Acute tubulointerstitial nephritis in 21 Japanese children.

Patients and methods: Westudied 21 Japanese children aged 1.2 to 14.9 years with biopsy-proven acute tubulointerstitial nephritis (ATIN; 5 drug-induced, 7 infection-related, 3 tubulointerstitial nephritis and uveitis syndrome (TINU), and 6 unclassified) for clinical presentation, laboratory findings, and outcome to clarify the clinical features of the entity. All developed acute renal failure with peak BUN values from 25 to 164 mg/dl (mean 83 mg/dl) and peak serum creatinine values from 1.5 to 15.1 mg/dl (mean 6.5 mg/dl). All the 7 infection-related ATIN were associated with Yersinia pseudotuberculosis infection. Four ofthe 21 patients underwent dialysis therapy for anuria and I patient in the unclassified ATIN showed progression to chronic renal failure. Results: In 20 patients, renal insufficiency lasted for 6 to 73 days: 5 drug-induced; median and ranges 25 (12 33) days, 7 infection-related; 15 (6 - 22) days, 3 TINU; 65 (55- 73) days, and 5 unclassified; 24 (6- 34) days. Oral steroid therapy was introduced to the 3 TINU patients because of the prolonged renal dysfunction. Although it was effective in all, 2 of them showed a deterioration of clinical symptoms or renal function after reducing the dosage of steroid. Conclusion: Consequently, TINU patients required a longer period of time for the improvement of renal function compared to the other etiologies.