IgA Nephropathy

Background

• Also known as Berger’s disease
• Most common form of idiopathic glomerulonephritis resulting in CKD
  • Around 30-40% of patients go on to develop end-stage CKD within 20 years.
  • Usually presents in young adults and there is a slight male predominance (males tend to have a poorer prognosis)
  • Can be associated with a number of other conditions
    • e.g. Henoch Schonlein purpura; SLE; autoimmune hepatitis; ankylosing spondylitis

Pathophysiology

• Characterised by IgA- and C3- complex deposition in the glomerular mesangium
• It is uncertain as to the exact mechanism by which this occurs but patients with IgAN seem to have an raised level of circulating IgA
  • It is thought that a specific type of IgA (galactose-deficient IgA) is responsible
• As the disease progresses, several features may be seen (all contribute towards a poorer prognosis- collectively known as Oxford classification)
  • Increased mesangial cellularity
  • Segmental glomerulosclerosis
  • Endocapillary hypercellularity
  • Tubular atrophy/interstitial fibrosis

Presentation

• Usually presents with frank haematuria following an upper respiratory tract infection
  • May also present with microscopic haematuria (more common in older adults) or an AKI
• Usually this resolves in several days
  • If haematuria persists, there is usually progression to renal failure

Investigation

• Urinalysis (dipstick)
  • Usually shows protein and blood
• Urine microscopy (red cells, leukocytes and casts)
• Urinary protein and creatinine (24 hour-collection)
• Plasma IgA may be raised in around 50% of cases
• Renal biopsy will give a definitive diagnosis

Management

• Manage any hypertension – ACE inhibitors have shown to be beneficial
  • ACEIs plus Angiotensin receptor blockers may have additional benefit
• Steroids (a 6 months course of prednisolone) is thought to be protective against progression to ESKD
• Regular monitoring of renal function is important