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AAW - CRRAB 2 - week 4 > Tuesday Na and K > Flashcards

Tuesday Na and K Flashcards

1
Q

normal body stores of K

how much can the kidney get rid of in a day at max?

A

3000 to 4000 meq

(50 - 55 meq per kg)

98% is intracellular

kidney can get rid of like 400 meq/day max

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2
Q

if you are seeing a dialysis patient with weak legs what do you think

A

kigh K

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3
Q

EKG changes of hypokalemia

A

DISCLAIMER: THIS WAS MY WAY OF REMEMBERING IT, IT MAY NOT BE 100% ACCURATE FOR PR INTERVAL PROLONGATION

PR interval prolongation (hypokalemia -> bigger gradient of K on the inside of the cell compared to the outside (it’s like as if your Na/K pump is working TOO well) -> increased membrane potential -> takes longer to depolarize -> signal takes longer to travel from atria to ventricles)

ST depression (as a result of increased membrane potential)

Flattened or inverted T wave

U - wave (due to repolarization of the septum as a different time that the ventricular wall. slower depolarization may cause this) (U OK? -> U waves with hypOKalemia)

QRS widening (similar reason as PR elongation)

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4
Q

EKG changes of hyperkalemia

A

PR prolongation

elevated T waves

widened QRS

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5
Q

when are you fucked

A

when you are hyperkalemic and then get a metabolic acidosis

because the way you get rid of H+ is by antiporting it with K+

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6
Q

loop diuretics do what to potassium

A

block NKCC, cause you to excrete more

get hypokalemia

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7
Q

where is aldosterone made in the body

A

adrenal cortex

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8
Q

chronic hypokalemia does what to the kidneys

A

interstitial fibrosis

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9
Q

increasing catecholamines/beta agonists will do what to your potassium

A

cause hypokalemia

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10
Q

metabolic alkylosis due to vomiting can do what to your potassium levels

A

can cause COMPENSATORY hypokalemia

compensatory holding onto H+, the K+/H+ antiporter wastes all your K

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11
Q

if you have more “distal flow” in the kidney, what is going to happen to your potassium?

A

hypokalemia

more distal flow means you absorbed less in the proximal tubule, where you absorb with NKCC pumps

(loop diuretics would cause increased distal flow and hypokalemia)

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12
Q

Eating what would cause hypokalemia in someone who is on a loop diuretic

A

eating more salt.

you would get even more distal flow and then the Na would be sucked up in the distal region and the potassium would be excreted even MORE

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13
Q

having low magnesium does what to your K and how

A

it causes hypokalemia

magnesium normally inhibits ROMK channels.

no Mg and you potassium spills out (can be aggrivated by intake of sodium)

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14
Q

metabolic acidosis due to diarrhea/laxative can do what to your potassium levels

A

causes PRIMARY hypokalemia

K+ follows HCO3- out of the GI tract when you poop

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15
Q

which can cause rhabdo - hyper or hypokalemia

A

hypo

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16
Q

insulin will take up potassium into the cells. what else does this?

A

catacholamines (that work on beta- adrenergic receptors)

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17
Q

Three main causes of increase in serum K if total body K is normal

A

muscle or tissue breakdown
insulin deficiency with hyperglycemia
metabolic acidosis

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18
Q

common drug that can cause high potassium

A

ace inhibitors (lack of aldosterone causes the Na/K antiporter to stop)

19
Q

what do NSAIDs do to you aldosterone levels?

A

NSAIDS block prostaglandin

prostaglandins cause the juxtaglomerular cells lining the afferent arterioles to release renin, activating the renin–angiotensin–aldosterone system, to increase blood pressure.

no prostaglandins means no aldosterone

20
Q

addisons

A

adrenals can’t make mineralcorticoids

get lack of aldosterone and cortisol (which is actually a glucocorticoid)

21
Q

what do you think if someone’s potassium is 6.5-7 with no EKG changes

A

their sample may have been hemolysed, a lab error causing increased serum K in the plasma that isn’t actually in vivo

22
Q

having hyponatremia will do what if you have hyperkalemia

A

it will make it worse because you won’t be secreting K with the Na/K antiporter

23
Q

Tx for hyperkalemia and why

A

FIRST: antagonize
Calcium IV: antagonizes the effects of hyperkalemia on muscle cells in minutes

THEN: move into cells
glucose and insulin: shifts K into the cells

Bicarb: making them alkalemic shifts K into the cells via the K+/H+ antiporter

LATER…excrete
Loop diuretic
kayexalate
dialysis

24
Q

spironolactone does what to your potassium

A

hyperkalemia

spironolactone is an aldosterone receptor antagonist (THIS IS NOT THE SAME AS AN ARB. ARBS ARE ANGIOTENSIN RECEPTOR BLOCKERS like losartan)

so it blocks the Na/K antiporter

25
Q

values for hyper and hypo natremia

A

less than 135 or more than 145

26
Q

where is ADH made

A

produced in the hypothalmus supraoptic and paraventricular nuclei

get stored in secretary granules that move down to the posterior lobe of the pituitary

27
Q

Describe what is meant by non osmotic stimuli of ADH

A

Non osmotic sources of stimulation for ADH secretion

Come from baroreceptors for hypovolemia

can cause retention of water even if you have a low osmolality

used to keep the brain perfused and BP up in hypovolemia

28
Q

what does ADH bind to

A

V2 receptor

makes aquaporin 2 move into the luminal membrane

29
Q

does the kidney think the body is volume (overloaded or depleted) when on a diuretic

A

kidney can think that the body is volume depleted because you are getting rid of sodium on a diuretic

30
Q

urine osmolality of sodium can range from _____ -______

A

can dilute to 50 - can concentrate to about 1400

use 50-1000 for her calculations though for the test i guess……..

31
Q

when do you declare someone oliguric

A

when someome is making less that 500-600 cc of urine a day

32
Q

pseudohyponatremia

A

when you have a low sodium but your plasma osmolality is normal

states of high protein (like multiple myeloma) or high lipids (like high triglycerides) or high sugar ( like mannitol to treat cerebral swelling)

33
Q

high urine sodium means the kidneys are behaving as if the body is fluid _____ (expanded or depleted)

A

expanded

34
Q

how much water do you have to drink in order to overcome the renal capacity to excrete water

A

10-15 liters

35
Q

what are you thinking if someone is hyponatremic, urine osmolarity >100, UNa+ is less than 10

A

their body is trying to retain sodium so that they retain water. This is normal for hypovolemia

can be because of GI loss, burns, diuretics (late), cortisol deficiency

36
Q

what are you thinking if someone is hyponatremic, urine osmolarity >100, UNa+ is less than 10 but they are volume expanded

A

they probably have edema, but the kidney thinks that they are volume depleted due to hyponatremia, so the kidney is trying to retain sodium inappropriately (because it is not perfused)

may be due to CHF/cirrhosis/nephrosis

37
Q

what are you thinking if someone is hyponatremic, urine osmolarity >100, UNa+ >10, and volume depleted

A

this is a salt wasting nephropathy.

rarer, can be seen with diuretics (early), adrenal insufficiency, hypothyroidism

38
Q

what are you thinking if someone is hyponatremic, urine osmolarity less than 100

A

probably primary polydypsia, beer potomania, or tea and toast syndrome

they are getting rid of excess water to correct hyponatremia

THEY ARE NOT VOLUME DEPLETED SO THEY DON’T CONCENTRATE THEIR URINE

39
Q

what are you thinking if someone is hyponatremic, urine osmolarity >100, UNa+ >10, and volume appropriate or expanded

A

syndrome of inappropriate ADH secretion (SIADH) classically from lung cancer, also

40
Q

how do you treat someone who is hyponatremic and volume expanded

A

restrict free water intake or treat state of poor perfusion (diuretics)

41
Q

when would you give an ADH antagonist and what are they called

A

the “vaptans” target V2 receptors

hyponatremia with volume expansion

use them in an effort to get free water off

42
Q

what is the maximum rate of correction of hyponatremia

A

.5 meq/liter/hour

43
Q

what common-ish drug is known to cause nephrogenic diabetes insipidus?

A

lithium

need to give them just water, not saline

AAW - CRRAB 2 - week 4 (5 decks)

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