L7: Kidney disease and renal failure Flashcards
3 categorises of kidney disease
pre-renal
intrinsic
post-renal
what does post-renal lead to in the kidney
hydronephrosis
can nephrons regenerate
NO
urinary excretion rate=
filtration rate - reabsorption rate + secretion rate
3 layers of glomerular capillaries
endothelium
basement membrane
podocytes
how does glomerular filtrate move through the podocytes
through slit pores between them
apart from the basement membrane what can also stop protein passage
the podocytes also have a negative charge
main consequence of nephrotic syndrome
protein loss
4 features of nephrotic syndrome
peripheral oedema
proteinuria
hypoalbuminaemia
hypercholesterolaemia
what biochemical markers are needed for a nephrotic syndrome diagnosis
proteinuria
hypoalbuminaemia
what is nephrotic range proteinuria almost always due to
glomerular disease
what are most nephrotic diseases associated with
podocyte injury and loss of anionic charge in the capillary wall
what 2 things does proteinuria result from
loss of charge and size selectivity
2 mechanisms for oedema in nephrotic syndrome
overfill and underfill mechanism
underfill mechanism=
- reduced oncotic pressure means fluid moves into ECF
- reduced plasma volume activates sodium and water reabsorption
what is the overfill mechanism
a defect in sodium excretion increases blood volume increasing hydrostatic pressure moving fluid into ECF
3 primary causes of nephrotic disease
minimal change disease
focal segmental glomerulosclerosis
membranous GN
what is minimal change disease
- effacement of pedicles causing protein leakage
- little chronic damage
treatment of minimal change disease
steroids
what is segmental glomerulosclerosis
- segmental scarring lesions within glomerular tuft
- bad prognosis (hard to treat)
membranous nephropathy
electron dense immune deposits on basement membrane creating holes
in whom are secondary causes of nephrotic disease more common
adults
in whom are primary causes of nephrotic disease more common
children
name 4 secondary causes of nephrotic disease
diabetic nephropathy
amyloidosis
chronic viral infection
cancer
main feature of nephritic syndrome
haematuria
5 features of nephritic syndrome
haematuria small amount of proteinuria mild hyertension oliguria possible oedema
in nephritic syndrome what is the oedema secondary to
oliguria
3 causes of nephritic syndrome in children
haemolytic uraemic syndrome
Henoch-schonlein purpura
post-streptococcal GN
3 causes of nephritic syndrome in adults
goodpasture’s
ANCA- associated vasculitis
primary or secondary mesangiocapillary GN
2 pathways of membrane attack
classic
alternative
what is the classic pathway characterised by
antigen-antibody complex
what activates the classic pathway
Fc portion on the antigen-antibody complex
what does the antigen-antibody complex trigger to cause membrane attack
complement
what does the alternative pathway not depend on
antibody-antigen complexes
what can activate the classic pathway (4)
enzymes
endotoxins
cell membrane
viruses
what can activate the alternative pathway (4)
venom
aggregated Ig
yeast cell wall
bacterial endotoxins
what is MAC
membrane attack complex
what happens to MAC
its inserted into the lipid bilayer leading to movement of ions and water across the membrane leading to cell lysis
in what disease can immune complex trapping happen
lupus
what happens in immune complex trapping
immune complexes present in blood get stuck on basement membrane activating complement
in what disease is the antigen already present in the basement membrane
goodpastures disease
what damage occurs in the basement membrane in goodpastures disease
alpha 3 chain collagen is damaged
in what disease can the antigen be implanted
post infectious GN
what happens in post infectious GN
bacterial antigen implanted in basement membrane causing circulating antibody to bind
what happens in diarrhoea + HUS ( haemolytic uraemic syndrome)
certain endotoxins activate complement (can be through classical or alternative pathway)
who is vasculitis seen in and when
adults in winter season
what causes damage to the kidney in vasculitis
anti-neutrophil cytoplasmic antibodies
what is acute kidney failure
sudden decline in renal function over hrs or days
to cause acute renal failure what does the insult need to be
bilateral
what is acute on chronic renal failure
sudden decline in renal function with CKD background
presentation of acute renal injury
oliguria/ anuria
azotaemia
azotaemia=
high levels of nitrogen containing compounds
3 causes of acute renal injury
glomerular injury
interstitial injury
acute tubular necrosis
what part of the kidney does diabetes type 1 damage
glomerular injury
3 pre-renal causes of kidney damage
sepsis
heart failure
dehydration
2 post renal causes of kidney damage
tumour
stones
3 intrarenal causes of kidney damage
glomerular injury
tubulo-interstitial injury
vascular injury
in CKD what stage do symptoms develop
after stage 4 (GFR <15-29ml/min)
normal kidney function (A wet bed)
-acid base balance
-water balance
-electrolyte balance
-toxin removal
-Blood pressure
-EPO
vit D
3 symptoms of Na/sodium retention
hypertension
oedema
raised JVP
why are patients with CKD prone to gout
high uric acid
