Prothrombotic abnormalities in children with venous thromboembolism

Purpose: The aim of this study was to determine the frequency of acquired or inherited prothrombotic disorders in a pediatric population with venous thromboembolism (VTE). Patients and Methods: From May 1992 to April 1998, 56 consecutive children with VTE were prospectively studied at a single center. Results: The median age was 8.4 years (range, 0.1-18 years). There was a male predominance. Fifty (89%) children had thrombosis in the lower venous system. Risk factors were detected in 54 (96%) children. Twenty-one (38%) thrombotic episodes were related to central venous lines. Family history of thrombosis was positive in 13 (23%) patients. In 26 (46%) patients, a prothrombotic disorder was detected. Nine of them had inherited disorders (protein C deficiency, 5 patients; protein S deficiency, 3 patients;Factor V Leiden mutation, 1 patient), and 13 children had acquired disorders (antiphospholipid antibodies, 5 patients, antithrombin deficiency, 8 patients). The remaining four showed combined abnormalities (Factor V Leiden mutation associated with inherited protein S deficiency, 1 patient; acquired antithrombin deficiency, 2 patients and inherited antithrombin deficiency, 1 patient). Conclusions: In the series, a high percentage of prothrombotic disorders was detected; thus, a complete hemostatic evaluation should be performed in all of the children with VTE whether the patients have one or more risk factors.