Antiphospholipid antibodies and coagulation regulatory protein abnormalities in children with pulmonary emboli.

PURPOSE: To evaluate the demographics, presentation, family history, and laboratory findings in children with clinically recognized pulmonary emboli.

METHODS: Data were collected about children with clinically recognized pulmonary emboli from 1987 to 1994 at two pediatric hematology referral centers.

RESULTS: Sixteen children, mean age 11.8 years (standard deviation 4.69 years) including 11 boys were affected. Lower extremity thromboses were present in 7/14 children evaluated. Eight of the 16 children were apparently well before development of pulmonary emboli; seven were found to have antiphospholipid antibodies. None of the 15 children tested were antithrombin III deficient. One of 14 children tested was protein C deficient. Three of 13 children tested were protein S deficient or had a free protein S antigen at the fifth percentile. One of 10 children tested had an acquired dysfibrinogenemia. Two of nine children tested had the Factor V Leiden mutation.

CONCLUSIONS: Our limited data suggest at least 70% of children with pulmonary emboli referred for hematology evaluation have antiphospholipid antibodies and coagulation regulatory protein abnormalities.