Glomerulonephritis Flashcards
What is glomerulonephritis ?
- A group of renal diseases which cause immune-mediated disease of the kidneys affecting the glomeruli
- There is disruption of barrier function of the glomerular capillary due to damage to the 3 components which leads to haematuria and/or proteinuria
What are the 3 main cells which can be damaged in glomerularnephritis ?
- endothelial cells
- mesangial cells
- podocytes
How does the cell which is damaged in the nephron help determine the features of the type of glomerularnephritis ?
- If it is damage to the mesangial or endothelial cells this leads to a proliferative lesion and red cells in urine.
- If it is damage to the podocytes this leads to a non-proliferative lesion and protein in urine
How do the cells (referring to the 3 main ones mentioned earlier) differ in their response to being injured?
- Damage to podocytes results in atrophy of the podocytes which results in loss of the membrane barrier in the glomerular capillary which then allows plasma proteins in ==> proteinuria
- Damage to the mesangial cells results in chemokine release and attraction of inflammatory cells
- Damage to endothelial cells results vasculitis (inflam of blood vessels)
Mesangial cells and endothelial cell damage presents similarly – both with haematuria, how would you decide between the two for which cell is most likely to be damaged?
Look at the creatinine – the creatinine in endothelial cell damage will be higher than in mesangial cell damage
How is glomerulonephritis diagnosed ?
CLINICAL PRESENTATION
BLOOD TESTS
EXAMINATION of URINE
- Urinalysis - haematuria, proteinuria
- Urine microsopy - RBC (dysmorphic), RBC & granular casts, lipiduria
- Urine Protein: Creatinine Ratio / 24 hour urine - quantify proteinuria
KIDNEY BIOPSY
What are the clinical presenting features of glomerulonephritis ?
- Haematuria
- Proteinuria
- Urine microscopy - dysmorphic RBC’s
- Impaired renal function - AKI, CKD
- Hypertension
What are the 2 syndromes which different types of glomerulonephritis fall under the category of ?
- Nephrotic syndrome
- Nephritic syndrome
What is nephrotic syndrome indicative of ?
Indicative of a non proliferative process affecting Podocytes
What is nephritic syndrome indicative of ?
Indicative of a proliferative process affecting endothelial cells
What are some of the features which may differentiate a glomerulonephritis from a disease like intersitial nephritis ?
- Possibly normal renal function in the GN
- Look for antibodies
- May see dysmorphic RBC’s in the GN
How are the different types of GN classified ?
As primary (idiopathic)
or
Secondary caused by eg. infections or drugs associated with eg. malignancies or part of systemic disease eg. ANCA - associated systemic vasculitis, lupus, Goodpastures, HSP
How are the different classifications of GN diagnosed ?
Histology:
Take a renal biopsy and then do Light Microscopy/ Immunofluorescence/ EM
What is meant by Proliferative or non-proliferative when classifying GN?
Usually refers to presence or absence of proliferation of mesangial cells
What is meant when GN is described as focal/diffuse?
< or > 50% glomeruli affected
On histological classification of GN what is meant by global or segmental?
All or part glomerulus affected
Describe what is meant by the descriptive term cresentric when describing GN?
Presence of crescents - epithelial cell extracapillary proliferation eg. rapidly progressive glomerulonephritis (RPGN) in vasculitis
What are the principles for treatment of glomerulonephritis ?
- Reduce degree of proteinuria
- Induce remission of nephrotic syndrome
- Preserve long term renal function
What is the treatment of glomerulonephritis ?
- Anti-hypertensive (target BP <130/80 - <125/75 if proteinuria) ACEi or ARB then add diuretic if required to control BP or nephrotic syndrome
- Statin - to reduce CVD risk
- Anticoagulants if nephrotic syndrome
Immunosuppressive therapy:
Drugs
- Corticosteroids (Prednisolone po/MethylPred IV)
- Azathioprine
- Alkylating agents (Cyclophosphamide/ Chlorambucil)
Plasmapharesis (TPE-therapeutic plasma exchange) – trying to remove the antibody causing it
Antibodies: IV Immunoglobulin - Monoclonal T or B cell Antibodies
What is the main potential side effect of immunosuppressive therapy in the treatment of glomerulonephritis due to e.g. cyclophosphamide?
Infection
