05 - Nefrologia 21-2 - Paediatric nephrolithiasis

Aims: Nephrolithiasis and nephrocalcinosis are progressive diseases that can lead to renal impairment. The aim of this analysis was to evaluate aetiological factors, metabolic screening, diagnostic algorithm, treatment, prophylactic measures and follow-up in children with nephrolithiasis and nephrocalcinosis. Patients and methods: Retrospective study of 63 children (36 males, 27 females) with nephrolithiasis and/or nephrocalcinosis followed up in the Paediatric Nephrology Unit of Coimbra Paediatric Hospital during a period of 20 years. The parameters analysed were gender, age at diagnosis, year of diagnosis, calculi site, metabolic factors, urinary tract abnormalities, treatment, follow-up, personal history of urinary tract infections (UTI) and family history of nephrolithiasis. All children underwent a metabolic screening that included plasma biochemistry evaluation, blood gas analysis and 24 hour urine collection for assessment of lithogenic factors. All the data and statistical analysis were handled using SPSS 10. Results: We detected 46 cases of nephrolithiasis, 15 of nephrocalcinosis and 2 of nephrolithiasis and nephrocalcinosis. The median age at diagnosis was 6 years for nephrolithiasis (1-16) and 1.4 years for nephrocalcinosis (0.1-14), 48 (76%) of the cases were diagnosed in the last ten years. In 19 (30%) of the children the diagnosis was made following UTI and in 10 (16%) following an episode of renal colic. Family history of nephrolithiasis was found in 25 cases (40%). Eight children (13%) had abdominal X-rays and all underwent ultrasonography. Eighty five percent of the calculi were found in the kidneys, 13% in the ureters and 2% in the bladder. Nephrocalcinosis was bilateral in 100% of the cases. The main aetiological factors were UTI (30%), urinary tract abnormalities (22%), tubular renal acidosis (14%) and hypercalciuria (11%). During follow-up, 21 (33%) were discharged calculi free and 7 (11%) were transferred to adult hospitals. Conclusions: Investigating and treating UTI is necessary to prevent subsequent renal impairment. Equally so, metabolic and structural abnormalities that predispose to nephrocalcinosis and nephrolithiasis should be investigated and treated. Key-Words: Calculi; children; nephrocalcinosis; nephrolithiasis; urinary tract infection.