Isolated Protein S Deficiency Leading to Cerebral Venous Sinus Thrombophlebitis in Young Male

Protein S is a potent anticoagulant that downregulates thrombin formation and is a vitamin K-dependent glycoprotein which is primarily synthesized in the liver. A deficiency in this protein or decreased activity, as seen in hereditary protein S deficiency, can lead to life-threatening thrombosis. Hereditary protein S deficiency is a rare disease as listed by the National Organization for Rare Disorders (NORD). Dural venous sinus thrombosis is a rare consequence of protein S deficiency and is associated with a risk of increased morbidity and mortality.It is also known to cause venous as well as arterial thromboembolic events commonly occurring in the deep leg and pelvic veins. We are reporting a case of 17 years old male without any risk factors and comorbidities presented with headache, giddiness and diplopia who has been diagnosed with cerebral venous sinus thrombosis and associated protein s deficiency.