Acute Kidney Injury

Question 1

Define Acute Kidney Failure

Answer 1

An abrupt (<48hrs) reduction in kidney function defined as

–an absolute increase in serum creatinine by >26.4µmol/l
–OR increase in creatinine by >50%
–OR a reduction in UO

Can only be applied following adequate fluid resuscitation & exclusion of obstruction

Question 2

what are the classifications of acute kidney injury?

Answer 2

Stage 1- Increase >26µmol/L or Increase > 1.5-1.9 x reference Cr

or urine output < 0.5 mL/kg/hr for > 6 consecutive hrs

Stage 2- Increase > 2 to 2.9 x reference SCr

or urine output <0.5mL/kg/hr for >12 consecutive hours

Stage 3- Increase > 3 x reference SCr or increase to > 354 µmol/L or need for RRT

or <0.3 mL/kg/hr for > 24hrs or 12 hrs for anuria

Question 3

what are the pre-renal causes of acute kidney injury?

Answer 3

• Hypovolaemia
• Haemorrhage
• Volume depletion (e.g. D&V, burns)
• Hypotension
• Cardiogenic shock
• Distributive shock (e.g. sepsis, anaphylaxis)
• Renal Hypoperfusion
• NSAIDs / COX-2
• ACEi / ARBs
• Hepatorenal syndrome

Question 4

untreated pre renal AKI leads to ……

Answer 4

acute tubular necrosis

Question 5

management for pre renal AKI

Answer 5

assess hydration status:

BP

HR

UO

JVP, Oedema, Pulmonary Oedema

cap refill

Give 0.9% IV Saline then reassess

Question 6

list causes of renal AKI

Answer 6

•Vascular

- vasculitis, renovascular disease

•Glomerular
–Glomerulonephritis

Interstitial Nephritis
–Drugs
–Infection (TB)
–Systemic (sarcoid)

Tubular Injury
–Ischaemia—prolonged renal hypoperfusion
–Drugs (gentamicin)
–Contrast
–Rhabdomyolysis

Question 7

what are the life threatening complications of AKI?

Answer 7

• Hyperkalaemia
• Fluid Overload (Pulmonary oedema)
• Severe Acidosis (pH < 7.15)
• Uraemic pericardial effusion
• Severe Uraemia (Ur >40)

Question 8

what is the management of hyperkalaemia?

Answer 8

•Cardiac Monitor & IV access

•Protect myocardium
–10mls 10% calcium gluconate (2-3mins)

•Move K+ back into the cells
–Insulin (actrapid 10units) with 50mls 50% dextrose (30 mins)
–Salbutamol Nebs (90 mins)

•Prevent absorption from GI tract
–Calcium resonium (NOT in the acute setting)

Question 9

what are the indications for acute dialysis?

Answer 9

•Hyperkalaemia
–>7
–>6.5 unresponsive to medical therapy

•Severe Acidosis
–pH < 7.15

• Fluid overload
• Urea >40, pericardial rub/effusion

Question 10

what is the mortality rate of AKI alone

AKI + one other organ dysfunction

AKI + multiple organ failure?

what % recover renal function?

Answer 10

•Mortality
•AKI alone 10-30%
•AKI with one other organ dysfunction 30-50%
•AKI as part of multiorgan failure 70-90%
•
•Recovery of renal function
•10-15% no recovery of renal function
•5-10% recover but have progressive CKD
•Rest recover

Question 11

40 year old male presenting with general malaise & haemoptysis (Urea 28, Creatinine 600, elevated ant-GBM)

Answer 11

Good pasture’s Syndrome

Question 12

25 year old IVDA found collapsed at home

Answer 12

•Rhabdomyolysis

Question 13

. 82 year old man admitted with BP 70 30, T 39, pulse 140bpm, K+ 7.0, urea 48, Cr 789, CRP 250, CXR left basal consolidation

Answer 13

Acute Tubular Necrosis

Question 14

72 year old man presenting with difficulty passing urine and reduced urine output

Answer 14

Obstructive Uropathy

Question 15

•Which of the following drugs do not cause hyperkalaemia?

• A. Spirolonolactone
• B. Ramipril
• C. Amiloride
• D. Furosemide
• E. Atenolol

Answer 15

furosemide

Question 16

• 80 year old male admitted with 4-5 day history of diarrhoea. On admission BP 80 40, pulse 30bpm. Bloods phone back: Na 135, K+ 8.0, Urea 50, Cr 1000, Bicarb 9
• Which of the following drugs would you administer first?
• A. insulin/dextrose
• B. Sodium Bicarbonate
• C. Salbutamol nebuliser
• D. Calcium Resonium
• E. Calcium Gluconate

Answer 16

Calcium Gluconate

Question 17

• Which of the following is not an indication for emergency dialysis?
• A. Pulmonary Oedema (in context of AKI)
• B. Life threatening hyperkalaemia
• C. Uraemic Pericarditis
• D Elevated creatinine > 500
• E Severe Acidosis

Answer 17

elevated creatinine