IgA nephropathy (Berger's disease)

Definition

IgA nephropathy (Berger's disease, mesangioproliferative nephropathy) is a focal segmental GN, and is the most common cause of GN in adults
Can be a primary condition, but it can also secondary if there is increased production or impaired clearance of immune complexes
Characterised by presence of prominent IgA deposits in mesangial regions

Risk factors

Coeliac disease - intestinal mucosal defects
Liver disease - defective hepatobiliary clearance of IgA complexes
Ankylosing spondylitis
Prior URTI
Neoplasia
Infection

Pathology

IgA nephropathy is caused by immune complexes containing IgA, specifically IgA1 (IgA2 is non-nephritogenic).
Unknown antigens
?defective galactosylation of the IgA1 antibody may make it immunogenic, and autoantibodies against the IgA1 are the cause of the IC formation
The ICs cause granular IgA1 deposits in mesangium
leads to mesangial proliferation and matrix production
C3 (but not C1a or C4) can be found in the glomerulus, suggests that the alternative C' pathway is activated

Presentation

Most commonly frank haematuria (may be recurrent episodes)
Often a preceding history of URTI in previous 1-2 days

Examination
? Oedema (suggestive of nephrotic syndrome)

Bedside tests

Urine dipstick will show haematuria (30-40% have microscopic haematuria), and often proteinuria

Investigations

Blood investigations

Renal impairment is common
Complement - usually normal (c.f. post-streptococcal GN, where C' is low)

Renal biopsy

Deposition of IgA-containing deposits in the mesangium
Mesangial cell proliferation
Accumulation of mesangial matrix
IF: IgA and C3

Complications

5-10% present with the nephritic syndrome
Rarely can present with RPGN
20% progress to renal failure
Healing of damaged glomeruli can cause sclerosis.
Extensive glomerulosclerosis increases the chance of progressing to FSGS

Also a clinical overlap with HSP

Management

Hypertension
ACE-I
Steroids

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License