[Serum cystatin C concentration in children with urinary stones]. / Stezenie cystatyny C w surowicy dzieci z kamica moczowa.

UNLABELLED: Stone formation precedes long period, when the crystals are accumulated in basement membranes of renal tubules and intestinal tissue. Accumulated, inside of renal tubules crystals and stones in urinary tract cause urinary tract obstruction, what may lead to impairment of renal function. The aim of work was the assessment of serum cystatin C (cys C) concentration in children with urolithiasis, confirmed by the presence of renal stones in renal pelvis in comparison to serum creatinine concentration and creatinine clearance (Cr cl). MATERIAL AND METHODS: Examined group (B) consisted of 30 children aged (13.08 +/- 4.14 years) with urolithiasis, which was divided into 3 subgroups (I, II, Ill) in dependence on stones' diameter (0.35-1.6cm). Control group (C) consisted of 26 healthy children at the same age. Nephelometric method was used to determine serum cystatin C level, Jaffe method to assess serum creatinine and the Schwartz formula to estimate glomerular filtration rate. RESULTS: In control group (C) serum cys C did not exceed 0.95 mg/l. In group B serum cystatin C and serum creatinine concentration and Cr cl was similar to the results of control group (p > 0.05). However in 16% of children with urolithiasis, in whom the stones of 0.8-1.6cm diameter were found in both renal pelvis, the concentration of serum cys C exceed 1.2 mg/l, and the value differed significantly from the results of control group (p < 0.05). A weak positive correlation between cys C and creatinine concentration and also between cys C and Cr cl was found. The serum cys C concentration in children with single stones of 0.35-0.8 diameter was normal. CONCLUSION: Serum cystatin C increases with increased degrees of urolithiasis assessed by stone size and their number in kidney.

Assessment of serum cystatin C in children with congenital solitary kidney.

The aim of the study was to assess serum cystatin C level in children with a congenital solitary kidney, depending on their age and compensatory overgrowth of the kidney. The study group (I) consisted of 36 children, 3-21 years of age (median 10.8 years), with a congenital solitary kidney and no other urinary defects. The control group (C) contained 36 healthy children, 5-21 years old (median 10.9 years). Nephelometric methods were used to determine serum cystatin C level, the Jaffe method to assess creatinine concentration and the Schwartz formula to estimate glomerular filtration rate. Kidney length was measured with the patient in a supine position, and overgrowth was estimated (O%) in comparison with the respective kidney in the control group. Serum cystatin C level in group I was higher than that in the control group (P<0.05). Increased values, above 0.95 mg/l, were found in 16/36 (44%) children aged 12-21 years. Glomerular filtration rate (GFR, estimated by the Schwartz formula) and creatinine level in group I were similar to those of the control group (P>0.05). Increased kidney length was found (median 18.2%). Cystatin C concentration was positively correlated with O% (r=0.406, P<0.01) and kidney length to child height ratio (L/H) (r=0.376, P<0.05). We conclude that Increased serum cystatin C concentration in patients with a unilateral congenital solitary kidney occurs after 12 years of age and correlates with compensatory overgrowth of the kidney.