Glomerulonephritis Flashcards
Definition
An immunologically mediated inflammation of the renal glomeruli
Aetiology
• There are loads of different types of glomerulonephritis with different aetiologies
• Some types are caused by the deposition of antigen-antibody complexes in the
glomeruli
• This leads to inflammation and activation of complement and coagulation cascades
• The immune complexes may form within the glomerulus (more common) or be deposited from the circulation `
Associations
• The antigens to which the antibodies are produced are UNKNOWN but may be
associated with:
o Bacteria (e.g. Streptococcus viridans, Staphylococci)
o Viruses (e.g. HBV, HCB, measles, mumps, EBV)
o Protozoal (e.g. Plasmodium malariae, schistosomiasis)
o Inflammatory/Systemic diseases (e.g. SLE, vasculitis, cryoglobulinaemia)
o Drugs (e.g. gold, penicillinamine)
o Tumour
Classifications
Classification is based on the site of nephron pathology and its distribution
o Minimal-change Glomerulonephritis
• Light microscopy - minimal change
• Electron microscopy - loss of epithelial foot process
o Membranous Glomerulonephritis
• Thickening of glomerular basement membrane (GBM) from immune complex deposition
• Associated with Goodpasture’s Syndrome
o Membranoproliferative Glomerulonephritis (MPGN)
• Thickening of GBM
• Mesangial cell proliferation and interdeposition
o Focal segmental glomerulosclerosis
• Glomerular scarring
• Associated with HIV
o Focal segmental proliferative glomerulonephritis
• Mesangial and endothelial cell proliferation
• Focal = involvement of some glomeruli
• Segmental = involvement of parts of individual glomeruli
o Diffuse proliferative glomerulonephritis
• Same as above but affects ALL glomeruli
o IgA Nephropathy
• Mesangial cell proliferation
• Mesangial IgA and C3 deposits
o Crescentic Glomerulonephritis
• Crescent formation by macrophages and epithelial cells, which fills up Bowman’s space
o Focal Segmental Necrotising Glomerulonephritis
• Peripheral capillary loop necrosis (occurs in granulomatosis with polyangiitis, microscopy polyarteritis and other vasculitides)
• Often evolves into crescentic glomerulonephritis
NOTE: cryoglobulins are immunoglobulins that precipitate in the cold
Epidemiology
Accounts for 25% of the cases of chronic renal failure
Presenting symptoms
- Haematuria
- Subcutaneous oedema
- Polyuria or oliguria
- History of recent infection
- Symptoms of uraemia or renal failure (acute and chronic)
Signs on physical examination
- Hypertension
- Proteinuria
- Haematuria (especially in IgA nephropathy)
- Renal failure
- Nephrotic syndrome
- Nephritic syndrome
Nephrotic syndrome
• Nephrotic syndrome - consists of a TRIAD of:
o Proteinuria > 3.5 g/24 hrs
o Low serum albumin < 24 g/L
o Oedema
o NOTE: due to the hypoalbuminaema, the liver tries to compensate and increases production of lipids, causing hyperlipidaemia
Nephritic syndrome
• Nephritic syndrome (TRIAD: hypertension + proteinuria + haematuria)
o Syndrome comprising of signs of nephritis
o Pores in the podocytes are large enough to allow protein AND red blood cells to pass into the urine
o MAIN FEATURE: Haematuria
• This is in contrast to nephrotic syndrome, which is mainly concerned with
proteinuria
o There may also be red cell casts in the urine - indicative of glomerular damage
o Other features:
• Proteinuria
• Hypertension
• Low urine output (due to decreased renal function)
o NOTE: in nephrotic syndrome, only PROTEINS are moving into the urine
Investigations (bloods)
o FBC o U&Es + creatinine o LFTs (check albumin) o Lipid profile o Complement studies
o Antibodies: • ANA • Anti-dsDNA • ANCA • Anti-GBM antibody • Cryoglobulins
Investigations (other)
• Urine
o Microscopy - check for red cell casts
o 24 hr collection: creatinine clearance and protein
• Imaging
o Renal tract ultrasound to exclude other pathology (e.g. obstruction)
• Renal Biopsy
o For microscopy
• Investigations for associated conditions (e.g. HBV, HCV and HIV serology)
