Glomerulonephritis

Question 1

What are the different aetiologies of GN?

Answer 1

Type 1 - anti-GMB glomerulonephritis - good pasture syndrome

Type 2 - immune complex mediated glomerulonephritis - eg IgA nephropathy, membranoproliferative glomerulonephritis, IgA vasculitis, lupus nephritis, poststreptococcal GN

Type 3 - GN associated with vasculitis - eg granulomatosis with polyangitis, microscopic polyangitis, eosinophilic granulomatosis with polyangitis

Question 2

What is the Pathophysiology behind RPGN?

Answer 2

Breaks in the glomerular capillary wall and dysfunction of the glomerular basement membrane (GBM) → leakage of plasma proteins (e.g., coagulation factors) and passage of inflammatory cells (macrophages, T cells) into Bowman space
Release of inflammatory cytokines → damage to the membrane of Bowman space and passage of cells from the interstitium into Bowman space
This causes the formation of fibrin clots and proliferation of cells (e.g., macrophages, fibroblasts, neutrophils, epithelial cells) → crescent moon formation → compression of the glomerulus → renal dysfunction

Question 3

What are the clinical features of RPGN?

Answer 3

Nephritic syndrome
Decreased urine output within days to weeks. Possibly Anuria
Fatigue
Pulmonary symptoms eg hemoptysis may occur

Question 4

What are the diagnostics for anti GMB disease? Lab findings, serology and biopsy findings

Answer 4

Lab findings - nephritic sediment - microhematuria (acanthocytes, RBC casts), non selective glomerular proteinuria, pyuria. Rapid rise of BUN and creatinine

Serology - antiglomerular basement membrane antibodies

Biopsy findings - linear pattern on immunofluorescence microscopy. Linear IgG deposits along the glomerular basement membrane

Question 5

What are the diagnostics for immune complex mediated glomerulonephritis? Lab findings, serology and biopsy findings

Answer 5

Lab findings - nephritic sediment - microhematuria (acanthocytes, RBC casts), non selective glomerular proteinuria, pyuria. Rapid rise of BUN and creatinine

Serology - decreased C3 complement (protein of immune system), lupus nephritis, anti dsDNA antibodies, post streptococcal GN

Biopsy findings - humps - granular pattern on immunofluorescence microscopy

Question 6

What are the diagnostics for immune glomerulonephritis associated with vasculitis? Lab findings, serology and biopsy findings

Answer 6

Lab findings - nephritic sediment - microhematuria (acanthocytes, RBC casts), non selective glomerular proteinuria, pyuria. Rapid rise of BUN and creatinine

Serology - granulomatosis with polyangitis, microscopic polyangitis

Biopsy findings - negative on immunofluorescence microscopy

Question 7

What is the treatment for RPGN?

Answer 7

Glucocorticoids and cyclophosphamide
Good pasture syndrome - plasmapheresis in addition to immunosuppression
RPGN due to ANCA associated vasculitis (granulomatosis with polyangitis, microscopic polyangitis) - combination therapy with glucocorticoids and rituximab