Thromboembolic risk in children with nephrotic syndrome.

The in vivo activation of the hemostatic system was evaluated in 14 children (4-13 years old) with nephrotic syndrome at different stages of the disease. The blood platelet count, beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), fibrinogen, the coagulation inhibitors antithrombin III and protein C (ATIII:Ag and PC:Ag), and D-dimers were determined. Platelet number was significantly higher at the onset of the disease than in the next stages (p less than 0.05). beta-TG, PF4 and fibrinogen were significantly increased as compared with controls at the onset (p less than 0.001) and decreased progressively during the course of the disease without reaching the control values. Blood coagulation inhibitors behaved differently; PC was higher in patients than in controls at all stages (p less than 0.05) whereas ATIII values were significantly decreased at the onset (p less than 0.05), but increased during the course the disease (p less than 0.01). No changes were observed in the D-dimer plasma levels. These data suggest that the thrombotic risk in nephrotic syndrome is particularly evident at the onset of the disease, and appears to be due mainly to changes in platelet number and function, and to increased fibrinogen levels rather than to alterations of plasma anticoagulant factors.