2.2 Cs Exam 1: Potassium Disorders

Front 1

what % of k+ is extracellular and what is the normal range of k+ of ECF k+?

Back 1

95% intracellular & 5% extracellular
normal range is 3.5-5.0 mEq/L

(*we measure extracellular NOT intracellular)

Front 2

what are the 4 different ways in which hypokalemia (potassium loss) can come about

What is the worst (most severe) cause of hypokalemia?

Back 2

shifting k+ intracellulary from ECF
extrarenal k+ loss (sweat, vomiting, diarrhea*)
renal k+ loss
decreased k+ intake

worst = diarrhea*

Front 3

what causes k+ to shift into the cells from ECF causing a dec in K+?

Back 3

insulin (best tx for hyperkalemia, give w glucose)
alkalosis (shifts from plasma into cells)

*(if an acidotic pt has low potassium, need to replace depleted potassium!!)

Front 4

what are some extrarenal k+ losses

what is the MC cause of hypokalemia d/t extrarenal K+ loss?

Back 4

diarrhea
gastric suctioning
chronic laxative use

infectious diarrhea = MC

Front 5

what is the most important regulator of the body k+ content?

An increased _______ will lead to hypokalemia & likely be accompanied by high BP

Back 5

aldosterone
(facilitates k+ excretion at the distal tubule)

increased aldosterone--> hypokalemia

Front 6

renal k+ loss can also be dt increased flow of distal nephron. what are some causes of this?

Back 6

diuretics - furosemide, thiazide
hypomagnesia** (leads to hypokalemia)
renal tubular acidosis

Front 7

what should you suspect if you have refractory hypokalemia despite k+ replacement?

Back 7

mg+ depletion

Front 8

What drugs can cause hypokalemia?

Back 8

Insulin (esp when treating diabetic ketoacidosis)

B2-adrenergic agonists

Diuretics (loop--> cause Renal K & Mg loss)

(*hypokalemia also inc risk of digitalis toxicity)

Front 9

what accounts for most of the sx that accompany hypokalemia

Back 9

altering the membrane resting potential

Front 10

why do athletes eat bananas before working out

Back 10

prevents mild to moderate hypokalemia sx:

muscular weakness
fatigue
muscle cramps
constipations <-- this is why your mom tells you to eat a banana when you can't poop

Front 11

what are some severe hypokalemia (< 2.5 mEq/L) sx

Back 11

flaccid paralysis
hyporeflexia
rhabdomyolysis
tetany

hypercapnia

Front 12

what would the ekg for a hypokalemic pt look like

Back 12

broad T waves
decreased amplitude
prominent U waves

low pot = no T(ea), just U

Front 13

is acute or subacute and chronic hypokalemia more dangerous?

Back 13

subacute and chronic are the MC and usully not life threatening

acute hypokalemia is less common and usu life threatening* (most dangerous)

Front 14

what is the safest way to tx mild to moderate deficiency hypokalemia

Back 14

oral k+

(tx of choice unless ECG changes OR severes!)

Front 15

how is severe hypokalemia treated? what are some stipulations that come with treatment

Back 15

must be treated via IV K & correct Mg def*

must have continuous cardiac monitoring while administering IV k+

recheck q 4-6 hours

Front 16

NEVER give k+ at a transfusion rate > ________

Back 16

40 mEq/L per hour

*typically is ia 10 mEq/hr over 4-6 hours & given w/ lidocaine bc painful

Front 17

what organ system can be most dangerously affected by hyperkalemia (> 5.5 mEq/L)?

What symptoms would it cause?

Back 17

cardiac (also affects neuromuscular)

hypotension, dysrhythmias, ECG changes

muscle weakness, lethargy, paralysis, areflexia

Front 18

what would hyperkalemia look like on EKG

Back 18

tall peaked T waves
absent p waves
wide QRS
prolonged QT

**note you must obtain an EKG immediately if the pt has HYPERkalemia

Front 19

what are the drugs that can cause hyperkalemia

Back 19

K + sparing duretics

Captopril

(Triamterone, spironolactone)

Beta-blockers

digoxin

succinylcholine

Front 20

what is one of the first questions you should ask a hyperkalemic patient

Back 20

do they have renal failure?

Front 21

what are the causes of hyperkalemia

Back 21

renal failure*

aldosterone insufficiency (low)

Cellular breakdown (tumor-lysis, rhabdomyolysis)

hemolysis

GI Bleed

Salt substitutes containing K+

Ketoacidosis

Front 22

What can cause a false hyperkalemia ?

Back 22

thrombocytosis

leukocytosis

prolonged tourniquet time

in-vitro hemolysis

(trauma to RBC--> inc intracellular K+)

Front 23

what is the tx of hyperkalemia if serum k+ <6.5 and there are NO ekg signs

Back 23

increase k+ excretion through bowels or kidneys or decrease k+ intake

ex) kayexalate

Front 24

what are some treatments for emergent hyperkalemia

Back 24

Calcium gluconate (& Na bicarb- FASTEST, but shortest)

glucose, insulin
albuerterol (b agonist)
diuretics or peritoneal or hemodialysis (slower)

Bicarbonate therapy (used if metabolic acidosis*)

Front 25

after emergent treatment, what should you put the patient on

Back 25

longer acting therapy with dialysis
or exchange resin (kayexalate)