Asymptomatic isolated microhaematuria: natural history of 136 children.

In a mass screening programme, 251 children with isolated microhaematuria were detected. Of these 251 children, 115 were excluded from the study because of microhaematuria secondary to a specific cause. The remaining 136 children were diagnosed as having asymptomatic isolated microhaematuria (ASH). Of these 136 children, 23 had evidence of urinary abnormalities in their family members. Red blood cell casts were evident in 31 children at their initial visit or during the follow-up period. Ten children had one or more episodes of macrohaematuria during the study. Renal biopsy was performed in 19 children because of indications of glomerular disease, and 13 of these 19 children had mild to moderate glomerulonephritis. None of these 136 children developed hypertension or renal impairment after a mean period of 7.4 years (range 6-13 years). Thirty-five children had normal urinary findings within 6 years of their initial visit, and 100 have had persistent microhaematuria without proteinuria throughout the follow-up period. The other child had microhaematuria with proteinuria greater than 1 g/m2 per day at the end of the study. This study suggests that the prognosis of ASH is good, and that renal biopsy is not indicated for children with ASH.