Nephrotic syndrome

Definition

• Syndrome characterized by:
  • Significant proteinuria > 3g/day
  • Hyperlipidemia/lipiduria
  • Anasarca
  • Hypoalbuminemia <35g/L

Differential Diagnosis

• Non-proliferative glomerulonephritis
  • Minimal change disease
    • Primary
    • Drugs
      • NSAIDs and COX-2 inhibitors
      • Ampicillin, rifampicin, cephalosporins
      • Lithium
      • D-penicillamine and tiopronin
      • Pamidronate
      • Sulfasalazine and 5-ASAs
      • Interferon-gamma
    • Neosplasms
      • Hodgkin lymphoma
      • Non-Hodgkin lymphoma
      • Leukemia
    • Lupus nephritis V (membranous nephritis)
  • Focal segmental glomerulosclerosis
    • Primary
    • Severe obesity and other hyperfiltration syndromes
    • Infections
      • HIV
      • Parvovirus B19
      • CMV
      • EBV
    • Drugs
      • Heroin
      • Interferons
      • Pamidronate
      • Anabolic steroids
      • mTOR inhibitos
      • Calcineurin inhibitos
      • Anthracyclines
      • Lithium
    • Other
      • Sickle cell anemia
      • Thrombotic microangiopathy
      • Genetic disorders
  • Membranous nephropathy
    • Primary
    • Lupus
    • Drugs
      • Gold
      • Penicillamine
      • NSAIDs
    • Infections
      • Hepatitis B and C
      • Malaria
      • Syphilis
    • Neoplasms
      • Non-Hodgkin lymphoma
      • Solid cancers
    • IgG4 disease

Most common causes

• Membranous nephropathy (24 percent)
• Minimal change disease (16 percent)
• Lupus (14 percent)
• FSGS (12 percent): more common in black patients
• Amyloidosis (6 to 17 percent): more common in older patients
• Membranoproliferative glomerulonephritis (7 percent)
• IgA nephropathy (6 percent)

Epidemiology

• If < 20 years old
  • Minimal change (70%)
  • Membranous (20%)
  • Focal segmental glomerulosclerosis (10%)
• If > 20 years old
  • Membranous (70%)
  • Minimal change (20%)
  • Focal segmental glomerulosclerosis (10%)

Management

• If < 20 years old
  • Treat empirically with steroids, as the majority are primary minimal change disease
• If > 20 years old
  • Needs kidney biopsy to direct treatment