• nephrology
• hematuria

A previously healthy 16-year-old boy was referred for a 3-day history of gross haematuria without pain or other symptoms. Family history was negative for renal disease or hearing loss. Physical examination showed a tall and slim boy, blood pressure was 112/68 mm Hg, heart rate was 58/min, there was no oedema and the body weight was referred as stable.

Remarkably, during the observation period, the boy passed alternately dark reddish and light pink urine; urinary output was normal (1.2 mL/kg/hour).

Urine dipstick showed haematuria (4+) with proteinuria (2+). Repeated microscope urine analysis showed erythrocytes with both glomerular and postglomerular appearance, without casts.

Laboratory tests, including creatinine, C3, C4, electrolyte, serum albumin, immune-globulins, cholesterol and triglycerids, were normal, while autoantibodies (anti-neutrophil cytoplasmic antibodies, antinuclear antibodies and anti-DNA) and antistreptolysin O were negative. Proteinuria in 24-hour urine collection was quantified as 4 g (normal values <150 mg/24 hours). Renal ultrasonography showed normal kidneys and bladder, without stones. A CT scan of his abdomen was performed (figures 1 and 2).