IgA Nephropathy in Children: A Multicenter Study in Poland.

IgA nephropathy (IgAN) is the most common form of glomerulonephritis in pediatric population. The clinical presentation of the disease in children ranges from microscopic hematuria to end-stage kidney disease. The aim of the study was to retrospectively assess clinical and kidney biopsy features in children with IgAN. We assessed a cohort of 140 children, 88 boys, 52 girls with the diagnosis of IgAN in the period of 2000-2015, entered into the national Polish pediatric IgAN registry. The assessment included the following: proteinuria, hematuria, glomerular filtration rate (GFR), arterial blood pressure, and the renal pathological changes according to the Oxford classification and crescents formation, as modifiable and unmodifiable risk factors. The incidence of IgAN in Poland was set at 9.3 new cases per year. The mean age at onset of IgAN was 11.9 ± 4.3 years, and the most common presentation of the disease was the nephritic syndrome, recognized in 52 % of patients. Kidney biopsy was performed, on average, 1.3 ± 2.0 years after onset of disease. Based on the ROC analysis, a cut-off age at onset of disease for GFR <90 mL/min/1.73 m2 (risk factor of progression) was calculated as 13.9 years. Unmodifiable lesions: segmental sclerosis, tubular atrophy/interstitial fibrosis (S1, T1-2) in the Oxford classification and crescents in kidney biopsy were significantly more common in Gr 1 (>13.9 years) compared with Gr 2 (<13.9 years), despite a significantly shorter time to kidney biopsy in the former. We conclude that IgAN in children may be an insidious disease. A regular urine analysis, especially after respiratory tract infections, seems the best way for an early detection of the disease.

Increased Serum IgA in Children with IgA Nephropathy, Severity of Kidney Biopsy Findings and Long-Term Outcomes.

The aim of the study was to determine whether an elevated IgA level at the time of the diagnosis of IgA nephropathy has an effect on the severity of kidney biopsy findings and long-term outcomes in children. We retrospectively studied 89 children with IgA nephropathy who were stratified into Group 1- elevated serum IgA and Group 2 - normal serum IgA at baseline. The level of IgA, proteinuria, hematuria, glomerular filtration rate (GFR) and hypertension (HTN) were compared at baseline and after the end of the follow-up period of 4.0 ± 3.1 years. Kidney biopsy findings were evaluated using the Oxford classification. The evaluation of treatment included immunosuppressive therapy and renoprotection with angiotensin converting-enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB), or no treatment. The elevated serum IgA was found in 46 (52 %) patients and normal serum IgA level was found in 43 (48 %) patients. No differences were found between the two groups regarding the mean age of patients, proteinuria, and the number of patients with reduced GFR or HTN at baseline. In kidney biopsy, mesangial proliferation and segmental sclerosis were significantly more common in Group 1 compared with Group 2 (p < 0.05). Immunosuppressive therapy was used in 67 % children in Group 1 and 75 % children in Group 2. The Kaplan-Meier survival curves for renal function (with normal GFR) and persistent proteinuria did not differ significantly depending on the serum IgA level at baseline. We conclude that in IgA nephropathy the elevated serum IgA at baseline may be associated with mesangial proliferation and segmental sclerosis contribute to glomerulosclerosis, but has no effect on the presence of proteinuria or on the worsening of kidney function during several years of disease course.

[Uric acid metabolism in children with hyperuricosuria]. / Metabolizm kwasu moczowego u dzieci z hiperurykozuria doniesienie wstepne.

We treated 39 children with hyperuricosuria (18 boys and 21 girls aged between 6 and 11 years). Treatment consisted of increased fluid intake, low salt and low purine diet and urine alkalization up to pH 6.5-6.8. We have selected two groups of patients with different uric acid [UA] metabolism parameters. In group I (21 children) mean value of serum UA was 2.52 mg/dL, mean urine UA excretion was 13.11 mg/kg/d and UA FE was 21.51%. In group II (18 children) mean value of serum UA was 4.7 mg/dL, mean urine UA excretion was 12.8 mg/kg/d and UA FE was 10.9%. In group I, treatment did not normalize uricosuria (13.57 mg/kg/d), urine pH was elevated (6.56). In group II uricosuria was diminished (8.37 mg/kg/d), urine pH was 6.37. 1. Disturbances of tubular secretion may be suspected in some children with hyperuricosuria and without hypouricemia. 2. The maintenance of urine pH within normal values is the basic of treatment in children with hyperuricosuria. 3. In children suspected of tubular transport disturbances appropriate tests of uric acid metabolism should be performed.

[Conservative treatment of urolithiasis in children]. / Leczenie zachowawcze kamicy ukladu moczowego u dzieci.

Treatment of urolithiasis depends on the stone and secretion renal tubular transport disturbances. Conservative treatment of urolithiasis and prevention of stone formation in children should consist of: adequate fluid intake, low salt and animal protein diet in all stone formers; calcium-oxalate stones: diet containing a proper amount of dairy product, low oxalate diet, if indicated: thiazide diuretics, magnesium salts, citrate; uric acid stones: low purine diet, alkalization of urine up to pH 6.5-7.0, if indicated: allopurinol; infection stones: treatment of the urinary tract infection, low phosphate diet; cystinuria: low animal protein diet, alkalization of urine up to pH 7.0, if indicated: captopril, d-penicillamine.

[Evaluation of treatment of uric acid urolithiasis and prevention of stone formation in children]. / Ocena skutecznosci leczenia zachowawczego kamicy moczanowej u dzieci i zapobiegania nawrotom.

The objective of this study was to evaluate treatment of uric acid urolithiasis and prevention of uric acid stone formation in children. We treated 18 children (11 boys and 7 girls) with uric acid urolithiasis. Complete dissolution of stones was achieved in 16 children (89%). During a two year follow-up period, 14 children (78%) were recurrence free.