Protein S Deficiency, Central Retinal Artery Occlusion OD, and Reversal of Contralateral Carotid Artery Stenosis

Protein S Deficiency is a rare prethrombotic state characterized by recurrent venous thrombosis. However arterial thrombosis is rare in this condition. A 29 year old male with a family history of hypercoagulability had recurrent deep venous thrombosis and pulmonary emboli. The patient had the gradual onset of left sided headache accompanied by sudden painless visual loss in the left eye. The visual acuity was 20/20 OD and 20/200 OS. Initial fundoscopy a super temporal branch retinal artery occlusion OS. The neurologic examination was normal except for a soft right carotid bruit. Protein S levels were decreased to 57% (normal 78-130%) although Protein C, antiphospholipid antibodies and antithrombin Ill levels were normal.