Protein S deficiency presenting as deep vein thrombosis--a case report.

A rare case of spontaneous bilateral internal jugular vein (IJV) thrombosis is presented in absence of oral infection, malignancy, or intervention. Swelling of face, neck, and both upper limbs developed in a 30-year-old man 1 month before admission and after 4 weeks of use of nonpadded crutches. Computed tomography of the neck showed thrombus occluding both internal jugular veins extending to the opening of the superior vena cava. Protein S activity was found to be 30.3%, less than half of the lower limit of normal. Fibrinogen was 450 mg%, higher than normal. Protein C and antithrombin III were normal. The patient was treated conservatively, and discharged on aspirin 150 mg/day. Follow-up after 3 months showed no complications. It was concluded that the outcome in IJV thrombosis, caused by protein S deficiency, is usually good. The advantage of being aware of diagnosis is that physician can be more vigilant for potential complications and treat them earlier.