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Flashcards in Acute kidney injury Deck (32):
1

What is the definition of acute kidney injury?

An abrupt (<48hrs) reduction in kidney function defined as:
An absolute increase in serum creatinine by >26.4µmol/l

Increase in creatinine by >50%

A reduction in urine output
 

2

What markers are used to stage acute kidney injury?

Createnine

Urine output

3

What is stage 1 acute kidney injury?

Createnine: 

Increase >26µmol/L or

Increase > 1.5-1.9 x reference Cr

 

Urine output:

< 0.5 mL/kg/hr for > 6 consecutive hrs

4

What is the definition of stage 2 acute kidney injury?

Creatinine:

Increase > 2 to 2.9 x reference serum Cr

Urine output:

<0.5ml/hour for > 12 hours

 

5

What is the definition of stage 3 acute kidney injury?

Creatinine (one of):

Increase > 3 x reference serum Cr

Increase to > 354 µmol/L

Need for RRT

 

Urine output:

<0.3 mL/kg/hr for > 24hrs

12 hrs for anuria

6

How can causes of acute kidney injury be classified?

Prerenal

Renal

Postrenal

7

What are the main pre-renal causes of AKI?

Hypovolaemia

Hypoperfusion

Hypotension

8

What can cause hypovolaemia resulting in AKI?

Haemorrhage

Volume depletion (e.g. D&V, burns)
 

9

What can cause hypotension resulting in AKI?

Cardiogenic shock

Distributive shock (e.g. sepsis, anaphylaxis)
 

10

What can cause renal hypoperfusion causing AKI?

NSAIDs / COX-2

ACEi / ARBs
Hepatorenal syndrome
 

11

How do NSAIDs cause hypoperfusion of the kidneys?

Prostaglandin inhibition/vasodilatation inhibition of the efferent arteriole

Essentially compromises the blood supply to the kidney

12

Should patients taking ACEi continue their drugs during episodes of D&V?

No: renal perfusion is going to decrease during D&V due to significant fluid loss, and continuing ACEi may cause a major fall in GFR

13

What pathology can be seen in the kidneys if prerenal AKI is left untreated?

Acute tubular necrosis

14

What is the commonest form of AKI in the hospital?

Acute tubular necrosis

15

What are some of the causes of acute tubular necrosis AKI?

Sepsis
Severe dehydration

Rhabdomyolysis

Drug toxicity

16

How can hydration be assessed?

Clinical observations (BP, HR, UO)

JVP

Capillary Refill Time

Oedema

Pulmonary oedema
 

17

How is hypovolaemia treated?

Fluid challenge

Crystalloid (0.9% NaCl) or Colloid (Gelofusin)

Give bolus of fluid then reassess and repeat as necessary

If >1000mls IN and no improvement, seek help
 

18

What are the four types of causes of AKI?

Vascular

Glomerular

Interstitial nephritis

Tubular injury

19

What are the symptoms of AKI?

Constitutional symptoms:
Anorexia, weight loss, fatigue, lethargy

Nausea & Vomiting

Itch

Fluid overload

Oedema, SOB
 

20

What are the signs of acute kidney injury?

Fluid overload including oedema, pulmonary oedema, effusions (pleural & pulmonary)

Uraemia incl itch, pericarditis

Oliguria
 

21

What initial blood tests would you do if AKI suspected?

U&Es (is potassium high)

FBC and coagulation screen

Urinalysis (proteinuria suggeting active GN)

USS (?Obstruction ?Size)

Immunology (ANA (SLE), ANCA (Vasculitis), GBM (Goodpastures))

Protein electrophoresis & BJP
(?myeloma (everyone over 50yrs))

22

What are the urgent indications for renal biopsy?

Suspected rapidly progressive GN

Positive immunology & AKI 
 

23

What are the semi-urgent indications for renal biopsy?

Unexplained AKI to gain a diagnosis

Rule out obstruction, volume depletion & acute tubular necrosis
 

24

What are the life threatening complications of AKI?

Hyperkalaemia

Fluid Overload (Pulmonary oedema)

Severe Acidosis (pH < 7.15)

Uraemic pericardial effusion

Severe Uraemia (Ur >40)

 

25

What causes post-renal AKI?

Obstruction

26

What is a normal serum potassium level?

3.5-5.0

27

What serum potassium levels define hyperkalaemia and then life-threatening hyperkalaemia?

>5.5

>6.5

28

What are the ECG changes seen in hyperkalaemia?

Tented/large T waves

P-wave flattening

QRS complex widening

VF then ventricular standstill

A image thumb
29

What drug is given in hyperkalaemia to protect the myocardium?

Calcium gluconate

30

Which drugs are given in hyperkalaemia to move potassium back into the cells?

Insulin (actrapid 10units) with 50mls 50% dextrose (30 mins)
Salbutamol nebuliser (90 mins)
 

31

How long are repeated doses of calcium gluconate and insulin dextrose given?

Calcium gluconate until ECG normal

Insulin dextrose until serum potassium normal

32

What are the urgent indications for haemodialysis?

Hyperkalaemia: >7 or >6.5 and unresponsive to therapy

Severe acidosis (<7.15)

 Fluid overload

Urea >40

Pericardial rub/effusion