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Protein C deficiency. A cause of unusual or unexplained thrombosis
D F Tollefson1, K D Friedman, R A Marlar
1Department of Surgery, Medical College of Wisconsin, Milwaukee.
Insights
Familial hypercoagulable states, like protein C deficiency, increase venous thrombosis risk. Early diagnosis and slow-start warfarin therapy are crucial for managing this inherited condition.
Area of Science:
- Hematology
- Genetics
- Vascular Medicine
Background:
- Familial hypercoagulable states are inherited disorders affecting coagulation proteins.
- Deficiencies in proteins like antithrombin III, plasminogen, protein C, and protein S predispose individuals to thrombosis.
- Venous thrombosis is a common manifestation, typically developing in adulthood.
Observation:
- A 15-month period revealed five patients with venous thrombosis and protein C deficiency.
- Four patients had deep venous thrombosis (recurrent in two), and one experienced mesenteric venous thrombosis.
- The affected kindred suggested autosomal dominant inheritance of protein C deficiency.
Findings:
- Patients diagnosed between 28-41 years old presented with low protein C levels (34-67 U/dL).
- Initial treatment involved heparin sodium, followed by long-term oral anticoagulation with warfarin sodium.
- Warfarin initiation requires a slow start without a loading dose to prevent skin necrosis.
Implications:
- Protein C deficiency is a recently recognized risk factor for venous thrombosis.
- Prompt measurement of protein C levels is recommended for patients with unexplained, recurrent, or early-onset thrombosis.
- Long-term warfarin anticoagulation is the recommended treatment for symptomatic protein C deficiency.
Abstract:
Familial hypercoagulable states are a collection of syndromes characterized by an inherited deficiency of various proteins involved in the control of coagulation and include antithrombin III, plasminogen, protein C, and protein S. Affected patients usually develop venous thrombosis as adults. During a 15-month interval, we identified five patients with venous thrombosis accompanied by protein C deficiency. Four patients presented with deep venous thrombosis, which was recurrent in two, and one patient developed mesenteric venous thrombosis. The kindred of this last patient suggested an autosomal dominant genetic transmission of protein C deficiency. Patients' ages at the time of diagnosis of disease ranged from 28 to 41 years. All patients had low levels of protein C (range, 34 to 67 U/dL; normal, 70 to 130 U/dL). All patients were treated with heparin sodium immediately and then given long-term oral anticoagulation therapy with warfarin sodium. Protein C deficiency is a predisposing factor to the development of venous thrombosis that has only recently been recognized. Treatment of symptomatic protein C deficiency requires short-term heparin therapy followed by long-term oral anticoagulation therapy with warfarin. Oral anticoagulation treatment must be initiated slowly with no loading dose to avoid warfarin-associated skin necrosis. Patients with unexplained or unusual thrombosis, especially if it occurs at an early age, and patients with recurrent episodes of lower limb venous thrombosis should have their protein C levels measured. If a deficiency is documented, long-term warfarin anticoagulation therapy is recommended.