Nephritic syndromes

Question 1

What is the best way to diagnose IgA nephropathy?

Answer 1

Renal biopsy

Question 2

What will a biopsy show in IgA nephropathy?

Answer 2

Normally shows IgA deposition within the mesangium causing proliferation and inflammation.

Question 3

How do pts with IgA nephropathy present?

Answer 3

Typically patients present with recurrent gross or microscopic haematuria following (12-72h) an upper respiratory tract infection.
Most classically seen in boys, 9-15 yrs old
(Mild proteinuria may also be present. On examination, hypertension may be present)

Question 4

What conditions can cause a nephritic picture?

Answer 4

SHARP AIM

SLE
Henoch-Schönlein purpura
Anti glomerular basement membrane (GBM) disease (AKA goodpasture's disease)
Rapidly Progressive glomerulonephritis (GN)
Post-streptococcal GN
Alport's synrome
IgA nephropathy (AKA Berger's disease)
Membranoproliferative GN

Question 5

How can IgA nephropathy be differentiated from post streptococcal glomerulonephritis?

Answer 5

IgA nephropathy occurs 1-2 days post-infection (vs. 1-3 weeks post-infection in PSGN)
Renal biopsy in IgA nephropathy shows IgA immune complex deposits (vs. IgG immune complex deposits in PSGN)

Question 6

How is IgA nephropathy managed?

Answer 6

Conservative: Monitoring and optimising fluid balance
Medical:
Optimise blood pressure
Angiotensin Converting Enzyme (ACE) inhibitor/Angiotensin Receptor Blocker reduce proteinuria and protect renal function
Corticosteroids can also help to decrease proteinuria (less effective here than in minimal change)

Question 7

How are nephritic syndromes characterised?

Answer 7

Haematuria
<3.5g/day proteinuria
Hypertension

Question 8

List the spectrum of syndromes

Answer 8

Pure nephrotic syndrome: minimal change disease.
Nephrotic syndrome with some haematuria: membraneous glomerulonephritis, focal segmental glomerulosclerosis.
Nephritic syndrome with nephrotic-range proteinuria: membrano-proliferative (also known as mesangio-capillary) glomerulonephritis.
Pure nephritic syndrome: post-streptocloccal glomerulonephritis, IgA nephropathy/Henoch-Schonlein purpura, infective endocarditis, Goodpasture’s disease, vasculitis.

Question 9

What is the pathophysiology of PSGN?

Answer 9

A humoral response is mounted against Streptococcus pyogenes, resulting in antibody-antigen binding and the formation of immune complexes. This depletes complement components and lowers C3 levels. Over time, the immune complexes deposit within the glomerulus and disrupt the glomerular basement membrane, causing a nephritic syndrome in certain individuals a few weeks after the initial Streptococcal infection.