[Metabolic acidosis in children with newly diagnosed type 1 diabetes and risk factors of urolithiasis].

Introduction: Urolithiasis is increasingly being diagnosed in children. Some of the major risk factors for kidney stones are hipercalciuria, hiperoxaluria, hipocitraturia and hydrogen ion content measured by pH. Recently, more and more attention is being paid to the impact of diabetes type 1 and 2 on the development of nephrolithiasis especially in periods of poor metabolic control.

Aim Of The Study: was to evaluate the BRI (bonn risk index - rate of spontaneous crystallization of calcium oxalate), the concentration of oxalate, citrate and urine pH in children with acid-base balance disturbances occurring in patients with newly diagnosed type 1 diabetes (DMT1).

Material And Methods: The study group included 40 patients aged 6 to 17 years (average age ± SD: 12,58 ± 3,33) with newly diagnosed DMT1. The study was performed twice: at the beginning of the disease, immediately after the treatment of diabetic ketoacidosis (study I) and after obtaining satisfactory metabolic control (study II), that is after about two weeks. The control group consisted of 100 children (6-17 years, average age 12,34 ± 3,96) without symptoms suggestive of urolithiasis. In every child, a 24-hour urine sample was collected. BRI was implemented in the urine by his own semi-micro method.

Results: Ionized calcium level was significantly higher immediately after the diagnosis of type 1 diabetes compared to the control group (0,68±0,67 vs. 0,40 ± 0,18 mmol/l; p<0,001) and to study II (0,68 ± 0,67 vs. 0,28 ± 0,23 mmol/l; p=0,008). BRI value was significantly higher in early onset compared to the control group and the study II (3,18 ± 5,54 vs. 0,66 ± 0,52, p<0,001; 3,18 ± 5,54 vs. 0,64 ± 1,56; p=0,034). BRI correlated inversely with pH at admission to the hospital (r=-0,53, p=0,0023).

Conclusions: Metabolic alterations occurring during diabetic ketoacidosis at diagnosis of new type 1 diabetes may predispose to the development of the urinary stones, and thereby to the kidney damage.