[Neonatal renal vein thrombosis: early diagnosis using Doppler ultrasonography and long-term sequelae]

To describe the physiopathological mechanisms in perinatal renal vein thrombosis and the associated risk factors, with emphasis on the clinical and radiological characteristics and on the long-term evolution.

We retrospectively studied a total of 11 cases of neonatal renal vein thrombosis; the mean age of patients at diagnosis was 3 days. We analyzed the type of presentation, the clinical manifestations, and the findings at B-mode and Doppler ultrasonography, as well as the treatment undertaken and the long-term sequelae.

At the time of diagnosis, the triad of a palpable mass, unequivocal hematuria, and thrombocytopenia was present in only 63.63% of patients. A prothrombotic risk factor was identified in the newborn or mother in 45.45% of cases. At ultrasonographic examination, all newborns had enlarged kidneys and in all cases it was impossible to differentiate between the renal cortex and the renal medulla. In 4 of the 11 cases, hyperechogenic intramedullary linear images characteristic of the initial stage of thrombosis were identified. Functional follow-up studies using DMSA (dimercaptosuccinic acid) and MAG-3 (mercaptoacetyltriglycine acid) revealed morphological abnormalities in all patients; 7 patients had a nonfunctioning kidney.

Visualizing echogenic bands within the medulla should alert radiologists to the initial phase of renal vein thrombosis and enable the appropriate treatment to be administered. With the exception of cases discovered before birth, renal vein thrombosis has a poor prognosis, with atrophy and renal failure in the long term.