Acute Kidney Injury (AKI)

Question 1

define AKI

Answer 1

abrupt (less than 48 hour) reduction in kidney function due to tubular cell death

Question 2

criteria for AKI

Answer 2

increase in serum creatinine >26.4umol/L
OR increase in creatinine by 50%
OR reduction in UO

Question 3

risk factors for AKI

Answer 3

older
CKD
diabetes
cardiac failure
liver disease
PVD
previous AKI

Question 4

exposure risk factors

Answer 4

hypotension
hypovolaemia
sepsis
recent contrast 
certain medication

Question 5

classification

Answer 5

1. pre-renal
2. renal
3. post-renal

Question 6

causes of pre-renal

Answer 6

hypovolaemia (dehydration, haemorrhage)
hypotension (cardiogenic shock, distributive shock- sepsis, anaphylaxis)
infection (schistosomiasis)
renal hypoperfusion (NSAIDs, COX2, ACEI/ARB and hepatorenal syndrome)

Question 7

what does untreated pre-renal AKI lead to?

Answer 7

acute tubular necrosis

Question 8

tubular necrosis presentation?

Answer 8

muddy brown casts of epithelial cells

Question 9

role of ACEI on the kidney

Answer 9

vasodilation of efferent arteriole which blocks vasoconstriction by angiotensin II

Question 10

diagnosis of pre-renal AKI

Answer 10

assess for hydration (BP, HR, JVP, cap refill, oedema)

fluid challenge for hypovolaemia (crystalloid or colloid, do NOT use dextrose)

Question 11

when to get help in fluid challenge?

Answer 11

> 1000mls and no improvement

Question 12

define renal AKI

Answer 12

inflammation or damage to renal cells

Question 13

causes of renal AKI

Answer 13

• vascular= vasculitis
• glomerular= GN
• interstital nephritis= drugs, infection (TB) and systemic (sarcoid)
• tubular injury= ischaemia, drugs (gentamicin), contrast and rhabdomyolysis

Question 14

define post-renal AKI

Answer 14

obstruction, usually leads to hydronephrosis (usually only affects one kidney)

Question 15

causes of post-renal AKI

Answer 15

stones
cancer
strictures
external pressures

Question 16

management of post-renal AKI

Answer 16

relieve obstruction (catheter, nephrostomy)

Question 17

drugs that cause AKI (DAMN)

Answer 17

diuretics
ACEI/ARB
metformin
NSAIDs

sick day rules= stop if vomiting, diarrhoea or infection

Question 18

presentation of AKI

Answer 18

non-specific= weight loss, fatigue, lethargy
vomiting
breathless (metabolic acidosis or pulmonary oedema)
fluid overload
uraemia (itch, pericarditis)
oliguria

Question 19

diagnosis of AKI

Answer 19

U&Es
FBC and clotting
BP
urinarylsis
USS obstruction
immunology (ANA, ANCA, GBM)
protein electrophoresis and BJP

Question 20

management of AKI

Answer 20

good perfusion= fluid resuscitate (inotropes, vasopressors)
antibiotics if sepsis
dialysis if anuria and uraemia
stop nephrotoxics

Question 21

life-threatening complications of AKI

Answer 21

hyperkalaemia
fluid overload
severe acidosis (pH <7.15)
uraemic pericardial effusion/ severe uraemia

Question 22

what is hyperkalaemia associated with?

Answer 22

cardiac arrhythmias

Question 23

how to diagnosis hyperkalaemia?

Answer 23

ECG

muscle weakness

Question 24

management of hyperkalaemia

Answer 24

• protect myocardium with calcium gluconate
• insulin and salbutamol (move K+ back into cells)
• calcium resonium (NOT in acute setting- GI tract)

Question 25

urgent indications for dialysis

Answer 25

hyperkalaemia (>7)
severe acidosis (pH <7.15)
fluid overload
urea >40 (pericardial effusion/ itch)

consider symptoms and their effects