Tissue plasminogen activator therapy of renal venous thrombosis

Background: Neonatal renal venous thrombosis (RVT) is a well documented and potentially fatal entity with long-term renal morbidity.
Case Report: We report an unusual case of bilateral RVT in a premature infant with persistent pulmonary hypertension and the use of recombinant tissue plasminogen activator (r-TPA) was associated with a successful outcome and final complete recovery. A 2850 gm, 36-week preterm male baby was born to a 29-year-old woman via emergency cesarean section due to preeclampsia and fetal heart rate deceleration. The infant required high frequency mechanical ventilation for poor respiratory effort and low oxygenation, insertion of umbilical catheters for resuscitation, cardiac massages for stabilizing blood pressure, and claforan and ampicillin for presumed sepsis. Laboratory studies revealed hemoglobin, 12.3 g/dl; hematocrit, 39.3%; platelet, 53,000/mm3; blood urea nitrogen, 26 mg/dL; creatinine, 2.8 mg/dL; and metabolic acidosis on day 3. Bilateral abdominal palpable mass and gross hematuria with blood clot was found on day 3 and the renal ultrasound showed swollen kidneys with prominent echopoor medullary pyramids. Given the extensive nature of the thrombus and the presence of progressively deteriorated renal function, systemic thrombolytic therapy using r-TPA at a dose of 0.1 mg/kg/hr was administered for 8 hours on day 10 after correction of thrombocytopenia on days 3 and 6. Renal functions returned to normal on day 19 and the follow-up ultrasound showed normal renal sizes at 7 months old.
Conclusions: The presence of either a flank mass, hematuria, or thrombocytopenia in a neonate with risk factors should prompt investigation for RVT in order to prevent long-term renal morbidity.