Obstructive aortic and renal thrombosis in the newborn--spontaneous recovery.

A 13-day-old infant presented with acute renal failure secondary to a large thrombus formation involving the umbilical aorta and both renal arteries. The initial clinical manifestations were hematuria, followed by anuria, severe dehydration, grunting respirations, and cyanosis of her feet. She was treated with intravenous fluids and peritoneal dialysis. At the onset, there was no blood flow into the abdominal aorta or into the kidneys. Heparinization and fibrinolytic therapies were unsuccessful in dissolving the clot. However, the aortic clot recanalized spontaneously a few weeks later, but the renal arteries remained permanently occluded. Despite this, her kidneys showed blood flow bilaterally and she recovered her renal function, probably by reperfusing her kidneys through collateral circulation. Malignant hypertension ensued after improvement of renal function, but it could be controlled by appropriate antihypertensive therapy.