Potassium disorders (hypo and hyperkalemia)

what are the 3 main causes/classifications of disorders of potassium metabolism?

altered intake

altered elimination

deranged transcellular potassium shifts

What effect does insulin have on potassium? What can we use it to treat?

it causes K+ to go into the cell leading to hypokalemia (its based on the ECF)

can use it to lower K+ in hyperkalemia

hypokalemia and hyperkalemia are based on the levels of K in the _____

extracellular fluid

hyperkalemia is a lab result of ___

>5mmol/L

hyperkalemia due to potassium shifts: what are some causes?

rhabdo, hemolysis, burns, sepsis, met acidosis, insulin deficiency

explain exercise and potassium levels. What is the effect on the heart?

K+ is stored in the muscles so when you workout and break down muscle you get increased K+ in the ECF

the heart gets exposed to high levels of K during exercise and exposed to a major drop in K+ after exercise

hyperkalemia due to decreased excretion: what are somethings that can cause this?

sickle cell disease, hypoaldosteronism, ACEis, NSAIDs, and spironolactone

hyperkalemia due to increased dietary intake is uncommon and usually involves ____

concurrent renal insufficiency

the immediate danger of hyperkalemia is its effect on___ and ____

cardiac conduction and muscle strength

What are some of the at risk populations for hyperkalemia?

CKD, diabetes, heart failure, and liver disease

What are 4 things that we should do to approach a hyperkalemia case?

review the pts meds

ask about salt substitutes containing potassium

get a BP

assess for kidney hypoperfusion

What steps should you take as far as labs to address hyperkalemia?

repeat to check K+ level

additional labs: BUN/creatinine, glucose, urine electrolytes

EKG

What are some reasons when an EKG should be considered in a hyperkalemic pt?

K+ above 6

symptomatic

rapid onset

underlying kidney disease, heart disease, or cirrhosis

With hyperkalemia, what do we expect to see with EKG changes?

peaked T wave (earliest sign)

P-wave flattening

PR-interval prolongation

widening of QRS

can see arrhythmias 

What are the main 9 treatments for hyperkalemia?

• IV calcium

• insulin and glucose

• inhaled beta-agonist

• sodium bicarb

• hemodialysis (actually changes total body K+, not just a shift into cells)

• kayexalate

• patiromer (veltassa)

• sodium zirconium cyclosilicate (Lokelma)

• furosemide (loop diuretics)

What treatment for hyperkalemia binds K+ in exchange for sodium?

it lowers total body K+, but is associated with GI issues so is not used in pts with abnormal bowel function

kayexalate

What treatment for hyperkalemia is a powder solution that binds potassium int he lumen of the GI tract and increases fecal K+ excretion?

patiromer

pts should avoid ___ if they are hyperkalemic

NSAIDs

hypokalemia is when the K+ levels are ____

<3.4

What are some (5) etiologies for hypokalemia?

decreased intake, renal loss, potassium shift favoring intracellular, extrarenal loss, sample error

hyperaldosteronism, hypomagnesemia, RTA, etc. all can lead to ____

hypokalemia

insulin excess, alkalosis, beta-adrenergic excess, etc. can all lead to _____

hypokalemia

What is another electrolyte that is low when K+ is low?

magnesium

What do we expect to see on EKG if the pt is hypokalemic?

decreased T wave amplitude, ST-interval depression, U-waves, arrhythmias, T wave inversion

with urinalysis of hypokalemia, extrarenal cause we see ___ and renal cause we see ____

extrarenal: <30 mmol

renal: > 30 mmol

more K+ in urine if kidneys are fucked up

how do we treat hypokalemia?

ACE-I, ARB, beta-blocker, K+ sparing diuretic (spironolactone, eplerenone, triamterene, and amiloride), oral or IV potassium

What is important to remember with IV potassium?

do not give a bolus

give in normal saline (not dextrose solution)

when to recheck electrolytes with hypokalemia: 

emergency vs stable vs outpatient

emergency: every 1-2 hours

stable: 4-6 hours

outpatient: weekly until stable then monthly or quarterly