Giant cell arteritis in a patient with acute aortic insufficiency with thyrotoxicosis.

Acute aortic insufficiency in the setting of thyrotoxicosis can mask the presentation of vasculitis. We report a case of a 38-year-old woman with a 22 weeks gestation pregnancy who was known to be hyperthyroid for 4 months prior to conception. She presented with thyrotoxicosis and acute respiratory failure. Echocardiogram revealed severe acute aortic regurgitant flow. Following medical treatment for aortic insufficiency and thyrotoxicosis, the patient underwent ascending aorta replacement with aortic valve repair. Pathological exam revealed giant cell arteritis. Both giant cell arteritis and thyrotoxicosis share a common major histocompatibility antigen which may facilitate concomitant disease presentation. Following immunosuppression for giant cell arteritis, valve repair, and treatment for thyrotoxicosis, the patient made a complete recovery. A rise in human chorionic gonadotropin (HCG) during the first trimester of pregnancy is known to have a stimulatory effect on the thyroid gland and may result in hyperthyroidism. Although HCG may have exacerbated the existing hyperthyroidism, in this case it was not causal, as the diagnosis preceded her pregnancy by several months. Diagnosis of vasculitis may be overshadowed by the presence of thyrotoxicosis. Significant vascular compromise in the setting of thyrotoxicosis must prompt an evaluation for vasculitis. This may prevent unnecessary surgery with attendant morbidity and mortality.