TOPIC 7 : rapidly progressive glomerulonephritis

Question 1

what is RPGN and how is it characterised?

Answer 1

It is a clinical syndrome and not a specific etiologic form of GN. It is characterised by:

1) rapid and progressive loss of renal function
2) lab findings typical of nephritic syndrome
3) often severe oliguria
4) systemic symptoms of vasculitis

-if untreated, it leads to death from renal failure within a period of days to months.

Question 2

etiology and pathophysiology of RPGN (3 types)

Answer 2

= CRESCENTIC GN may be cause by a number of different diseases, some restricted to the kidney and some systemic.
Crescents in Bowman’s spave on H&E composed of fibrin and macrophages

3 types:
~12% of pts have anti-GBM antibody-mediated crescentic GN with or without lung involvement
~44% have immune complex GN with crescents
~44% have pauci immune crescentic GN

you can use IF, to see the pattern or the GN for diagnosis

Question 3

IF pattern: linear anti-basement membrane AB
AKA
anti-GBM antibody-mediated crescentic GN

Answer 3

If there are also antibodies bound to the pulmonary alveolar capillary BM= Goodpasture Syndrome

So there are AB against collagen in both glomerular and alveolar BM
Presents with HEMATURIA &HEMOPTYSIS
Classically in young, adult males.

affected persons may benefit from plasmapheresis which removes pathogenic AB from the circulation

Question 4

IF pattern: granular immune complex deposition
AKA
immune complex-mediated crescentic GN

Answer 4

Most commonly due to PSGN or diffuse proliferative GN

-DPGN: due to AB-AN complex deposition usually subendothelial, most common type of renal disease in SLE

Affected persons do not benefit from plasmapheresis

Question 5

IF pattern: NEGATIVE - Pauci immune CGN

Answer 5

defined by lack of anti-GBM antibodies or of significant immune complex deposition.

• antineutrophil cytoplasmic antibodies (ANCA) are typically found in the serum which have an etiopathologic role in some vasculitides.
• in some instances therefore, CGN is a component of s systemic vascilitis (wegener’s/ microscopic poly / churg-strauss) but in some cases however it is limited to the kidney and thus called idiopathic.
• WG: C-ANCA
• MP: P-ANCA
• CS: P -ANCA but also has granulomatous inflammation, eosinophilia and asthma

Question 6

treatment and prognosis

Answer 6

treat:

• high dose IV steroids& cyclophosphamide
• some pts benefit from plasmapheresis ( anti-gbm)

prognosis:
-5 year survival ~80%
the prognosis can be roughly related to the fraction of involved glomeruli: pts whom crescents present in less than 80% of glomeruli have better prognosis than those whom percentage of crescents is higher