A case of idiopathic chronic interstitial nephritis progressed to renal failure without proteinuria nor hematuria

A case of idiopathic interstitial nephritis who underwent to chronic renal failure without history of hematuria nor proteinuria is discussed. A 46 years old woman who showed gradually elevation of serum creatinine (1.3-2.5 mg/dl) admitted on our hospital. On occasions of pregnancy, health examination or hospital visit, she has never been pointed out hematuria nor proteinuria. Immunological disorders such as SLE, metabolic diseases, urinary tract obstruction and chronic urinary tract infection were excluded by the examinations after admission. Because of the severe enzymuria (β2-microglobulin, N-acetyl glucosaminidase), chronic interstitial nephritis was considered, and renal biopsy was performed. Severe tubulointerstitial changes were observed histologically, however, glomerular damage was comparatively mild. From these results, she was diagnosed idiopathic chronic tubulointerstitial nephritis. In this case, hematuria and proteinuria were absent until severe renal dysfunction. This may be caused by that inflammation was located to the tubulointerstitial area. The observation of enzymuria seemed to be important to diagnosis and follow-up of the interstitial nephritis.