Acute kidney injury Flashcards Preview

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Flashcards in Acute kidney injury Deck (62):
1

Is acute kidney injury common?

Yes

2

Mortality increases with increasing severity of AKI. T/F

True

3

Define acute kidney injury (AKI)

Rapid decrease in kidney function characterised by >26.4mmol rise in serum creatinine OR 50% increase creatinine from baseline OR reduction in urine output

4

When is AKI defined?

After fluid resuscitation
After obstruction is excluded

5

Define the stages of AKI

Stage 1 - creatinine rise >26 OR increase 1.5-1.9 reference creatinine
2-2.9 reference creatinine
3 reference creatinine OR increase to >354 OR need for renal replacement therapy

6

Is AKI usually based on urine production or creatinine? Why?

Creatinine
Because urine output is usually poorly measured on wards

7

AKI is a diagnosis. T/F

False - it's a description for which there will be an underlying cause

8

How can you categorise the causes of AKI?

Pre-renal (functional)
Renal (structural)
Post-renal (obstruction)

9

What are some pre-renal causes of AKI?

Hypovolaemia
- haemorrhage
- diarrhoea & vomiting
- burns

Hypotension
- cardiogenic shock
- sepsis
- anaphylaxis

Renal hypoperfusion
- NSAIDs
- ACE/ARB
- hepatorenal syndrome

10

What is hepatorenal syndrome?

Kidney failure as a result of liver failure

11

Define oliguria

12

Is pre-renal AKI reversible?

Volume depletion can be reversed and AKI can recover

13

How does angiotensin II affect the kidney?

Efferent arteriolar vasoconstriction and thus increased kidney BP (hydrostatic capillary pressure) and thus increased GFR

14

How does an ACE inhibitor affect the kidney?

Loss of angiotensin II vasoconstriction and thus no arteriolar constriction (i.e vasodilation) and thus reduced GFR

15

Why might a patient with diarrhoea and vomiting (i.e volume depletion) who is on an ACE inhibitor present with AKI? How is this prevented?

Reduced volume combined with vasodilation from effects of ACEi causes reduced GFR and hence AKI

Tell patients on ACEi/NSAID/Diuretic to stop drugs during periods of diarrhoea and vomiting

16

Explain the pathphysiology of AKI

Volume depletion -->
Decreased intravascular volume -->
RAAS system & ADH increase -->
Salt & water retention -->
Oliguria -->
AKI

17

What happens if pre-renal AKI is missed?

It can lead to acute tubular necrosis

18

What is acute tubular necrosis? What are the common causes?

Histological diagnosis of a type of AKI (commonest form)
Volume depletion
Sepsis
Rhabdomyolisis
Drug toxicity

19

How is pre-renal AKI treated?

Reversal/removal of precipitating factors
- Assess hydration
- Fluid challenge for hypovolaemia
- Supportive

20

How can you assess the hydration status of a patient?

Heart rate
Blood pressure
Urine output
JVP
Cap refill
Peripheral oedema
Pulmonary oedema

21

What types of fluid challenge are indicated in AKI?

Crystalloid (NaCL)
Colloid (gelofusin)

22

Over which level of fluids given, with no clinical improvement, should you seek help?

1000ml

23

How are fluid challenges given?

Give fluid bolus, reassess, repeat as needed

24

Why should dextrose not be given in AKI? Why not hartmans?

It does not go into the intravascular volume
It contains potassium which is not ideal in AKI

25

What are some causes of renal AKI?

Vasculitis
- ANCA associated small vessel - Wegner's, GPA

Glomerulonephritis
- lupus nephritis
- goodpastures
- post infective
- infective endocarditis

Acute tubular necrosis
- rhabdomyelitis
- contrast
- ischaemia
- gentamicin

Acute interstitial nephritis
- antibiotics
- PPI
- NSAIDs
- TB infection
- sarcoidosis

26

Diseases causing inflammation or damage to cells leading to AKI. Which category of AKI does this describe?

Renal

27

How can renal AKI be further subdivided?

Blood vessel
Glomerulus
Tubular disease
Interstitial disease

28

What are the symptoms of AKI?

Uraemic
- Constitutional (anorexia, fatigue, etc)
- Nausea and vomiting
- Itch
Fluid retention
- Fluid overload (oedema, SOB)

29

What are the signs of AKI?

Fluid overload (oedema, hypertension, pulmonary oedema, effusion)
Uraemic (itch, pericarditis)
Oliguria

30

Which points of a history might point towards AKI?

Sore throat
Rash
Joint pain
Diarrhoea and vomiting
Haemoptysis
Drug history
Recent contrast (angiogram, etc)

31

Which clinical results might point towards AKI?

Urinalysis (blood & protein)
Blood results (anaemia, eosinophilia, raised CK)
Vascular bruits

32

Why might sore throat point towards AKI?

Post strep glomerulonephritis

33

Why might haemoptysis point towards AKI?

Goodpastures

34

What are the triple whammy drugs?

Diuretics
NSAID
ACE/ARB

35

Does myeloma cause anaemia?

Yep

36

Haemorrhage can cause anaemia. T/F

True

37

Low calcium and high phosphate points to what?

Vitamin D deficiency perhaps from CKD

38

What might eosinophilia indicated?

Interstitial nephritis (main cause drugs)

39

How can compartment syndrome cause AKI?

Rhabdomyolisis

40

How would you investigate an AKI?

U&E
FBC & coagulation screening
Urinalysis
USS
Immunology
Protein elecrophoresis & bence jones proteinuria (>50 y/o)

41

Hyperkalaemia is a medical emergency. T/F

True

42

Haemolytic uraemic syndrome causes which biochemical derangement?

Low platelets

43

What might abnormal clotting indicate in relation to AKI?

Sepsis and disseminated intravascular clotting

44

Blood and protein in the urine indicate which category of AKI?

Renal

45

How is immunology useful in relation to AKI?

ANA (lupus nephritis)
ANCA (vasculitis)
GBM (goodpastures)

46

What are the urgent and non-urgent indications for renal biopsy?

Urgent - suspected rapidly progressing GN OR positive immunology
Non-urgent - unexplained AKI

47

What are the contra-indications to renal biopsy?

Coagulopathy
Warfarin or aspirin
Hypertension
Hydronephrosis (i.e obstruction0

48

Is you've fluid resuscitated but blood pressure is still low then what is the next step?

Inotrope/vasopressor drugs

49

Should nephrotoxic drugs be stopped? What else?

Yes & anti-nephrotics & avoid nephrotoxic/high potassium antibiotics (trimethoprim, gentamicin, co-tramoxazole)

50

What are the complications of AKI?

Hyperkalaemia
Pulmonary oedema
Severe acidosis (40)

51

What is the pathogenesis of post renal AKI? List the causes

Obstruction causing back pressure & hydronephrosis
Stones
Malignancy
Stricture

52

How is post renal AKI treated?

Catheterisation
Nephrostomy
Ureteric stenting

53

What is hyperkalaemia associated with?

Cardiac arrhythmia

54

What is the normal range for potassium?

3.5-5 (>5.5 is hyperkalaemia --> 6.5 is life threatening)

55

How should hyperkalaemia be assessed once it has been biochemically noted?

ECG
Muscle weakness & tingling

56

How does hyperkalaemia look on an ECG?

Peaked T waves
P waves
Prolonged PR interval
Broad QRS
Sine wave pattern
Bradycardia

57

How is hyperkalaemia managed?

10ml 10% calcium gluconate
Insulin (actarapid) and dextrose
Salbutamol nebuliser
Calcium resonium (NOT in acute setting)

58

What are the indications for haemodialysys?

Hyperkalaemia >7 (or >6.5 and non-responsive to treatment)
Severe acidosis (40 + pericardial effusion/rub

59

How is acidosis treated?

Sodium bicarbonate

60

What is the natural history of AKI?

Complete recovery (most)
Recover with progressive renal failure (5-10%)
No recovery (10-15%)

61

Risk factors for developing AKI?

Elderly
Diabetes
CKD
Co-morbidity (heart failure, liver failure, etc)

62

What is the most common cause of AKI?

Pre-renal causes

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