Acute tubulointerstitial nephritis in 21 Japanese children

Patients and methods: We studied 21 Japanese children aged 1.2 to 14.9 year s with biopsy-proven acute tubulointerstitial nephritis (ATIN; 5 drug-induc ed, 7 infection-related, 3 tubulointerstitial nephritis and uveitis syndrom e (TINU), and 6 unclassified) for clinical presentation, laboratory finding s, and outcome to clarify the clinical features of the entity. All develope d 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/d l). All the 7 infection-related ATIN were associated with Yersinia pseudo-t uberculosis infection. Four of the 21 patients underwent dialysis therapy f or anuria and 1 patient in the unclassified ATIN showed progression to chro nic 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 infect ion-related; 15 (6 - 22) days, 3 TINU; 65 (55 - 73) days, and 5 unclassifie d; 24 (6 - 34) days. Oral steroid therapy was introduced to the 3 TINU pati ents because of the prolonged renal dysfunction. Although it was effective in all, 2 of them showed a deterioration of clinical symptoms or renal func tion after reducing the dosage of steroid. Conclusion: Consequently, TINU p atients required a longer period of time for the improvement of renal funct ion compared to the other etiologies.