Session 10

Question 1

Features of acute kidney injury?

How is it defined?

Answer 1

Abrupt decline in GFR
Upset ECF volume and acid/base homeostasis
Accumulation of nitrogenous waste products

Increases serum creatinine by 26.5umol/L within 48 hours
Increase serum creatinine by 1.5 times baseline within 7 days
Urine volume

Question 2

3 causes of acute kidney injury?

Answer 2

Pre renal failure

Intrinsic renal failure

Post renal failure (obstruction)

Question 3

Describe pre renal acute kidney injury

Normal autoregulation in kidney?

Answer 3

GFR reduced due to reduced renal BF. High levels of aldosterone and ADH to try and compensate. AKI if compensatory mechanisms overwhelmed.

If perfusion is low due to high intrarenal prostacylin (prostaglandin) causing vasodilation thus poor perfusion, efferent vasoconstriction will take place to maintain GFR.

If confusing look at session 10 pg 20

Question 4

Causes ofpre-renal AKI? Two subheadings

Answer 4

Impaired renal autoregulation:
Pre glomerular vasoconstriction (sepsis/NSAIDS inhibitng PG’s)
Post glomerular vasodilation (ACEi)

Reduced effective arterial blood volume:
Hypovalaemia(blood loss)
Cardiac failure
Systemic vasodilation (sepsis,cirrhosis,anaphylaxis)

Question 5

Acute tubular necrosis is a type of what?

Causes of ATN?

Pathology?

What are nephrotoxins? Examples?

Answer 5

Intrinsic acute renal failure

Ischaemia,nephrotoxins,sepsis

Cells damaged/necrosis can’t absorb salt/water

Damage epithelial cells lining tubules. End (myoglobin,urate,billi), ex (endotoxin,x ray contrast,NSAIDS)

Question 6

What is rhabdomolyosis?

Issue?

Other intrinsic causes of AKI?

Answer 6

Rapid skeletal muscle breakdown releasing, myoglobin is released into the blood stream.

Myoglobin is a exogenous nephrotoxins

Small vessel disease (vasculitis/thrombotic microangiopathy e.g haemolytic anaemia)
Glomerular disease(lupus nephritis/Anti-GBM/post infection GN)
Acute interstitial nephritis (drugs e.g PPI’s and antiobiotics,infection)

Question 7

What happens in post renal failure to cause AKI?

More common in?

Pathology of post renal?

Answer 7

Obstruction blocking both kidneys or a single functioning kidney.

Elderly

Obstruction (stone) with continual urine production causes raised intraluminal pressure and dilatation of renal pelvis (hydronephrosis) decreasing renal function. Or if further down ureter then hydroureter.

Question 8

In urinalysis when is intrinsic AKI likely?

What type of imaging?

Answer 8

If there is blood/protein in urine

USS, CXR for fluid overload/infection

Session 10 reproductive has the second lecture