Hughes - Fluid and Electrolytes Part 1 Flashcards

1
Q

body water composition decreases as ____ increases

A

adipose tissue

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2
Q

2/3 of water is ______
(intracellular or extracellular)

A

intracellular

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3
Q

the 1/3 of water that is extracellular – breakdown where it’s located

A

70% is intertitial and 30% is intravascular

so very small portion is actually in the vessels

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4
Q

3 major INTRAcellular ions

A

potassium
magnesium
phosphate

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5
Q

3 major EXTRAcellular ions

A

sodium
chloride
bicarbonate

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6
Q

water moves from ___ ti ___ osmolality
recap what osmolality is

A

low to high

particles/kg of water

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7
Q

all body fluids are maintained between ___-___mOsm/kg

A

280-295

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8
Q

the kidney is able to regulate osmolality through the activity of….

A

ADH

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9
Q

TRUE OR FALSE

decreased plasma tonicity causes an increase in ADH

A

FALSE - decrease

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10
Q

increased plasma tonicity causes a ___ in ADH

explain what happens

A

increase

more low-solute water will be retained in the body, and thus the urine will be more concentrated

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11
Q

kidney regulates volume through the movement of ____

A

aldosterone

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12
Q

what is the main extracellular osmol

A

sodium

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13
Q

what does entresto do to natriuretic peptide levels

A

increases them by preventing their breakdown

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14
Q

true or false

if a patient is literally visually blown up with fluid, they cannot be hypovolemic

A

FALSE - they can be – can still be hypovolemic intravascularly

whole body vs intravascular are different things

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15
Q

pt gets DVT in leg and it is swelling

are they hypervolemic?

A

NO

can be hypovolemic bc the fludi that’s supposed to be in the vessels is going to a compartment where it’s not supposed to be

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16
Q

the symptoms that occur from hypovolemia occur bc of what 2 things

A

-the underlying cause (ie - vomiting)

-decreased perfusion (fatigue, thirst, etc)

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17
Q

another name for hypervolemia

A

edema

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18
Q

3 things that can cause hypervolemia (edema)

A

increased renal sodium retention

hypoalbuminemia

increased capillary pressure (due to sepsis, trauma, etc)

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19
Q

orthopnea meaning

A

shortness of breath when lying down but improves when you sit up

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20
Q

name 3 cases of “hypervolemia” and what the symptoms would be

A

pulmonary edema - SOB, orthopnea

peripheral edema- swollen legs

ascites - (peritoneal cavity filled w fluid) - abdominal distention, dullness, SOB

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21
Q

symptoms of HYPERVOLEMIA are due to what 2 things

A

-the underlying cause (anuria from renal disease)

-where the fluid is

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22
Q

the more ______ the electrolyte abnormality, the more severe the signs and symptoms will be

A

ACUTE - ie - if sodium changes drastically in 1 day vs slowly over a long time

(also, the further out of range)

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23
Q

hyponatremia technically means….

explain how this can be complicated

A

low ratio of
total body sodium: total body water

if someone drinks more than 16 L a day (the most a kidney can excrete), the sodium can get diluted and appear low, even tho the level is normal

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24
Q

the clinical presentation for hyponatremia is mainly ____ effects

how?

A

NEUROLOGIC

because fluid shifts through the BBB – cerebral edema

if sodium gets very low (110-115) — can cause seizure and coma!!!!!!

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25
Q

as mentioned, hyponatremia can cause neurologic effects because water rushes through the BBB, causing cerebral edema

the brain adapts to this fluid within only a couple days. therefore….

A

we have to correct the sodium EXTREMELY SLOWLY – not too fast

no faster than 4-8 mEq in 24 hours

otherwise, can get CNS effects like behavioral changes, seizures, osmotic demyelination — brain shrinks – lot of damage – potential irreversible

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26
Q

treatment for hypovolemic hypotonic hyponatremia

A

replacement with IV normal saline is ideal – bc as the volume comes back, the kidneys will regain their function and be able to remove the sodium on their own

for mild cases, even just oral replacement solutions can be used (NOT water or gatorade - use pedialyte!!! need glucose AND electrolytes)

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27
Q

goal correction rate for hypotonic hypovolemic hyponatremia

A

4-8mEq/L/hour

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28
Q

treatment for HYPERVOLEMIC hypotonic hyponatremia

A

DO NOT GIVE IV FLUIDS!!!

reduce oral fluid intake, allow for some sodium (if bc of heart failure - not too high) in the diet, and use loop diuretics

(can also use vaptans)

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29
Q

3 potential causes of hypervolemic hypotonic hyponatremia

A

heart failure
nephrotic syndrome
cirrhosis

30
Q

euvolemic hypotonic hyponatremia

likely due to what?

A

hypothyroidism, cortisol deficiency, SIADH (syndrome of inappropriate ADH secretion)

31
Q

as mentioned, a main cause of euvolemic hyponatremia is SIADH

what are the causes of this?

explain what SIADH is

A

lot of causes – cancer, pain, nausea, CNS disease, and a LOT of drugs can cause it

too much ADH is produced and the body, the body will retain water which dilutes sodium - causes hyponatremia

32
Q

treatment for euvolemic hyponatremia

A

correct cause (remove offending drug)
RESTRICT fluid intake

potential drugs —

-loop diuretic
-conivaptan (vaprisol)
-tolvaptan
-sodium chloride tablets
-hypertonic saline

demeclocycline, lithium (not really used

33
Q

true or false

in cases of euvolemia hyponatremia, we want to give IV fluids

A

FALSE

restrict fluids. – may do the job on its own and might not need drugs

34
Q

how does a loop diuretic work to treat euvolemic hyponatremia

A

gets rid of more fluid (without concentrating it)

35
Q

route administration conivaptan

what is brand name?

A

IV only — only used in ICU

brand is Vaprisol

36
Q

differentiate between the MOA of conivaptan and tolvaptan

A

both inhibit vasopressin (ADH) at the V2 receptor and the V1A receptor

HOWEVER

tolvaptan is much more selective for the V2 receptor, and thus has less vasodilation effects

37
Q

CrCl in which conivaptan and tolvaptan should not be used

A

conivaptan - no less than 30mL/min

tolvaptan - no less than 10mL/min

38
Q

conivaptan and tolivaptan are contraindicated when

A

in cases of anuria!! patient needs to be able to pee to get rid of the excess fluid that will be produced by blocking ADH

also contraindicated with strong CYP inhibitors, and tolvaptan contraindicated in hypovolemia

39
Q

how is tolvaptan administered

big concern with is

A

PO

DO NOT CORRECT TOO QUICKLY !! (more than 12MeQ in 24 hours) – osmotic demyelination

also very expensive

40
Q

as mentioned, hypertonic saline (3%) can be used to treat euvolemic hyponatremia

what is a concern and how should it be administerd

A

dont overcorrect!!!!!

also, give via central line bc peripheral line irritating

41
Q

true or false

normal saline can be used to treat euvolemic hyponatremia

A

FALSE - need hypertonic

42
Q

1 gram of sodium chloride tablets = ___ mEq

A

17

43
Q

true or false

demeclocycline and lithium are first line for euvolemic hyponatremia

A

FALSE

2nd line if anything - not really used

44
Q

which class of diuretics is a common inducer of hyponatremia

A

thiazides

NOT LOOPS!

45
Q

true or false

loop diuretics can induce hyponatremia

A

FALSE - thiazides can, but not loops

46
Q

explain how thiazides can induce hyponatremia

A

they cause a decrease in water and sodium reabsorption

this low volume of fluid in the body triggers the release of ADH – which increases the reabsorption of WATER in the collecting tubules

47
Q

4 things that can make a patient prone to thiazide-induced hyponatremia

A

elderly
high doses
dietary sodium restriction
drinking too much water

48
Q

“hypernatremia” technically means a high ratio of ___:___

A

body sodium:body water

49
Q

true or false

hypernatremia is much more rare than hyponatremia

A

TRUE

hypernatremia really only occurs if the thirst center of the brain is damaged

50
Q

true or false

unlike with correcting hyponatremia, when correcting hypernatremia we want to correct as QUICKLY AS POSSIBLE

A

FALSE

SLOWLY - still the risk of osmotic demyelination and permanent brain damage – lethargy, weakness, twitching, irritability, etc

51
Q

explain the treatment for hypernatremia

A

of course - correct the cause

replace fluid deficit:
-if the pt is hypotensive/hypovolemic/shock – use NORMAL SALINE to correct the volume, then correct with sodium

-can use D5W or 0.45% normal saline if the actual total body sodium is also low

52
Q

98% of potassium is located where

A

in the INTRACELLULAR compartment (mainly muscle)

53
Q

how are potassium levels normally maintained in the body

A

by the sodium/potassium ATPase pump

this is controlled by the KIDNEYS – they eliminate the ingested potassium and also maintain the potassium shift between the extra and intracellular compartments

54
Q

true or false

aldosterone decreases the elimination of potassium

A

FALSE - increases elimination

55
Q

name some things that affect the intracellular shift of potassium

A

insulin
B-agonists
A-agonists
pH
exercise

56
Q

name 3 general causes of hypokalemia

A

low intake (dietary)
increased intracellular uptake
excessive loss

57
Q

name 2 drugs that increase the intracellular uptake of potassium

would these drugs thus cause hyperkalemia or hypokalemia

A

beta agonists and insulin

HYPOKALEMIA

bc moving INTRACELLULARLY and by “hypokalemia” we mean the concentration in the blood

58
Q

can loop diuretics cause hypokalemia?
what about thiazides?

A

yes - both can

59
Q

briefly explain what happens as potassium levels get lower and lower in the blood

A

at 1st - asymptomatic – possible malaise and fever

as it gets lower, the heart rate starts to be affected and you can get cramps in the muscles

CPK and AST are elevated, and at LOWEST LEVELS - rhabdomyolysis occurs (less than 2 mEq/L)

60
Q

CHRONIC effects of hypokalemia (name 2)

A

decreased insulin secretion (and thus increased blood glucose)

increased renal ammonia formation (hepatic encephalopathy)

61
Q

is hypokalemia diagnosed by symptoms?

A

no
the symptoms the patient presents with can be from so many different things. therefore, it is diagnosed by a BMP

62
Q

3 general treatments for hypokalemia

A

-correct the cause
-replete the fluid and electrolytes

-hold any medications that may be predisposing them to hypokalemia

63
Q

when a patient has hypokalemia, they almost always have…….

A

hypomagnesium

64
Q

potassium levels are 3-4mEq/L

how much does it take to correct by 0.1mEq/mL??

what if potassium levels are LESS THAN 3

A

20mEq per 0.1Meq increase

so to go from 3-3.5 it would take 100mEq

it takes more like 20-40mEq per 0.1mEq increase in the blood

65
Q

when correcting potassium, it’s very important to….

A

monitor carefully!!!

serum potassium doesnt always reflect the total body potassium

66
Q

which route of administration is preferred for treating hypokalemia

A

oral is preferred over IV

67
Q

patient counseling point when they’re given oral potassium for hypokalemia

A

take with fluid and a glass of water

bc can cause GI issues like NVD, bleeding and perforation

68
Q

oral potassium should be avoided in who

A

patients with impaired gastric motility – can sit there in the GI tract for too long and cause perforation

therefore, should also avoid drugs that slow the GI tract like benadryl - causes bleed

69
Q

true or false

unlike for sodium correction, overcorrection is not a concern for potassium

A

FALSE - IT IS STILL VERY MUCH A CONCERN

overcorrection can cause a life-threatening arrythmia

70
Q

IV potassium rate of administration, and how this changes if the patient presents with a life threatening arrythmia

A

DO NOT OVERCORRECT

generally it’s 40mEq/L - no faster than 10mEq/hour

if the pt has a critical arrythmia - can give 60mEq at 40mEq/hour

71
Q

true or false

giving IV potassium is not preferred. one of the reasons is that it can cause phlebitis

A

TRUE

72
Q
A