Primary tubulointerstitial nephritis may be Acute (see table Causes of Acute Tubulointerstitial Nephritis) Chronic (see table Causes of Chronic Tubulointerstitial Nephritis) Acute tubulointerstitial nephritis Acute tubulointerstitial nephritis (ATIN) involves an inflammatory infiltrate and edema affecting the renal interstitium that often develops over days to months.