Introduction

IgA nephropathy (also known as Berger's disease) is the commonest cause of glomerulonephritis worldwide. It classically presents as macroscopic haematuria in young people following an upper respiratory tract infection.

Epidemiology

  • Incidence: 3.00 cases per 100,000 person-years
  • Peak incidence: 20-30 years
  • Sex ratio: more common in males 3:1
Condition Relative
incidence
Henoch-Schonlein purpura3.33
IgA nephropathy1
Post-streptococcal glomerulonephritis0.10
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Aetiology

Associated conditions

Pathophysiology

Pathophysiology
  • thought to be caused by mesangial deposition of IgA immune complexes
  • there is considerable pathological overlap with Henoch-Schonlein purpura (HSP)
  • histology: mesangial hypercellularity, positive immunofluorescence for IgA & C3

Clinical features

Presentations
  • young male, recurrent episodes of macroscopic haematuria
  • typically associated with mucosal infections e.g., URTI
  • nephrotic range proteinuria is rare
  • renal failure is unusual and seen in a minority of patients

Differential diagnosis

Differentiating between IgA nephropathy and post-streptococcal glomerulonephritis
  • post-streptococcal glomerulonephritis is associated with low complement levels
  • main symptom in post-streptococcal glomerulonephritis is proteinuria (although haematuria can occur)
  • there is typically an interval between URTI and the onset of renal problems in post-streptococcal glomerulonephritis

Management

Management
  • steroids/immunosuppressants not be shown to be useful

Prognosis

Prognosis
  • 25% of patients develop ESRF
  • markers of good prognosis: frank haematuria
  • markers of poor prognosis: male gender, proteinuria (especially > 2 g/day), hypertension, smoking, hyperlipidaemia, ACE genotype DD