Investigation

Purpose of investigations in nephrotic syndrome (NS) is

• (1) confirm the clinical diagnosis;
• (2) seek a possible cause;
• (3) assess renal function; and
• (4) identify biochemical disorders related to the nephrotic state e.g. hypercoagulability, hypovolaemia, hyperlipidaemia

Finding of heavy proteinuria (3-4+) on dipstick and oedema in a child in the developed world usually means a diagnosis of NS. Proteinuria needs to be quantified as the protein: creatinine ratio or per litre of urine

• proteinuria is usually measured on first morning spot voids
  • microscopic haematuria may be present in up to 25% of children with steroid-sensitive NS and should not be a contraindication to empirical steroid therapy
• recommended investigations in a child (2)
  • urine dipstick analysis (protein and blood)
  • first morning urine for protein:creatinine ratio
  • urine for microscopy, sensitivity and culture
  • serum electrolytes, albumin, triglyceride and cholesterol, calcium
  • FBC
    • haemoglobin and packed cell volume
  • complement C3 and C4 levels
  • varicella zoster serology
  • hepatitis B and C serology
  • ASO titre, anti-DNAse B, lupus antibody serology (ANA, ENA, ds- DNA), ANCA if atypical presenting features

Reference:

• (1) Lancet (1995); 346 (8969):148-52.
• (2) Dolon MN, Gill D. Management of nephrotic syndrome. Paediatrics and Child Health 2002:369-374.