A healthy kidney filters the proteins in the blood and keeps them in the body; only a trace amount of protein passes into the urine. Finding protein on a test understandably worries parents — yet in children, the most common causes of protein in the urine are temporary and harmless.

Harmless (Temporary) Causes

  • A period of febrile illness
  • Intense exercise
  • Dehydration, exposure to cold
  • Orthostatic proteinuria: Common during adolescence; protein leaks while standing and disappears when lying down. If the first morning urine is clean, this is most likely the diagnosis, and it is benign.

For this reason, a diagnosis is never made from a single positive result; the test is repeated during a healthy period, using the first morning urine.

Significant Causes

Persistent and marked proteinuria can be a sign of kidney disease. The best known of these in children is nephrotic syndrome:

  • Swelling (edema) of the eyelids in the morning and of the legs during the day
  • Foamy urine
  • Weight gain (fluid accumulation), abdominal swelling

These findings should be evaluated without delay; nephrotic syndrome generally responds well to treatment in children but requires regular follow-up. Glomerulonephritis and diabetes are among the other causes.

How Is Follow-Up Done?

If positivity recurs, the urine protein/creatinine ratio, blood tests, and blood pressure measurement are used for evaluation; if necessary, the child is referred to pediatric nephrology.

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This article is for general information purposes only; it does not replace diagnosis and treatment. For any concerns about your child's health, always consult a pediatric health and diseases specialist.

Uzm. Dr. Hasan Keleş — Specialist in Pediatric Health and Diseases, Gaziantep