Prediction of the long-term outcome in acute interstitial nephritis.

Fourteen patients with acute interstitial nephritis have been followed for an average of 64 months. Initial renal failure estimated by a reciprocal of serum creatinine improved rapidly and linearly within 6 to 8 weeks ("early improvement"). A slow improvement of GFR followed within one year, showing a new base line level of renal function, which was assessed as normal in five patients and was reduced in seven patients. Two patients died of non-renal disease. Final GFR was closely correlated with a degree of "early improvement", ages at onset and severity of interstitial lesions. The results suggest, 1) these indices are of much value in predicting long-term prognosis and 2) a certain degree of permanent impairment of renal function is rather common in the disease.