Outcome a lungo termine dei pazienti pediatrici con rene singolo. Valutazione di marker laboratoristici e strumentali di danno renale

Objectives: to evaluate the correlation between glomerular filtration rate (GFR) estimated using 99mTc diethylene-triamine pentaacetic acid (Tc-DTPA) and 1) renal function laboratory markers (creatinine, cystatin C, proteinuria) 2) equations for estimating GFR 3) evaluation parameters of renal growth on ultrasound Materials and methods: 118 patients between 0 and 18 years of age with congenital solitary kidney were recruited. At every visit, weight, height, levels of creatinine, cystatin C and proteinuria and renal ultrasound length were recorded. The estimated GFR was calculated using equations based on serum creatinine (Schwartz), cystatin C (Zappitelli, Filler, Grubb and Bokenkamp) and both creatinine and cystatin C (Zappitelli's equation). Renal growth was determined as a ratio between renal ultrasound length and body height (USL/H), the percentage difference between measured and expected renal length for age (delta%) and the presence or absence of compensatory hypertrophy. DTPA-GFR was measured in 74 children. Results: mean follow-up was 2.1 ± 0.9 years. 65% were male. None developed chronic renal insufficiency. Mean DTPA-GFR value was 135±44 ml/min/1.73m², mean serum creatinine and cystatin C values were 0.47±0.17 mg/dl and 1±0.4 mg/L, respectively. Mean ultrasound renal length was 100±17mm, mean USL/H ratio was 0.8±0 and mean delta% 1,13±11,4. 66% patients developed renal hypertrophy. The only significant correlations were 1) inverse between DTPA-GFR and creatinine (p=<.001) and 2) linear between DTPA-GFR and USL/H (p=<.001). Discussion: The study demonstrated that, as seen in other nephropathies, serum creatinine and renal ultrasound are both valid instruments in the follow-up of patients with congenital solitary kidney. The main limit of this study was that it was not possible to establish a cut-off value for risk parameters such as USL/H, as none of the patients developed chronic renal insufficiency.