glomerular disorders Flashcards
what layers are the glomerular filtration barrier made of?
endothelium (of the blood vessels)
glomerular basement membrane
podocytes (epithelium)
what do the mesangial cells do?
maintain the structure of the glomerulus
what is a crescent?
an aggregate of macrophages and epithelial cells in Bowman’s space
what are the different presentations of glomerulonephropathy/ glomerulonephritis? NB these are examples of different presentations not all features are present at the same time
asymptomatic nephrotic syndrome nephritic syndrome rapidly progressing GN macroscopic haematuria chronic GN urine dipstick shows blood and protein in it
what is the triad of nephritic syndrome?
abnormal kidney function
blood and protein ion the urine dipstick
HYPERtension
what are the features of nephrotic syndrome?
- nephrotic range proteinuria where you leak >3g of protein in the urine
- oedema
- low albumin in the blood ie hypoalbuminaemia
- hyperlipidaemia
- may or may not be hypertensive
- kidney function may or may not be abnormal
what is the time over which rapidly progressing GN develops?
2-3 weeks
How does a person with chronic GN present?
with all the stages of CKD
- abnormal kidney function
- anaemic
- bone disease
- blood and protein in the urine dip
- HYPERtension and this progresses over months or years
which is more aggressive, nephrotic or nephritic syndrome?
nephritic due to the hypertension and the abnormal kidney function
what must you see on the urine dipstick to diagnose GN?
blood and protein
what antibody would we be looking for if we suspect vasculitis?
ANCA
what are the small vessel vasculitides affecting the kidney?
granulomatosis with polyangitis (GPA)
microscopic polyangitis (MPA)
renal limited vasculitis - without systemic features
eosinophilic granulomatosis
what are some extra-renal signs associated with ANCA positive vasculitides?
sinusitis epistaxis lung involvement = haemoptysis GI affected - eg PR bleeding skin rash
also constitutional symptoms:
- lethargy
- weakness
- weight loss
which vessels does small vessel vasculitis involve?
capillaries
venules
arterioles
small arteries
How are the subtypes of vasculitis diagnosed?
through the accompanying signs of the vasculitis eg whether other organs are involved etc
what are the investigations that are done for vasculitis?
URINE DIPSTIK
ANCA ie immunology screen
renal biopsy
what is seen on renal biopsy in vasculitis?
- segmental glomerular necrosis
- crescent formation
- fibrosis
- tubular atrophy
when can you get a false positive with ANCA?
in paraneoplastic syndromes
How is vasculitis treated?
induction with steroids and cyclophosphamide and then maintenance immunosuppression with azathioprine
if they have RPGN, treat with plasma exchange
which type of ANCA is found in the majority of cases of Granulomatosis with polyangiitis (GPA)?
c-ANCA ie t he cytoplasmic PR3 ANCA
which which type of ANCA is there more extra-renal manifestations, higher mortality and higher relapse rate?
c-ANCA
what is the gold standard for diagnosis of IgA nephropathy?
renal biopsy - will see IgA deposits eg in mesangium (as well as subendothelial and epithelial)
What is the pathophysiology of IgA nephropathy?
a pt has a mucosal infection eg a cold and produces abnormal IgA that gets trapped in the glomerulus
or due to exaggerated bone marrow IgA immune response to viral or other antigens these deposits induce mesangial cells activation and proliferation
where are the deposits of IgA in the glomerulus?
mesangium
filtration membrane
subendothelial
subepithelial
what is the parietal epithelium of the glomerulus called?
Bowman’s capsule