L09a: Acute Kidney Injury

Question 1

What is acute kidney injury

Answer 1

A rapid (hours to days) decline in kidney function

Question 2

What do we measure to look at acute kidney injury

Answer 2

Serum creatinine levels

Urine output

Question 3

Can we use estimated GFR to look at acute kidney injury

Answer 3

No

Question 4

Why can we not look at estimated GFR

Answer 4

Estimated GFR only works with people stable kidney disease

Question 5

How many stages of acute kidney injury is there

Answer 5

3

Question 6

Which stage is the worst acute kidney injury

Answer 6

Stage 3

Question 7

What happens to creatinine levels as the stages of acute kidney injury increase

Answer 7

Serum Creatinine levels increase

Question 8

What happens to the urine output as stages of acute kidney injury increase

Answer 8

Urine output decreases

Question 9

What are the main categories of causes of AKI

Answer 9

Pre-renal
Renal
Post renal

Question 10

What is pre-renal causes about

Answer 10

Perfusion of the kidney

Question 11

What is renal causes of about

Answer 11

Kidney disease within the kidney

Question 12

What is the post renal causes about

Answer 12

Obstruction of the urinary tract

Question 13

Why can people get perfusion failure due to

Answer 13

Hypotension
Hypovolaemia (low blood volume)
Haemorrhage
Renal artery occlusion

Question 14

Which drugs make perfusion failure worse

Answer 14

RAAS blockade
NSAIDS
Anti hypertensives
Diuretics

Question 15

What is renal auto regulation

Answer 15

The maintenance of blood flow despite the changes of blood pressure within a given range

Question 16

What happens to the blood flow when blood pressure decreases beyond the auto regulation range

Answer 16

Blood flow decreases

Question 17

Describe the mechanism of the RAAS in low blood pressure/ low blood volume

Answer 17

1) macula densa cells detect low sodium
2) signal is sent to the JGA cells to release renin
3) renin converts angiotensinogen to angiotensin 1
4) ACE converts angiotensin 1 to angiotensin 2
5) angiotensin 2 causes the release of aldosterone form the adrenal cortex
6) aldosterone increases the insertion of sodium eNac channels to increase sodium reabsorption in the collecting duct
7) water follows sodium so blood levels rise
8) angiotensin 2 causes vasoconstriction of blood vessels which also causes a rise in blood pressure

Question 18

What type of drug can block renin

Answer 18

Renin inhibitors

Question 19

What type of drug can inhibit the conversion of angiotensin 1 to 2

Answer 19

Ace inhibitors

Question 20

What type of drug can block the action of angiotensin 2 on the blood vessels

Answer 20

Angiotensin 1 receptor antagonist

Question 21

What type of drug can block the action of aldosterone

Answer 21

Mineralocorticoid receptor antagonist

Question 22

Therefore when the patient uses drugs that block the RAS what do they get

Answer 22

Perfusion failure because they cannot rise the pressure and the pressure goes below the autoregulation range

Question 23

How do we treat perfusion failure

Answer 23

Stop RAS blocking drugs
Give blood / fluid replacement
Blood pressure support
Stop NSAIDs

Question 24

How can we have obstruction in acute kidney injury

Answer 24

Stones
Tumours
Fibrosis
Benign prostate

Question 25

What is the treatment of obstruction

Answer 25

Remove or bypass the obstruction

Question 26

What are the causes of renal disease

Answer 26

Disease that damage the nephron 
Systemic disease: inflammation 
Infection 
Allergic 
Drug toxicity 
Glomerulonephritis

Question 27

What is the treatment for inflammatory renal disease

Answer 27

Steroids
Cyclophosphamide
Plasma exchange
Azathioprine