Paulson - Potassium Flashcards
hyperkalemia definition
K+ > 5.0
hyperkalemia refers to high __ K+
serum
what organ regulates K+ levels
kidney
nl K+
3.5-5.0
4 causes of hyperkalemia
increased intake
decreased excretion
shift from intracellular to extracellular
pseudohyperkalemia
increased intake of K+ (2)
supplements
IV
mc cause of pseudohyperkalemia
mechanical trauma → venipuncture → hemolysis and K+ leakage from cell
what do you think when you see pseudohyperkalemia
hemolysis
causes of decreased excretion of K+ (3)
arf/ckd
hypovolemia/volume depletion
hypoaldosteronism (adrenal insufficiency)
4 causes of hypovolemia
dehydration
chf
cirrhosis
low flow to kidneys
what causes intracellular to extracellular shifts (3)
any breakdown of cells
acidosis
insulin deficiency of resistance
causes of cell breakdown (4)
trauma
rhabdo
tumor lysis syndrome
pseudohyperkalemia
how does insulin affect K+
K+ follows insulin into cells → deficiency causes accumulation in serum → hyperkalemia
meds that cause hyperkalemia
ACEIs
ARBs
NSAIDs
spironolactone
beta blockers
digitalis
succinylcholine
bactrim
K+ supplements
how does hyperkalemia affect the heart
membrane excitability → depressed fxn → cardiotoxicity
mc presentation of hyperkalemia
asymptomatic
possible sx of hyperkalemia
n/v
palpitations
lethargy
confusion
paresthesias
muscle weakness
paralysis
arrhythmias
death
labs for hyperkalemia dx
check and recheck K+
BMP
EKG
+/- ABG
classic/mc EKG finding for hyperkalemia
peaked T waves
what level are peaked T waves seen in hyperkalemia
5.5-6.5 → early finding
other EKG findings of hyperkalemia (early → late) (3)
flattened p wave w. prolonged PR interval or absent P wave
wide QRS
sine wave pattern
latest ekg finding of hyperkalemia
sine wave pattern
what level is sine wave pattern seen in hyperkalemia
K+ > 8.0
emergent signs of hyperkalemia
clinical sx → esp muscle weakness or paralysis, arrhythmias
K+ > 6.5
K+ > 5.5 PLUS significant renal impairment PLUS ongoing tissue breakdown OR ongoing K+ absorption OR acidosis
tx for hyperkalemia (5)
IV calcium glconate
continous cardiac monitoring
drive K+ back into cell
remove K+ from the body
stop K+ supplements/drugs
when is calcium gloconate used for hyperkalemia
severe (>6.5)
PLUS
EKG changes
options to drive K+ back into cell
insulin PLUS glucose
SABA → albuterol
IV sodium bicarb
how do you remove K+ from the body (3)
GI cation exchanger
diuretics → Lasix + saline
hemodialysis
how do GI cation exchangers work
bind K+ in GI tract in exchange for other cations → excreted in feces
examples of GI cation exchangers
sodium polystyerene solfonate (Kayexalate)
patiromer (Veltassa)
when is hd indicated for hyperkalemia
severe renal impairment
hypokalemia definition
K+ < 3.5
causes of hypokalemia (6)
increased loss
movement of K+ from blood → intracellular
hypomagnesemia
renal tubular acidosis
meds
very low kcal diets
K+ losses often concurrent w. __ losses
Mg → diuretics vomiting
what meds cause hypokalemia
diuretics (minus K+ sparing - spironolactone)
amphotericin B
antipsychotics
barium/chloroqine intoxication
what common antipsychotics cause hypokalemia
risperdal
seroquel
sx of hypokalemia
muscle fatigue/weakness
cramps, rhabdo, myoglobinuria
resp muscle weakness/failure
ileus, constipation, n/v
where does K+ muscle fatigue/weakness start
LE → ascending
dx for hypokalemia
bmp
Mg → separate test
EKG
ekg findings for hypokalemia
flattened/inverted T wave
U wave in V4-V6
ST depression
prolonged qt → qu interval
arrhythmia
ex ekg of K+ 1.7
emergent indications for hypokalemia
cardiac manifestations
K+ < 2.5
tx for emergent hypokalemia
IV K+
s.e of IV K+ (2)
pain
phlebitis
tx for non emergent hypoklaemia
oral KCl
tx for hypokalemia + hypomagnesemia
replete both
