Clotting changes in Cushing's syndrome: elevated factor VIII activity.

Thirteen women and 2 men affected by Cushing's syndrome were investigated. The following parameters were used: plasma and urinary cortisol levels, factor VIII assay (antigen, activity and von Willebrand factor) together with other coagulative assays. Samples were taken before surgery or before medical and/or radiation therapy and every 30-50 days after treatment and continued for 11 months. Cortisol and factor VIII were increased before treatment and decreased slowly after treatment to become normal in 3-4 months. Other clotting tests did not show any significant changes. High plasma cortisol levels seem to stimulate the production of factor VIII. Patients with Cushing's syndrome often exhibit thromboembolic complications after surgery. The clotting abnormalities responsible for such complications may be due to increased factor VIII activities.