Nephrocalcinosis in children: a retrospective multi-centre study

Aim: To review the data of children with NC and to analyse aetiology, clinical manifestations, growth and renal function at presentation; to relate growth and renal function to changes in NC in patients with a follow-up of at least 12 months. Methods: Data of 41 children from four institutions were gathered retrospectively. Results: Presenting symptoms were failure to thrive in the first year of life (41%), urinary tract infections, bladder voiding dysfunction or abdominal pain (17%) and psychomotor delay (10%). In 24% of cases NC was detected incidentally. Glomerular function at diagnosis was normal in 83% of children. During a median follow-up of 4 yrs and 5 months in 28 patients, growth standard deviation score improved from a median of -2.2 to -1.0 and glomerular function remained stable in 89% of patients, in spite of worsening of the degree of NC in 62% of cases. The most frequent causes of NC were hereditary tubulopathies and vitamin D intoxication. Conclusion: Our results show that the treatment of the underlying conditions is associated with catch-up growth and stabilization of glomerular function in many children, but not with the reduction in the degree of NC in the majority of cases. We believe that early recognition of conditions leading to NC is clinically useful and suggest a diagnostic flowchart, which may be helpful in the approach to NC.