Asymptomatic microscopic haematuria in young males

The study involved 120 young males (aged 20.5 +/- 2.5 years) having undergone successful kidney biopsy because of asymptomatic haematuria with the aims to assess the prevalence of histological diagnosis and the natural history of the disease.

The patients were selected from the population of conscripts who were referred to our clinic as a result of asymptomatic microhaematuria. All patients had a negative history of kidney disease, normal creatinine clearance (Ccr), while extrarenal causes of microhaematuria were excluded. The patients were divided into a group of 62 patients with isolated microhaematuria (IMH; proteinuria < 0.3 g/day) and a group of 58 patients with asymptomatic microhaematuria and proteinuria (AMHP; proteinuria > 0.3 g/day). After kidney biopsy patients were monitored for 3-9 years.

Normal biopsies and minor abnormalities were more frequent in IMH than in AMHP patients, who had IgA nephritis more frequently and significantly higher total pathohistological score. Based on the clinical and histological features, recommendations on patients' ability for military service were made. During the follow-up period, normal Ccr maintained in all patients. Macrohaematuria appeared in 42 patients and proteinuria worsened in eight patients (seven with AMHP). Urinary abnormalities disappeared in 20 patients with IMH and in eight with AMHP (p = 0.04).

Minimal histological changes and disappearance of urinary abnormalities were more frequent in IMH than in AMHP patients. Kidney biopsy is useful only in patients with AMHP but it is not necessary in IMH patients.