Nephritic Syndrome

A clinical constellation resulting from inflammatory injury of the glomeruli

Aetiology

Primary Causes

  • Acute post-infectious (post-streptococcal) glomerulonephritis
  • IgA nephropathy (Berger disease)
  • Membranoproliferative glomerulonephritis
  • Rapidly progressive glomerulonephritis (crescentic GN)

Secondary Causes

  • Systemic lupus erythematosus (lupus nephritis)
  • Vasculitides (ANCA-associated)
  • Anti–glomerular basement membrane (anti-GBM) disease
  • Infective endocarditis–associated GN

Pathophysiology

notion image

Clinical presentation

  • Renal Manifestations
    • Gross Hematuria
      • Classically cola- or tea-colored urine
      • Due to oxidation of hemoglobin in acidic urine
    • Proteinuria (usually sub-nephrotic, <3.5 g/day)
    • Oliguria
    • Edema
      • Periorbital edema (especially in the morning)
      • Dependent edema (ankles, sacrum)
  • Systemic Features
    • Hypertension
    • Malaise
    • Headache
    • Signs related to underlying systemic disease

Investigations

Bloods

  • U+Es

Examination of urine

  • Urinalysis - haematuria, proteinuria
  • Urine microscopy - dysmorphic RBCs, RBC and granular casts, lipiduria
  • Urine protein: creatinine ratio/24 hour urine to quantify proteinuria

Renal biopsy

Light microscopy
  • Usually see hypercellularity - inflammatory and reactive proliferations
  • Can see sclerosis - on-going damage
  • May see crescents - bad, indicates rapidly progressive GMN
  • Granulomas - GPA, sarcoid
Electon microscopy
  • Can see immune complex depositions in the basement membrane
Immunoflourescence
  • Shows what kind of antibody and what distribution e.g. linear IgG in Goodpasture's

Management

Non-immunosupressive

  • Anti-hypertensives - target BP <130/80
  • ACEi/ARBs
  • Diuretics
  • Statins

Immunosuppression

  • Drugs e.g. corticosteroids, azathioprine
  • Plasmapharesis - TPE (therapeutic plasma exchange)
  • Antibodies - IV Ig, monoclonal T or B cell antibodies