Renal outcome of neonatal renal venous thrombosis: review of 28 patients and effectiveness of fibrinolytics and heparin in 10 patients.

OBJECTIVES: Neonatal renal venous thrombosis is a rare disorder that can result in severe renal damage. To evaluate the experience over 10 years and review the effectiveness of fibrinolytic and/or heparin therapy, chart reviews were performed for newborns with renal venous thrombosis. PATIENTS, INTERVENTIONS, AND OUTCOME MEASURES: Twenty-eight newborns with renal venous thrombosis were treated at Children's Hospitals and Clinics of Minnesota and Fairview University Medical Center from 1991 to 2001.
RESULTS: Unilateral involvement was noted in 25 neonates (89%) and bilateral involvement in 3 (11%). Unilateral renal venous thrombosis affected mostly term infants, whereas 2 of 3 infants with bilateral renal venous thrombosis were <32 weeks' gestational age (birth weight: 745-1505 g). One mother had antiphospholipid syndrome. Of 11 neonates evaluated for congenital thrombophilia, 1 had the factor V Leiden mutation. Ten neonates received either unfractionated or low molecular weight heparin for 3 days to 7 months. Three infants with unilateral renal venous thrombosis treated with heparin alone did not seem to benefit from such therapy. Seven neonates were treated with fibrinolytics and unfractionated heparin (4 neonates with unilateral renal venous thrombosis and 3 with bilateral renal venous thrombosis). Treatment with fibrinolytics did not result in restoration of renal function in the 4 neonates with unilateral renal venous thrombosis but was associated with return of almost normal function in the 2 neonates with bilateral renal venous thrombosis who received fibrinolytics immediately after renal venous thrombosis diagnosis. Two neonates treated with fibrinolytics suffered bleeding complications at the area of adrenal hemorrhage. Two neonates (not treated for renal venous thrombosis) died as a result of underlying disease.
CONCLUSIONS: Most neonatal renal venous thrombosis is unilateral and does not respond to fibrinolytic therapy and heparin. The use of fibrinolytics may prevent chronic renal failure in neonates with bilateral renal venous thrombosis if begun within 24 hours of diagnosis. Fibrinolytic therapy, however, is associated with a risk of bleeding, specifically if there is an associated adrenal hemorrhage.