AKI

Question 1

AKI: definition

Answer 1

a rapid (within 7 days) and sustained (lasting >24 hours) reduction in renal function resulting in oliguria and a rise in serum urea and creatinine.

Question 2

AKI stage 1

Answer 2

1.5x creatinine rise compared to baseline OR urine output <0.5 ml/kg/hour for 6 hours.

Question 3

AKI: stage 2

Answer 3

Stage 2: creatinine rise of 2x compared to baseline or urine output <0.5 ml/kg/hour for 12 hours.

Question 4

AKI: stage 3

Answer 4

Stage 3: creatinine rise of 3x compared to baseline or urine output <0.3 ml/kg/hour for 24 hours (or anuria for 12 hours) or serum creatinine >354umol/dl

Question 5

AKI: risk factors

Answer 5

Chronic kidney disease
Diabetes with chronic kidney disease
Heart failure
Renal transplant
Age 75 or over
Hypovolaemia
Contrast administration

Question 6

AKI: pre-renal causes (55%)

Answer 6

Shock (hypovolaemic, cardiogenic, or distributive)
Renovascular disease (such as renal artery stenosis).

Question 7

AKI: renal causes (35%)

Answer 7

1. Dysfunction in the glomeruli (as in acute glomerulonephritis)
2. Tubules (as in acute tubular necrosis)
3. Interstitial (as in acute interstitial nephritis)
4. Renal vessels (as in haemolytic uraemia syndrome or vasculitides).

Question 8

AKI: post-renal causes (10%)

Answer 8

Caused by obstruction to urinary outflow
1. Luminal (e.g. a kidney stone)
2. Mural (e.g. a tumour of the urinary tract)
3. Due to external compression (e.g. being prostatic hypertrophy)

Question 9

AKI features

Answer 9

Mostly normal, but can progress to:
Oliguria
fluid overload
Arrhythmias
Uraemia e.g. pericarditis or encephalopathy

Question 10

AKI investigations (main)

Answer 10

U&Es
Urinalysis
ABG
Imaging e.g. renal USS

Question 11

AKI investigations

Answer 11

• Bloods
• Dipstick
• Renal USS

Question 12

Management: AKI

Answer 12

• A to E (inc fluids)
• Medication review

Question 13

Nephrotoxic drugs to stop (NADA)

Answer 13

NSAIDs
Aminoglycosides e.g. gentamicin
Diuretics
ACE inhibitors/ARBs

Question 14

Drugs with increased risk of toxicity in AKI

Answer 14

• Metformin
• Lithium
• Digoxin

Question 15

AKI: indication for dialysis AEIOU

Answer 15

Acidosis (severe metabolic acidosis with pH of less than 7.20)

Electrolyte imbalance (persistent hyperkalaemia of more than 7 mmol

Intoxication (poisoning)

Oedema (refractory pulmonary oedema)

Uraemia (encephalopathy or pericarditis)