IgA nephropathy; focal glomerulonephritis; Berger's disease

Introduction

Also see IgA vasculitis

Etiology

• increased mucosal IgA production
• associated disorders*
  • advanced chronic liver disease, cirrhosis
  • celiac disease
  • dermatitis herpetiformis
  • ankylosing spondylitis
  • Henoch Schonlein purpura (acute leukocytoclastic vasculitis)
  • inflammatory bowel disease
  • HIV1 infection

* may be associated with a systemic disorder

Epidemiology

• most common glomerulonephropathy worldwide
• frequently occurs in young males (2nd & 3rd decades)

Pathology

• glomerulonephritis affecting a small proportion of glomeruli
• mesangial proliferation
• immunofluorescence shows IgA deposits in the glomerular mesangium
• generally polymeric IgA1 originating in secretory mucosal system
• partly due to aberrant or incomplete galactosylation of IgA1 molecules

Genetics

• susceptibility to IgA neuropathy associated with defects in C1GALT1 gene

Clinical manifestations

• variable manifestations from asymptomatic microscopic hematuria with or without proteinuria to rapidly progessive glomerulonephritis
• an antecedent upper respiratory tract infection may be noted
  • hematuria 1-2 days after a sore throat
  • generally no latency between infection & acute kidney injury
• hematuria may be noted after vigorous physical exercise or trauma
• urine is usually brown rather than red
  • clots are unusual
• gross hematuria may occur synchronously with respiratory infection or gastrointestinal infection
• may occur as disease restricted to the kidney or as part of a syndrome (see etiology)
• rapidly progessive glomerulonephritis may be associated with
  • acute renal failure, hypertension, edema, proteinuria, hematuria

Laboratory

• urinalysis
  • hematuria (microscopic or macroscopic)
  • erythrocyte casts
  • proteinuria, including nephrotic syndrome, may be present
• serum IgA is increased in 50% of patients
  • levels do NOT correlated with disease severity
• serum complement levels are normal
• complete blood count may show erythrocytosis
• skin biopsy for IgA is NOT helpful
• renal biopsy with immunofluorescence studies is diagnostic
• monitor serum creatinine, urinalysis

Complications

• acute renal failure with macroscopic hematuria
• acute tubular necrosis

Differential diagnosis

• postinfectious glomerulonephritis
• IgA vasculitis

Management

• control blood pressure (alone sufficient in most patients)
• ACE inhibitors slow progression of renal disease; ARB if ACE inhibitor not tolerated
• omega-3 fatty acids (fish oil & perhaps flax-seed oil) slows progression of disease in high-risk patients
• broad-spectrum antibiotics not useful
• benefit of immunosuppressive agents is unclear
  • benefit of corticosteroid for proteinuria is controversial
    • progression of renal failure may be attenuated
    • serious infections may occur, including fatalities
  • add alkylating agent to corticosteroid if renal insufficiency
  • benefit/risk ratio unacceptable
• prevention
  • in adults age 19-64 years vaccination with both PCV13 & PPSV23 is indicated
    • with advanced kidney disease a 2nd dose of PPSV23 is recommended 5 years after the 1st
  • annual influenza virus vaccine
• prognosis is generally good
  • poor prognostic signs:
    • heavy proteinuria
      • absence of proteinuria portends benign course managed conservatively
    • hypertension
    • renal insufficiency
  • 20% of patients may reach end-stage renal disease in 20 years
• renal transplantation:
  • disease often recurs
  • generally not clinically significant

More general terms

• mesangioproliferative glomerulonephritis

Additional terms

• acute leukocytoclastic vasculitis (Henoch-Schonlein purpura; IgA vasculitis)

Patient information

IgA nephropathy patient information