A 12-hour-old baby boy is referred for further evaluation after passing red-colored urine. Dipstick testing was positive for hematuria. He is a first-born, with his mother being 29 years of age. Following an unremarkable antenatal period, he was born at 40 weeks of gestation via an uncomplicated vaginal delivery. He cried immediately after birth and had Apgar scores of 9, 10, and 10 at 1, 5, and 10 minutes respectively. His birth weight was 3.150 kg. Breastfeeding was established within the first half-hour. There is no maternal history of miscarriages, bleeding disorders, or other medical conditions. His family history is positive for type 2 diabetes in his grandmother and two uncles. A complete blood count reveals a WBC count of 6,400/mm3, hemoglobin of 15.2 g/dL, hematocrit of 38%, and platelet count of 150,000/mm3; all of these are within the normal range. Urinalysis shows a field full of red blood cells, with dipstick negativity for nitrites and leukocyte esterase. A coagulation profile demonstrates normal PT, APTT, and TT times.
Urea: 50 mg/dL (17-72) Serum creatinine: 0.5 mg/dL (<1) Serum Na+, K+, Cl-: within normal parameters
Ultrasound imaging of the abdomen shows the right kidney to be enlarged (~6.3 cm length), with loss of corticomedullary demarcation, and echogenic streaks in the lower pole. Color Doppler studies show reversed end-diastolic flow in the right renal artery and significantly reduced flow in the right renal vein. There is normal blood flow in the inferior vena cava.
Contrast computed tomography (CT) shows the right kidney to be enlarged (6.3 x 3.2 cm). There is a partial thrombosis of the right renal vein. The thrombus has not extended into the inferior vena cava.
Septic screen: negative The echocardiogram shows no structural or valvular cardiac defects.