Clinical, demographic, and laboratory characteristics of children with nephrolithiasis

Abstract

While the incidence of pediatric kidney stones appears to be increasing, little is known about the demographic, clinical, laboratory, imaging, and management variables in this patient population. We sought to describe various characteristics of our stone-forming pediatric population. To that end, we retrospectively reviewed the charts of pediatric patients with nephrolithiasis confirmed by imaging. Data were collected on multiple variables from each patient and analyzed for trends. For body mass index (BMI) controls, data from the general pediatrics population similar to our nephrolithiasis population were used. Data on 155 pediatric nephrolithiasis patients were analyzed. Of the 54 calculi available for analysis, 98% were calcium-based. Low urine volume, elevated supersaturation of calcium phosphate, elevated supersaturation of calcium oxalate, and hypercalciuria were the most commonly identified abnormalities on analysis of 24-hour urine collections. Our stone-forming population did not have a higher BMI than our general pediatrics population, making it unlikely that obesity is a risk factor for nephrolithiasis in children. More girls presented with their first stone during adolescence, suggesting a role for reproductive hormones contributing to stone risk, while boys tended to present more commonly at a younger age, though this did not reach statistical significance. These intriguing findings warrant further investigation.

Pediatric Nephrolithiasis: Trend, Evaluation and Management: A Systematic Review

“…The classic adult presentation with flank pain radiated to the groin is not common and almost agedependent (33,44,50). Although, adolescents usually present colicky pain similarity to adults, younger children have nonspecific symptoms including abdominal pain, nausea and vomiting or irritability.…”

“…Mixed calcium oxalate and calcium phosphate are present in more than 10% and magnesium ammonium phosphate (infection related) stone is reported in more than 17% of patients (33,36,37).…”

“…Nonspecific and localized pain is typical of infants and young children with nephrolithiasis. Hematuria and uncharacteristic abdominal pain are common in only 10% to 14% of all pediatric cases (33,37,51). However, nephrolithiasis is discovered incidentally, during imaging evaluation for other reasons, and remains asymptomatic for a long time (24,33).…”

“…Nevertheless, recent studies indicated the low volume of using this test. In case that the collection is not possible, the urine spot urine samples may be helpful but cannot replace 24-hour urine collection (33,(53)(54)(55)(56). Normal urinary values in spot urine samples and 24-hour samples are shown in Tables 3 and 4.…”

“…In fact, super saturation of ions in urine such as calcium and oxalate directly depend on the volume of urine, hence an appropriate hydration could protect the stone formation. Furthermore, it has been demonstrated that high intake of salt (sodium) increases the excretion of urinary calcium and stone formation (32,33). Although calcium in appropriate amounts may prevent oxalate absorption from the intestine, low intake of dietary calcium contributes to nephrolithiasis in adolescents (13).…”