Nephrolithiasis in a portuguese pediatric population

• Main Author: Andrade,Joana V
• Publication Date: 2018
• Other Authors: Bota,Sofia, Francisco,Telma, Santos,Raquel, Neto,Gisela, Abranches,Margarida
• Format: Article
• Language: eng
• Source: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Download full: http://scielo.pt/scielo.php?script=sci_arttext&pid=S0872-01692018000300005
• topic: nephrolithiasis; kidney stone; children; Portuguese; metabolic disease; obesity

Introduction and Aims: Nephrolithiasis incidence in children has increased considerably. It is associated with substantial morbidity, recurrence and increased adulthood cardiovascular risk and chronic kidney disease. A thorough investigation is essential, as rare forms of urolithiasis have increased risk of renal failure. We aim to determine the epidemiology and outcomes of a pediatric population with nephrolithiasis presented in a nephrology unit of a tertiary centre. Methods: Retrospective study of the records of all children (<18 years) with nephrolithiasis diagnosis between 2008-17. Clinical features, etiology, recurrence, treatment, and outcomes were evaluated and compared throughout the study period through two equal periods (2008-12 versus 2013-17). Results: We identified 80 cases: isolated nephrolithiasis (86%) and associated with nephrocalcinosis (14%). Mean follow-up was 36 months (14-120). Median age at presentation was 8.6 years [3 months - 17 years]: 21% < 2 years-old and 46% ≥ 10 years. The annual ratio of referrals for nephrolithiasis increased on average 1.2% per year [0.3-11.8%]. Multiple etiological factors were present in 34%. A metabolic abnormality was identified in 54%: hypocitraturia (34%), hypercalcuria (24%), hyperoxaluria (15%), hyperuricosuria (15%) and cystinuria (1%), without age predominance (p=0.2). Urinary tract infection (24%) was the next most significant etiology and was more frequent below 2 years of age (p=0.001) and associated with struvite calculi (p=0.033). Median age at diagnosis was significantly lower in the study’s first half (5 vs 10 years; p=0.019) and an infectious etiology was more frequent (p=0.043). In a logistic-regression analysis, a family history of nephrolithiasis was associated with a metabolic cause (p<0.01). Sixty-three percent became stone free and 24% had recurrence. Discussion: Nephrolithiasis new referrals gradually increased throughout the study period. The most common etiology was metabolic, which is usually responsible for nephrolithiasis appearance and its recurrence, emphasizing the need for a complete evaluation.