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Flashcards in Acute And Chronic Kidney Disease Deck (88)
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1

What is AKI?

Clinical syndrome
Abrupt decline in actual GFR (days to weeks)
Upset of ECF volume, electrolytes and acid-base balance
Accumulation of nitrogenous waste products

2

Why is AKI difficult to diagnose?

Doesn't present with a specific identifiable symptom
Measurements are not massively accurate either

3

What happens to serum creatinine as kidneys decline?

Kidney decline leads to increased serum creatinine

4

How do we define AKI through measurements?

Increased serum creatine > 26.5 micromoles/L within 48 hrs
Increased serum creatinine > 1.5 x their baseline in 7 days
Urine volume <0.5 ml/kg/h for 6 hours

5

Describe the staging of AKI

1 - 3 in increasing severity
1 = 1.5 - 2 times their baseline
2 = 2 - 3 times their baseline
3 = > 3 times their baseline

6

What are the types of AKI?

Pre-renal
Intrinsic renal
Post-renal

7

What are the causes of pre-renal AKI?

Blood supply compromised
Volume depletion
Heart failure
Cirrhosis

8

Give some renal causes of AKI

Renal artery/vein occlusion
Glomerulonephritis
Intrarenal vascular
Ischaemic ATN
Toxic ATN
Interstitial disease
Intrarenal disease
Intrarenal obstruction

9

What does ATN stand for?

Acute tubular necrosis

10

What type of AKI are the vast majority?

Pre-renal

11

90% of intrinsic renal causes of AKI are due to ...

ATN

12

Give some general causes of AKI

Infective
Diarrhoea
Obstetric illness
Venoms
Malaria
Dyes

13

Describe how pre-renal problems cause AKI

Actual GFR reduced due to decreased renal blood flow
No cell drainage
Kidney works hard to restore blood flow
Increased reabsorption of salt and water (lots of aldosterone and ADH)
RAAS activated
Responds to fluid resuscitation

14

Describe autoregulation of the kidneys

Keeps the kidneys between a minimum and maximum BP over which they can maintain a normal perfusion pressure
When hypertensive, these values shift to higher BPs (reset)

15

What is the SM response to decreased renal perfusion?

Vasodilation of afferent
Vasoconstriction of efferent

16

Why do NSAIDs make AKI worse?

Inhibition of production of prostaglandins
Cannot vasodilate in the arterioles of kidneys when required
Cannot regulate perfusion pressure

17

Why can ACEi make AKI worse?

Cannot vasoconstrict when need to

18

Give some causes of reduced ECF volume

Hypovolaemia
Blood loss
Fluid loss
Sepsis
Cirrhosis
Anaphylaxis
LV dysfunction
Valve disease
Tamponade

19

Give some causes of impaired renal autoregulation

Sepsis
Hypercalcaemia
Hepatorenal syndrome
NSAIDs
ACEi
AngII antagonists

20

What are the causes of ATN?

Ischaemia
Nephrotoxins
Sepsis

21

Why is ATN a misnomer?

As there is generally no tubular necrosis
But cells are damaged

22

Describe ATN

Damaged cells cannot reabsorbed salt and water efficiently
Or expel excess water
Aggressive fluid resuscitation risks fluid overload
Lost the ability to concentrate urine therefore urine comes out at the same rate no matter the volume of ECF

23

If dialysis is required, does the mortality of AKI increased or decreased?

Mortality increases

24

Which parts of the nephron are most susceptible to hypoxia?

S3 of PCT
Thick ascending limb LOH

25

Describe damage in the kidneys due to nephrotoxins

Damage the epithelial cells lining the tubules and cause cell death and shedding into the lumen
Can be endogenous or exogenous
ATN more likely if reduced perfusion and a nephrotoxin

26

Give examples of endogenous nephrotoxins

Myoglobin
Urate
Bilirubin

27

In which treatment does urate build up?

Chemotherapy

28

Give some examples of exogenous nephrotoxins

Bacteria endotoxins
Xray contrast
Drugs (ACEi, aminoglycosides, NSAIDs)
Poisons (weedkillers, antifreeze)

29

How does rhabdomylosis cause ATN?

Muscular necrosis releases myoglobin 'crush injury'
In wars and natural disasters
Can occur in drug users and elderly when cannot move
Myoglobin is toxic to tubule cells and can also cause obstruction

30

Describe acute glomerulonephritis

Immune disease affecting the glomeruli
Can be primary or secondary