Biopsy-proven paediatric tubulointerstitial nephritis.

This series represents a subset of paediatric TIN patients in whom there was a clinical indication for a renal biopsy, hence presenting with more severe disease than previously reported. This group were more likely to have no identifiable underlying cause and an increased requirement for corticosteroid treatment. Furthermore, more than half of the cases developed chronic kidney disease (CKD) with impaired kidney function.