LMP301 Lecture 5: Renal Diseases Flashcards
What are the nitrogenous wastes?
- Ammonia
- Urea
- Uric acid
Why must the kidney remove waste?
Protein metabolites from catabolism / diet will accumulate -> toxic effects
Ammonia is waste from…
proteins (AA)
Urea is waste from…
Ammonia
Uric acid is waste from…
Nucleic acids
How is ammonia removed from the body?
Converted to urea
Where does ammonia get converted to urea?
Liver
Besides nitrogenous wastes, what else is secreted from the kidneys?
Creatinine
What is creatinine?
Product of muscle metabolism
“Normal creatinine” levels varies depending on…
Muscle mass
What is the major waste secreted by the kidney?
Urea
GFR
Glomerular Filtration Rate
What is GFR?
Measure of kidney function
What is the most ideal way to measure GFR?
Creatinine clearance
What is creatinine clearance?
Measure how much creatinine passes through the kidneys for 24h -> GFR
How is creatinine clearance carried out?
24h urine sample & creatinine in plasma
What are 2 ways to measure GFR?
- Creatinine clearance
2. Estimation
How is GFR estimated?
1/[plasma creatinine]
What happens at the glomerulous?
Filtration of plasma & small molecules
What happens to the filtrate from the glomerulous?
Goes into tubules
What happens at the tubules?
Reabsorption of water & nutrients back into the blood stream
How much blood goes to the kidney per min?
1200 mL/min
How much filtrate is produced at the kidneys per min?
120 mL/min
GFR is…
The amount of filtrate produced by the kidneys per minute.
What are the 2 types of renal failure?
Acute & chronic
ARF
Acute renal failure
ARF is different from CRF…
Rapid onset and reversible if treated in time
To distinguish between CRF and ARF, we must examine what aspect of renal failure?
How fast the onset was
ARF can commonly found in people who are…
severely ill
Early detection of ARF relies on…
Sequential monitoring of urea & creatinine levels
“Renal function tests” = looking at…
Urea & creatinine levels
Oliguria
less than 400 ml urine / day
What happens to the volume of urine when someone has ARF?
Usually decreases (oliguria or anuric)
What is it called when there is no urine produced at all?
Anuric
< 400 mL urine / day
Oliguria
Why might urine output be not affected sometimes (ARF)?
If renal tubular dysfunction is the main issue
When can ARF take place?
- Pre-renal
- Renal
- Post-renal
“Extrinsic” renal failures refer to problems…
Pre and post renal
“Intrinsic” renal failure refers to problems…
at the kidney (renal)
Pre-renal causes for ARF
Hypovolemia
Hypovolemia is associated with…
Hypotension: insufficient volume of blood getting to the kidneys -> decreased renal blood flow
What will cause hypovolemia?
Injuries with blood or ECF loss
Hypovolemia will cause decreased blood flow to the kidney, which then…
Stimulates aldosterone -> reabsorb Na+ (and water) -> concentrated urine
A urine sample of someone who has ARF due to hypovolemia is likely to be…
- Small volume
- Concentrated
- Low in Na+
How to treat pre-renal causes of ARF?
- Give fluids & electrolytes
2. Osmotic diuretic
If treatment by fluids & electrolytes is not enough, what is given?
Osmotic diuretic
What are the dangers of osmotic diuretic?
If given for renal or post-renal…
Increased filtrate produced has nowhere to go (pressure build-up). This may lead to death by congestive heart failure.
What is the point of osmotic diuretic?
Agent that holds onto water in the blood (increase blood volume) -> increase blood flow to kidney to restore normal function
Renal causes of ARF
- ATN
- Protein deposition in the nephron
- Glomerulonephritis
ATN
Acute tubular necrosis
What is ATN?
Poison / toxin that affects the tubular cells -> tubular cells die
What is protein deposition in the nephron?
Excess of myoglobin & myeloma proteins -> clogs nephrons
Why might there be too much myoglobin and myeloma proteins in the nephron?
- Muscle trauma
- Cancer
What 2 proteins can be found in the nephron to indicate renal disease?
Myoglobin & myeloma
what is glomerulonephritis?
Inflammation of the glomerulous
What are granular casts?
Protein plugs that forms on the inside of tubules and will get flushed out with urine once patient recovers
What can be found in the urine after recovery from renal ARF?
Brown granular casts
What do the granular casts contain?
Protein material
Tubular epithelia cells
Formed elements if bleeding occured
Post-renal causes for ARF
Obstruction (urine has nowhere to go)
Post-renal obstruction can be caused by…
- Injury
- Kidney stones
- Inflammation / swelling
- Tumours
What type of tumours can impact the renal system?
Prostate
Cervix
Bladder
What indicates renal failure on a lab test?
Increased levels of urea & creatinine
In normal kidneys, what happens when there is a rise in blood pressure?
Large increase in Na+ secretion
What is the key cause of advanced renal disease?
Inability to secrete Na+ (and water)
People with advanced renal disease develop…
Volume dependent hypertension
Nephrosclerosis
Degradation of arterial walls in the nephron
Stenosis
Abnormal narrowing of blood vessels
What does prolonged hypertension cause?
Degradation of arteriole walls
What might cause hypertension around the kidneys?
Renal arteries may be narrowed
Prolonged hypertension may will cause destruction of….. which will lead to…
Glomeruli; loss of kidney function
What is the end result of progressive renal damage?
CKD (chronic kidney disease)
CKD
CRF
Chronic kidney disease
Chronic renal failure
Can CKD by reversed?
No, it can only be slowed
How can CKD progression be slowed?
- Decrease protein intake
Slow progression of CKD:
Why does decreasing protein intake help?
Reduce creatinine levels -> reduce GFR -> lessen load on kidneys
Slow progression of CKD:
How can blood pressure be lowered?
ACE inhibitors & ARBs
ARBs
Angiotensin receptor blockers
Function of ARBs
Block renin-AT system -> allow Na+ (and water) to be excreted)
What does CKD eventually lead to?
ESRD
ESRD
End stage renal disease
