Hereditary angioedema presenting in late middle age after angiotensin-converting enzyme inhibitor treatment.

Background: Angioedema due to Cl esterase inhibitor (CI-INH) deficiency may be hereditary (HAE), commonly first occurring in childhood, or acquired (AAE), with onset usually in middle age. Type I HAE exhibits low levels of functionally normal C1-INH. Dysfunctional Cl-INH typifies type II HAE. Patients with type I AAE have low levels of Cl-INH, Clq complement, and C4 complement. In type II AAE, there is immune blockade of C1-INH.

Objective: To describe a man who first presented at the age of 52 years with type I HAE triggered by the administration of an angiotensin-converting enzyme (ACE) inhibitor.

Methods: The patient had C1-INH levels, a complement profile, and a lack of underlying co-pathology that led to the diagnosis of type I HAE triggered by the administration of an ACE inhibitor.

Results: The patient presented with life-threatening angioedema. His C4 complement and Cl-INH serum levels were below the reference ranges, and his C3 complement, total hemolytic complement assay, and Clq complement levels remained within the reference ranges. During the 10 years between his initial episode of angioedema and the second, he had not developed any secondary medical conditions, and he had been taking the ACE inhibitor lisinopril for 7 years.

Conclusion: Physicians must remain aware of the possibility of unmasking HAE in the adult and geriatric population with the common use of ACE inhibitors for the treatment of hypertension, cardiovascular diseases, and metabolic diseases.