[Solitary kidney. Study of renal morphology and function in 95 children]

The aim of the study was to evaluate renal growth and function of solitary kidney in paediatric patients.

A prospective study was performed in a fifteen years period between 1988 and 2003 in paediatric patients with a solitary kidney, in a Children's Hospital. All the following parameters were evaluated every year: age, sex, ethiology, elapsed time since the concept of solitary kidney was assessed (ET), blood pressure, renal function measured by GFR, urinary excretion of solutes, concentration ability and microalbuminuria (MA). DMSA was made at the beginning and every five years and renal ultrasonography was carried out every two years. Two groups were made depending of nephrourologic malformations in the remanent kidney and/or antecedents of pyelonephritis: Group I with antecedents of pyelonephritis and/or malformations; Group II, nor antecedents of pyelonephritis neither malformations.

Ninety five patients were evaluated, 69% (n = 66) were males and 31% (n = 29) were females, with an age at diagnosis of 3.5 yr (ranged 0.1-17 yrs). ET was 9.2 yrs (range 1-20 yrs). The ethiology was: Nephrectomy of the contralateral kidney 39 patients (pts) (41%), renal agenesis (RA) 47 pts (49%) and nonfunctioning multicystic displastic kidney (MCDK) 9 pts (9.4%). Functional alterations were found in 18 pts (19%), such as MA in 12 pts (12.6%), decreased GRF in 5 pts (5.5%) and hypertension in 3 pts (3.2%). It was observed more significant functional alterations in the patients of the Group I (58%) versus Group II (9%) (p < 0.001). There was in Group II a significant correlation between kidney size and GFR (p < 0.01, r = 0.3), and between kidney size and ET (P < 0.05; r = 0.3).

Any alteration in the renal function was observed in the 12.6% of the children. The most frequent affected parameter of renal damage was MA, followed by GFR reduction. Arterial hypertension was not a prominent finding. Alterations have been less frequently found in RA and MCDK of the Group II, so clinical reviews should be made with a lesser frequency.