A case of cerebral infarction in association with free protein S deficiency and oral contraceptive use.

The purpose of this article is to describe protein S deficiency as a cause of cerebral infarction in the young adult. We report a 27-year-old previously healthy woman with a primary free protein S deficiency, who developed a left temporoparietal infarction. Protein S is a naturally occurring vitamin K-dependent protein which, in conjunction with active protein C, inhibits the clotting cascade. Protein S deficiency is known to be of clinical significance in patients with deep venous thrombosis or pulmonary emboli and in these patients, treatment is long-term anticoagulation. Protein S deficiency has been found to be associated with cerebrovascular occlusion and may possibly warrant long-term anticoagulation in these patients as well. Measurement of total and free protein S levels should be part of the evaluation for any young adult who has had a stroke.