Pathology of renal disease Flashcards
We filter (fluid)
180 litres per day
We resorb (fluid)
178 litres per day
Urine amount
2 litres per day
How does the kidney work?
Glomerular capillary -blood comes in Interstitium -bigger molecules like red blood cells and albumin too big to pass into interstitium -smaller molecules like urea and creatinine passed through into tubules Tubules (site of most work) -site of resorption -eventually urine comes out
What can go wrong?
Not enough filtration -not enough blood flow -blocked filter -lack of glomeruli Too much filtration -leaky membranes Too little reabsorption -faulty tubules Blocked/ inflamed tubules Tubules die off in chunks Tumours can develop
Blood pressure vs urine output
Blood pressure drops –> urine output drops
Blood pressure increases
–> urine output increases
Low BP for long time –> renal failure
Renal disease - causes of acute renal failure
Lack of blood flow due to haemodynamic shock (bleeding, trauma)
Blocked filter
Leaky filter
Non-functioning tubules
What substances increase in concentration in renal failure?
Urea and creatinine levels in blood
Filter blockage and creatinine
Filter blockage leads to rise in creatitine levels
Causes of a blocked filter
Nothing to see (minimal change) -minimal change glomerulonephritis Proteins (membranous) -deposited in 'filter' -membranous glomerulonephritis Cells (proliferative) -proliferative glomerulonephritis
membranous glomerulonephritis
Membranes are thickened
Deposits of proteins in the glomerulus
Granular kidney post-mortem
Should be smooth
Groups of glomeruli have died off
Down to 30-40% leads to renal failure
Renal disease –> causes of chronic renal failure
Lack of glomeruli -chronic hypertension Blocked filter -chronic glomerulonephritis Non-functioning tubules -tubulointerstitial disease --> crystals or casts
Acute renal failure caused by too much filtreation - leaky membranes/ filters leads to
Proteinuria
-caused by bigger molecules than can usually pass through e.g. albumin
-frothy urine in morning
Test by dipstick in (blood and protein tested)
Too little resorption - Faulty tubules leads to
< reabsorption
> urine
Can lead to acute renal failure
Back to normal in couple of weeks with tubular dialysis