DEFINITION

SIGNIFICANT PROTEINURIA

  • >4- 40 mg/ m2 /hr of protein/ 24 hr urine

Or

  • Spot urine protein creatinine ratio  >0.2- 2 mg/mg.

NEPHROTIC range proteinuria

  • >40 mg/ m2 /hr of protein/ 24 hr urine

Or

  • Spot urine protein creatinine ratio  > 2 mg/mg

If proteinuria persists on > 3 occasions then its persistent proteinuria.

Nephrotic syndrome is proteinuria(nephrotic range) with hypoalbuminuria and oedema.

CAUSES OF PROTEINURIA

TRANSIENT

  • Fever.
  • Exercise.
  • Stress.
  • Dehydration.

ORTHOSTATIC( significant proteinuria on standing up, but not on lying down)

GLOMERULAR CAUSES-

  • Minimal change disease.
  • Focal/ segmental glomerulosclerosis.
  • Glomerulonephritis.
  • Membranous nephropathy.
  • Amyloidosis.
  • Diabetic nephropathy.
  • Post infectious.
  • Acute tubular necrosis.
  • IgA nephropathy.
  • Polycystic kidneys.
  • Wilsons/ Cystinosis.

CAUSES OF PERSISTENT PROTEINURIA

Capture

DIAGNOSIS

History-

  • Headache.
  • Oliguria/ haematuria.
  • Joint pains/ rashes.
  • Hypertension/ repeated UTI.
  • Symptoms of tumour-weight loss.
  • Medications.

Family history (cystic kidney disease/ deafness/ renal disease/ dialysis)

Physical Examination.

  • Growth retardation.
  • Blood pressure.
  • Flank pain/ oedema.
  • Anaemia.

Laboratory Testing

  • Urinary dipsticks (screening method )
    • Trace (<20 mg/dl)
    • 1+ (30 mg/dl)
    • 2+ (100 mg/dl)
    • 3+ (300 mg/dl)
    • 4+ (>2000 mg/dl)
  • Random urine protein creatinine ratio (mg/dl) –
    • Normal  <0.2
    • Nephrotic range is >2
  • 24 hr urinary protein excretion- Gold standard test
    • Normal  <4 mg/m2/hr
    • Nephrotic range is 4-40 mg/m2/hr
    • Nephrotic range is > 40 mg/m2/hr.

Laboratory Workup In asymptomatic patient( No other complications)

  • Repeat urine dipstick needs to be repeated weekly
  • Make sure proteinuria is transient.
  • Follow up with 6 monthly dip sticks

In persistent proteinuria

Orthostatic proteinuria( benign condition)-

  • Test with split a 24 hr urine collection( morning sample)
  • Urine is collected separately in lying/supine or upright position
  • Early morning urine protein creatinine ratio <0.2mg/mg
  • Protein excretion from lying/supine position  <60/m2/day
Management is to follow up with regular dip sticks. If proteinuria worsens, then needs further evaluation.

OTHER INVESTIGATIONS-

  • Blood tests
  • Renal function tests (BUN and creatinine) with Phosphorus
  • Anti nuclear antibiotic/ Anti double stranded DNA
  • Ant neutrophil antibodies( C and p-ANCA)
  • Serum albumin
  • Lipid profile
  • Renal and Bladder ultrasound
  • Complement levels( C3 and C4)
  • Infection workup( Hepatitis B and C/ HIV)

Referral to a paediatric nephrologist.

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