L12: Acute Renal Failure

Question 1

What is acute kidney injury? (definition)

Answer 1

• rapid decline of renal function
• – if kidneys not working effectively, will have fluid build up in body
• usually a decrease in urine output (oliguria or anuria)
• usually an increase in creatinine levels

Question 2

What 3 values are used to measure kidney function?

Answer 2

1. Creatinine
2. eGFR
3. Urine Output

Question 3

What does eGFR measure/is indicative of?

Answer 3

correlates to kidney function

Question 4

Why is creatinine not a good marker of renal function? Why is it not a useful indicator of acute renal failure?

Answer 4

• is a late marker, observed only with marked damage to functioning nephrons
• creatinine is a by-product of muscle metabolism (more muscle = more creatinine)

Question 5

What is anuria? What is the associated GFR?

Answer 5

Anuria: failure of the kidneys to produce urine

- GFR of 0mL/min

Question 6

What is oliguria? What is the associated GFR?

Answer 6

Oliguria: urine output < 300 mLs in 24 hours

Question 7

The causes of AKI are broadly split into 3 categories which are:

Answer 7

1. Pre-Renal (reduced renal perfusion)
2. Renal (direct injury to kidney)
3. Post-Renal (obstruction)

Question 8

For inpatient AKI, what is the most likely cause?

Answer 8

intra-renal causes

Question 9

For outpatient AKI, what is the most likely cause?

Answer 9

pre-renal causes

Question 10

List some risk factors for AKI

Answer 10

• AGE*
• Chronic Kidney Disease (CKD)
• Heart Failure
• Liver Disease
• Diabetes
• Vascular Disease
• Nephrotoxic Meds

Question 11

List some PRE-RENAL causes of AKI

Answer 11

• Hypotension
• – heart failure
• – dehydration
• – bleeding
• – sepsis
• hepatorenal syndrome
• renal artery stenosis
• renal artery clot

Question 12

List some RENAL causes of AKI

Answer 12

• NSAIDs
• ACE Inhibitors
• Angiotensin II Receptor Blockers
• Gentamicin
• Glomerulonephritis
• Vasculitis
• Interstitial Nephritis

Question 13

List some POST-RENAL causes of AKI

Answer 13

• bladder tumour
• ureter tumour
• prostate enlargement
• renal stones
• pelvic cancer

Question 14

What is the main treatment/management plan for AKI? (“the 4 Ms”)

Answer 14

1. Monitor the Patient
2. Maintain Circulation (prescribe water + salts)
3. Minimize Kidney Insults
4. Manage Acute Illness

Question 15

What is pulmonary-renal syndrome?

Answer 15

Pulmonary Renal Syndrome: diffuse alveolar haemorrhage + glomerulonephritis (usually at the same time)

• – usually always an autoimmune disease
• – e.g. ANCA vasculitis, Goodpasture’s syndrome