Acute Kidney Injury + Fluid Balance Flashcards Preview

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Flashcards in Acute Kidney Injury + Fluid Balance Deck (29):
1

how much fluid is in the intravascular space?
interstitial?
intracellular?

3L
9L
30L

2

normal GFR is greater than

90ml/min

3

actions of angiotensin - 2

increase antidiuretic hormone
increase aldosterone
increase thirst
constrict the efferent arteriole

4

what is AKI

significant decrease in GFR (>50%) over a period of hours to days leading to electrolyte, fluid, and acid imbalaance with decreased urine output

5

how much urea is reabsorbed and why

50%
creates concentration gradient for reabsorption

6

how much creatinine is reabsorbed

0%

7

creatinine production is proportional to

muscle mass

8

amount of urine for oliguria vs anuria

oliguric = <400mL/24hours
anuric = <100mL/24 hours

9

how much GFR is lost before creatinine begins to rise?

50%

10

what is pre-renal renal failure? what causes it?

due to decreased renal perfusion
shock (septic, anaphylactic, cardiogenic, hypovolemic)
or drugs (ACEI, NSAIDs)
can lead to ATN

11

how do ACEI and NSAIDs reduce GFR

Ang-II constricts the efferent arteriole
prostaglandins dilate the afferent arteriole

12

what is renal AKI

intrinsice damage done acutely to the kidney parenchyma eg. ATN
usually ischemia related or toxin related

13

managenent of acute tubular necrosis

dialysis to maintain removal of toxins etc
restore circulating volume in diuresis stages to prevent hypovolemia
sodium restriction, potassium restriction
remove nephrotoxic drugs

14

in suspected acute kidney injury, what does STOP stand for

Sepsis
Toxins
Obstruction
Parenchymal insult

15

investigations for AKI

URINALYSIS
renal tract ultrasound
ABGs (pH)
potassium

16

comparing pre-renal to ATN

in pre-renal you can usually still concentrate the urine and reabsorb sodium, will have higher osmolarity in pre-renal

17

at what levels is hyperkalaemia concerning

>6.5

18

relationship between insulin and potassium levels

insulin causes potassium to be taken up into cells, causing hypokalaemia.
lack of insulin causes potassium efflux and hyperkalaemia

19

what is SIADH and what does it cause

syndrome of innapropriate antidiuretic hormone
increases water reabsorption.
resulting hypervolemia often causes dilutional hyponatremia

20

what is diabetes insipidus?
what are the 2 types

lack of ADH leading to polyuria, polydipsia
cranial (no release of ADH)
nephrogenic (ADH doesnt work)

21

common cause of nephrogenic diabetes insipidus

lithium toxicity in bipolar

22

extracellular volume mirrors (sodium) content

sodium

23

how can we estimate intracellular volume

with sodium concentration
hyponatremia -> high intracellular volume
hypernatremia -> low intracellular volume

24

adding 3L isotonic saline will increase extracellular fluid or intracellular fluid?

extracellular
the concentration of sodium will be unchanged so intracellular will be unchanged

25

adding 3L of water to a patient will increase extracellular or intracellular fluid?

it will increase both
1/3 will say extracelllar
2/3 intracellular due to the dilutional hyponatremia

26

addition or loss of sodium rich fluid will affect which compartment (intra or extracellular)

extracellular

27

addition or loss of water will affect which compartment (intra or extracellular)

2/3 from intracellular
1/3 from extracellular

28

why cant you correct chronic hyponatremia too quickly?

neurons make their own osmoles to maintain cell size. restoring sodium will cause the cells to shrink quickly. causes myelitis

29

normal potassium

3.5-5mmol/L