Unexpected urine crystals and hematuria.

An otherwise healthy 6-year-old boy presented to the emergency department after falling out of bed and sustaining a testicular injury. The examination and evaluation, including urinalysis (revealing hematuria) and ultrasound, were suggestive of minor injury but were otherwise unremarkable. The patient was started on amoxicillin and had orders for a repeat urinalysis in a week. The microscopy review of the urine sample a week later demonstrated numerous crystals and moderate hematuria (Fig.1).