HDCN Article Review/Hyperlink

Nieuwhof C, Doorenbos C, Grave W, deHeer F, deLeeuw P, Zeppenfeldt E, van Breda Vriesman PJC

A prospective study of the natural history of idiopathic non- proteinuric hematuria

Kidney Int (Jan) 49:222-224 1996

Hematuria is a common problem for which renal consultation is frequently sought. There are few studies that have examined the issues of etiology and long term prognosis of patients with hematuria in a prospective manner. As part of their multicenter prospective study of glomerulonephritis, Nieuwhof et al investigated 49 patients with gross (18 patients) or microscopic (31 patients) hematuria which was persistent for 6 months. These patients had a negative urologic workup, did not have any systemic diseases, liver disease, hypertension or familial diseases associated with hematuria. Patients were allowed to have no more than 500 mg/day of proteinuria and all had normal renal function. All underwent renal biopsy and were followed prospectively for a median of 11 years. Of the 49 patients, idiopathic IgA nephropathy and thin glomerular basement membrane ( GBM ) disease accounted for 12 and 13 patients, respectively. Three patients had interstitial nephritis, one had focal global sclerosis and twenty had normal histology.

In patients with IgA nephropathy, thin GBM disease and normal histology, GFR was well maintained over the follow-up period. Microscopic hematuria persisted in the majority of patients with glomerular diseases but resolved in 65% of patients with normal histology some of whom had symptoms of urolithiasis. Patients with interstitial nephritis and focal global sclerosis were found to have diminished renal function. The disturbing finding is that of the 29 patients with renal pathology 15 developed hypertension compared to one of 20 with normal renal histology.

Comments: The strengths of the study are: patients were studied prospectively, renal histology was examined in all patients and the follow-up period was a median of 11 years. The good news is renal function is well maintained in hematuric patients with glomerular diseases who have normal or only mildly increased protein losses in the urine. The bad news is that patients with interstitial nephritis may progressively lose renal function and that hypertension appears in more than 50% of patients with renal pathology. One would have liked to have seen a more thorough investigation of nephrolithiasis in patients with normal histology. B.S. Kasinath, M.D.