Glomerulonephritis Flashcards
acute vs chronic glomerulonephritis?
acute = treatable cause of acute renal failure chronic = 2nd commonest cause of ESRF (after diabetes)
what is glomerulonephritis?
immune-mediated disease of the kidneys affecting the glomeruli with secondary tubulointerstitial damage
describe pathogenesis of GN
humoral/antibody mediated
- intrinsic or planted antigen
- deposition of circulating immune complexes
results in activation and up-regulation of T cells
inflammation results
what is the mesangium?
packing cells making up space between capillaries
barrier between capillary and bowmans space is selective to what?
size and charge selective
GN = disruption of this barrier leading to haematuria and/or proteinuria
how does site and type of injury determine type of urine presentation?
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podocyte damage?
damage to podocyte causes finger projections to shrink back leaving capillary uncovered with big gaps
proteins can therefore leak out
mesangium damage?
mesangium damage causes proliferation, release of angiotensin 2 and chemokines and attracts inflammatory cells
what does damage to capillary endothelium lead to?
vasculitis
blood an protein on dipstick
slight hypertension
normal creatinine
what cell is damaged?
mesangial cells
examination of GN?
urinalysis - haematuria, proteinuria
urine microscopy - RBC, RBC and granular casts, lipiduria
urine protein:creatinine ratio/24 hr urine collection to quantify proteinuria
kidney biopsy
how might haematuria present?
can have achy pain in kidney/loin area
asymptomatic microscopic haematuria
episodes of painless macroscopic haematuria
should be painless but can sometimes be achy
types of proteinuria?
microalbuminuria (30-300mg/day) asymptomatic proteinuria (<1g per day) heavy proteinuria (1-3g/day) nephrotic syndrome (>3g per day)
what are red cell casts and what are they pathopneumonic for?
red cells held together by tubular protein forming gel like cast around them
pathopneumonic of glomerular bleeding
what is nephritic syndrome?
acute renal failure
oliguria
bit of oedema/fluid retention (just due to not peeing)
hypertension
active urinary sediment (lots of RBC, WCCs and granular casts)
happens due to proliferative process affecting endothelial cells
what is nephrotic syndrome?
>3g proteinuria per day hypoalbuminuria (<30) oedema hypercholesterolaemia usually normal renal function indicates a non-proliferative process affecting the podocytes
complicaitons of nephrotic syndrome?
infections (antibodies etc lost in fluid which goes out of vessels)
- e.g cellulitis due to fluid in tissue
renal vein thrombosis
pulmonary emboli (oedema compresses vein in leg causing DVT > PE)
volume depletion (can occur due to overuse of diuretics during treatment)
Vit D deficiency
subclinical hypothyroidism
GN vs non glomerular disease like interstitial nephritis?
only get blood in urine in glomerular disease
2 main causes of GN?
most common = idiopathic
can be caused by infections/drugs
associated with malignancy
can be part of systemic disease (vasculitis, lupus, goodpastures, HSP etc)
histological classification of GN?
proliferative/non-prolferative (usually refers to proliferation of mesangial cells)
focal/diffuse ( 50% of glomeruli affected)
global/segmental (all or part of glomerulus affected)
crescentric (presence of crescents -epithelial cell extracapillary proliferation)
treatment aims of GN treatment?
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2 types of GN treatment?
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non-immunosuppressive GN treatment?
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immunosuppressive treatment of GN?
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general management of nephrotic patients?
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treatment aim of nephrotic patients?
immunosuppression inducing sustained remission
- complete remission = <300mg/day
- partial remission = <3 protein/day
risks of immunosuppressing a nephrotic patient?
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main types of primary idiopathic GN?
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what causes minima change disease?
damage to podocyte causing nephrotic syndrome due to circulating antibody directed to part of the podocyte
most common cause of nephrotic syndrome in children
how is minimal change disease managed?
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responds well to steroids
what is FSGS?
FOCAL SEGMENTAL GLOMERULOSCLEROSIS
focal (only some glomeruli affected with segmental sclerosis)
FSGS vs minimal change disease
tries to repair itself with migration of epithelium to repair the hole in glomerular capillary wall
causes defective repair mechanism and leads to sclerosis
both respond to steroids and immunosuppression
what is membranous nephropathy?
2nd commonest cause of nephrotic syndrome in adults
caused by presence of anti PLA2r antibody which sticks to podocytes forming immune complex outside glomerular capillary wall
what is IgA nephropathy?
commonest GN in the world
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what causes IgG nephropathy?
increased circulating IgA1 (abnormal IgA in sufferers)
production of anti IgA1 antibodies during infection which attacks IgA1 (molecular mimicry, body thinks abnormal IgA is also foreign)
immune complexes form in the circulation
immune complexes form in situ
immune complexes in the mesangium cause local inflammation and injury
what is RPGN?
rapidly progressive glomerulonephritis
rapid deterioration in renal function over days/weeks causing active urinart sediment and glomerular crescents on biopsy
can be part of systemic disease
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what happens in RPGN?
cells burst out of the capillary endothelium
increases pressure in bowmans capsule, compressing the capillaries
leads to ischaemia and death of the glomerulus????????
what is goodpastures?
IgG antibody against glomerular basement membrane
how is RPGN managed?
strong immunosuppression
- steroids
- cytotoxics (cyclophosphamide/mycophenolate/azathioprine)
plasmapheresis
74 year old woman hypoxic haemoptysis creatinine 430 blood and protein on dip red cell casts on microscopy purpuric rash what cells are most likely affected and what test should be done?
endothelial cell injury
ANCA positive vasculitis
ANCA test
