridor was heard and the patient could not speak. She became increasingly uneasy and restless. Berinert (R) complement 1 (C1) inhibitor concentrate (1500 units) was administered i.v. Over the following 20 min, stridor gradually subsided, the patient calmed and she was able to talk. Discussion: ACE inhibitor-provoked angioedema shares many clinical features with hereditary angioedema (HAE), including a limited effect of steroids, antihistamines and epinephrine. HAE, caused by excess bradykinin formation as a result of C1 inhibitor deficiency, usually has its laryngeal edema effectively reversed by C1 inhibitor in less than 0.5 h. Although patients experiencing ACE inhibitor-provoked angioedema have normal C1 inhibitor values, as in our patient, excess bradykinin is probably important as ACE breaks down bradykinin. It is unknown why ACE inhibitor-provoked angioedema appears in some and sometimes after many years of use. Conclusion: We believe that C1 inhibitor was effective in reversing the ACE inhibitor-induced angioedema in our patient.