Please note this guideline also covers nephritic and nephrotic syndromes.
Proteinuria is common in children and does not necessarily represent a pathological cause, often being seen in non-specific febrile illnesses (in conjunction with haematuria) and well as exercise.
Given the common finding of proteinuria in non-specific febrile illnesses in children, consideration of other findings is important when determining whether to refer children.
- Non-pathological proteinuria is commonly seen in non-specific febrile illnesses or exercise, and does not require further investigation. It is characterised by:
- proteinuria below nephrotic range (<40 mg/m2/hour* or <1000 mg/m2/day) but above normal range (>4 mg/m2/hour* or 100 mg/m2/day).
- no associated oedema, hypertension or renal insufficiency.
- Pathological proteinuria is either tubular or glomerular:
- tubular proteinuria usually presents with other symptoms prior to the proteinuria.
- glomerular proteinuria is usually in nephrotic range (see nephrotic syndrome below).
Nephrotic syndrome is characterised by:
- heavy proteinuria (>40 mg/m2/hour* or >1000 mg/m2/day).
- hypoalbuminuria (<25g/L)
- +/- hyperlipidaemia
- note - can also often have microscopic haematuria.
Nephritic syndrome is characterised by:
- renal insufficiency (oliguria, uraemia, raised creatinine)
- +/- oedema
- note - proteinuria is usually absent or very minimal.
* note that 4 mg/m2/hr corresponds to 20-25 mg/mmol, and 40 mg/m2/hr corresponds to 200-250 mg/mmol/hr in a spot urine sample.
- Proteinuria is common in children and does not necessarily represent a pathological cause, often being seen in non-specific febrile illnesses (in conjunction with haematuria) and well as exercise.
- Proteinuria more than (++) on dipstick is rarely innocent.
- Nephrotic syndrome is characterised by heavy proteinuria, oedema & hypoalbuminuria.
- Nephritic syndrome is characterised by haematuria, renal insufficiency & hypertension.
Proteinuria should be assessed for severity and associated features:
- Protein on dipstick more than (++) is rarely innocent.
- Urine laboratory analysis should be undertaken with persistent proteinuria, looking particularly for nephrotic range proteinuria (>40 mg/m2/hour* or >1000 mg/m2/day).
- Oedema associated with proteinuria generally represents nephrotic syndrome.
Initial workup should include
- measurement of blood pressure
- urea, electrolytes and creatinine
- serum albumin
Further investigation can be undertaken in consultation with paediatric services as required.