ABSTRACT
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.
PIP: A 27-year-old woman suffered from a sudden onset of slight paralysis of the right side of her body and the inability to express herself by speech, writing, or signs. She was admitted to the National Rehabilitation Hospital in Washington, D.C., in the US. 6 months prior to these events, she had been in a motor vehicle accident and had since experienced headaches and generalized musculoskeletal pain. The only drug she took was an oral contraceptive (OC), which she took irregularly. Health workers could not arouse her upon admission. Clinical examination revealed symptoms consistent with a left hemispheric stroke. Cerebral computed tomography and magnetic resonance imaging revealed a left temporoparietal infarct. Her free protein S was only 27% on admission and 14% 11 days after admission (normal range, 55-125%). Over the next 72 hours, her physical condition deteriorated, entailing focal motor seizures, right Babinski's sign, loss of pain reflex response on her right side, and complete paralysis of the right side of her body. The left middle cerebral artery appeared to be constricted, which physicians first believed was caused by vasculitis but later found was the result of emboli. The patient developed right femoral vein deep thrombosis. The physicians treated her initially with heparin and followed with warfarin therapy. Nevertheless, embolus. Health workers placed a filter in her inferior vena cava and continued warfarin therapy. She did not experience any more thrombotic or embolic episodes during the rest of her hospital stay. OCs reduce circulating levels of free protein S which, along with activated protein C, inhibits clotting. OCs likely reduced her already existing low levels of free protein S. Deficiency of free protein S was likely responsible for the cerebral infarction and her thrombotic and embolic episodes.
