MILD DILATATION OF THE FETAL KIDNEY - A FOLLOW-UP-STUDY

Objective To assess morbidity in children with mild prenatally detecte d pelvicalyceal dilatation and to document the natural history of this ultrasound finding in post-natal life. Patients and methods A retrosp ective (on-going) study was carried out in 29 children (39 kidneys) wi th mild dilatation confined to the pelvis and/or calices confirmed on initial post-natal ultrasound scan. Re-evaluation was carried out at a mean age of 4.2 years (range 1.5-7.8). Clinically, each patient's his tory, height, weight and blood pressure were recorded. On ultrasound e xamination the renal length, collecting system appearances and dimensi ons were recorded.Results Vesico-ureteric reflux was demonstrated in 1 of 14 infants who underwent neonatal micturating cys-tourethrography. During cumulative follow-up totalling 122 years, there were only two documented episodes of urological morbidity, i.e. one episode of unexp lained haematuria and one of urinary tract infection. By a mean age of 4.2 years the ultrasound appearances had reverted to normal in 69% of kidneys. In 31% dilatation persisted and was unchanged or diminished in severity. No case of increasing dilatation was seen. Renal growth w as normal in 97% of kidneys. Conclusions Mild dilatation of the fetal urinary tract is a common prenatal ultrasound finding. When confined t o the renal pelvis and/or calices it is of doubtful clinical significa nce and is associated with a low level of morbidity in infancy and ear ly childhood. Invasive investigation in post-natal life is not justifi ed.