Renal venous thrombosis in infancy: long-term follow-up.

Sixteen children (11 male, 5 female) who developed renal venous thrombosis in the neonatal period or early infancy have been followed for periods varying from 29 months to 16 years (median 12 years) after initial diagnosis. Twelve patients presented with a hyperosmolar state, and in 4 the illness was preceded by severe birth asphyxia. The diagnosis was based on the findings of clinical and/or radiological renal enlargement (15 cases), haematuria (16 cases) and elevation in plasma urea (16 cases). Thrombocytopenia (13 cases), red cell fragmentation (13 cases) and oliguria (13 cases) were frequent associated findings. All 16 patients survived the acute illness, 1 patient died 3 years later from an unrelated event. On follow-up evaluation, 11 patients have normal renal function (glomerular filtration rate greater than 80 ml/min per 1.73 m2), 5 developed hypertension, 2 of whom responded to unilateral nephrectomy. Urinary concentrating capacity was subnormal (less than 800 mosmol/kg) in 7 of the 15 cases studied. Follow-up renal imaging studies were undertaken in 14 patients, and the imaging procedure was normal in only 2 of these. Of the remainder, 8 showed unilateral abnormality and 4 bilateral abnormality. Intellectual development was normal in 12 patients, mildly impaired in 1, and severely impaired in 3.