THE PARENTS of a 3-year-old boy sought consultation regarding a brownish discoloration of their son's clothing and bed sheets noted after episodes of enuresis. The parents report that the discoloration became more intense over time. Their son had been healthy and without other complaints. There was no history of illness or trauma. There were no urinary tract symptoms. The medical history was unremarkable as was the family history.
There were no abnormal findings noted on the physical examination. Urine was obtained for examination. The urine was clear and yellow in color with a specific gravity of 1.010, pH of 6.5, and without evidence of hemoglobin, myoglobin, red or white blood cells, or protein. A sample of the urine was observed at room temperature for 48 hours with the color changes shown in Figure 1.