Acute Kidney Injury

Question 1

what is an acute kidney injury

Answer 1

an abrupt (<48 hrs) reduction in kidney function:

• absolute increase in serum creatinine levels by >26
• increase in creatinine by >50%
• reduction in UO

Question 2

what is stage 1 AKI

Answer 2

increase > 1.5-1.9 x creatinine reference

<0.5ml/kg/hr urine output for >6 hours

Question 3

what is stage 2 AKI

Answer 3

increase >2-2.9 x reference creatinine

<0.5ml/kg/hr urine output for >12 hours

Question 4

what is stage 3 AKI

Answer 4

increase >3 x reference creatinine

or increase to >354

or need for RRT

<0.3ml/kg/hr urine output for >24 hours or no urine output for 12 hours

Question 5

what are some risk factors for AKI

Answer 5

older age 
chronic kidney disease 
diabetes 
cardiac failure 
liver disease 
peripheral vascular disease
previous AKI

Question 6

what are the 3 categories of AKI causes

Answer 6

Pre-renal (eg. change on blood volume to kidneys) 
Renal (structural) 
Post renal (obstruction)

Question 7

what is the most common cause of AKI

Answer 7

Pre-renal

Question 8

what are some pre-renal causes of AKI

Answer 8

Hypovolaemia

• haemorrhage
• volume depletion (burns)

Hypotension

• cardiogenic shock (heart failure)
• distributive shock (sepsis)

Renal hypoperfusion

• NSAIDS
• ACEi/ARBs
• hepatorenal syndrome

Question 9

what does an untreated prerenal AKI lead to

Answer 9

Acute tubular necrosis

Question 10

What is a pre-renal AKI

Answer 10

reversible volume depletion leading to oliguria and increased serum creatinine

Question 11

what are the most common conditions to cause pre-renal AKI

Answer 11

sepsis
severe dehydration
rhabdomyolysis
drug toxicity

Question 12

treatment for pre-renal AKI

Answer 12

asses hydration

• NEWS
• JVP, capillary refit time, oedema

Fluid challenge for hypovolaemia

-normal saline (0.9% NaCl) bolus then reassessment and repeat if necessary

Question 13

what is a renal AKI

Answer 13

disease causing inflammation or damage to cells causing an AKI

Question 14

what are the main types of disease that cause renal AKI

Answer 14

Blood vessel disease
Glomerular disease
Interstitial injury
Tubular injury

Question 15

what diseases affect the renal blood vessels causing AKI

Answer 15

vasculitis 
renovascular disease (atherosclerosis in vessels in kidneys)

Question 16

what glomerular diseases cause renal AKI

Answer 16

glomerulonephritis

Question 17

what interstitial injuries cause renal AKI

Answer 17

Drugs - penicillin, NSAIS, PPIs
Infection - TB
Systemic disease (sarcoidosis)

Question 18

what tubular injuries cause renal AKI

Answer 18

ischaemia (prolonged renal hyper perfusion)
drugs (gentamicin)
contrast
rhabdomyolisis

Question 19

what are the sings/symptoms of renal AKI

Answer 19

anorexia 
weight loss 
fatigue 
lethargy 
nausea and vomiting 
itch, pericarditis (uraemic symptoms) 
fluid overload (oedema, SOB) 
oliguria

Question 20

what clues in the history suggest a renal AKI

Answer 20

rash (lupus or vasculitis) 
sore throat
joint pain (lupus) 
haemoptysis 
drug history 
recent contrast scans 
blood results (suggestive of vasculitis)

Question 21

what type of AKI is it if there is protein and blood in the urine

Answer 21

renal cause of AKI

Question 22

how long after a contrast scan does contrast nephropathy occur

Answer 22

within 72 hours

Question 23

what does eosinophilia suggest

Answer 23

eosinophilic granulomatosis with polyangitis

Question 24

what should you be worried about if patient has come in after lying for a v long time

Answer 24

rhabdomyolysis

Question 25

what investigations are done for renal AKI

Answer 25

Us&Es 
FBC and coagulation screen 
Urinalysis 
USS
Immunology 
Protein electrophoresis

Question 26

treatment for general AKI

Answer 26

establish good perfusion pressure (fluid resuscitate and then vasopressors if needed)

treat underlying causes (antibiotics if sepsis)

stop nephrotoxins

dialysis if patient remains anuric and uraemia

Question 27

what are some life threatening complications of AKI

Answer 27

hyperkalaemia

fluid overload

severe acidosis

ureic pericardial effusion

severe uraemia

Question 28

what is a post renal AKI

Answer 28

AKI due to obstruction of urine flow leading to back pressure (hydronephrosis) and therefore loss of concentrating ability of the kidneys

Question 29

what are some causes of post renal AKI

Answer 29

stone
cancers
strictures
extrinsic pressure

Question 30

what is the treatment for post renal AKI

Answer 30

relieve obstruction

• catheter
• nephrostomy

refer to urology if ureteric stenting required

Question 31

what is hyperkalaemia

Answer 31

life threatening condition of too much K in the blood

associated with cardiac arrhythmia

Question 32

what are the ranges for normal - life threatening hyperkalaemia

Answer 32

normal - 3.5-5
hyperkalaemia >5.5
life threatening hyperkalaemia >6.5

Question 33

how do you treat hyperkalaemia

Answer 33

• Cardiac monitor and IV access
• Protect myocardium (calcium gluconate)
• Move K+ back into cells (insulin with 50ml dextrose, salbutamol nebs)
• Prevent absorption from GI tract (calcium resonium)

Question 34

what gives urgent indication for dialysis

Answer 34

hyperkalaemia >7 or >6.6 but unresponsive to medical therapy

severe acidosis - pH 7.15<

fluid overload

real pericardial rub/effusion

Question 35

what is the mortality rate for AKI alone

Answer 35

10-30%

Question 36

what is the mortality rate for AKI with one other organ dysfunction

Answer 36

30-50%

Question 37

what is the mortality rate for AKI with multi-organ failure

Answer 37

70-90%

Question 38

what percentage of people recover from AKI but have progressive CKD

Answer 38

5-10%

Question 39

Triggers for AKI

Answer 39

hypotension 
hypovolaemia 
sepsis 
deteriorating NEWS 
recent contrast scan 
exposure to certain drugs