HyperKalemia and Hypo Flashcards
Normal serum K is?
3.5-5.0 m Eq/L
Increased intake of what 2 things can cause hyperkalemia?
PO supplementation, IV potassium.
Pseudohyperkalemia from mechanical trauma when what happens?
Can have mechanical trauma from venipuncture. - Can see red serum (giveaway)
This could also be true severe intravascular hemolysis though.
Exercise- repeated clenching of the first during venipuncture, cooling of sample or deterioartion of sample, thrombocytosis, and severe leukocytosis can all lead to?
Hyperkalemia
What 3 things cause decreased excretion of potassium?
Renal failure(acute or chronic), hypoaldosteronism, hypovolemia.
Any breakdown of cells, acidosis, and insulin deficiency/resistance can lead to?
Hyperkalemia
Broken cells release potassium when they lyse
H+ moves from the blood into the cell in exchange for K+
Insulin causes K+ entry into cells.
What ion is exchanged for K+ when moved into the cell
H+. Therefore could be hyperkalemic in acidosis
Insulin effects K+ how?
Insulin causes K+ entry into cells
With deficiency can cause hyperkalemia
ACEi’s ARBs, Bactrim, Beta blockers can all cause?
Hyperkalemia
How does potassium cause cardiotoxicity?
Hyperkalemia causes cardiotoxicity by increasing the resting membrane potential of the cardiac myocyte, causing “membrane excitability”
At very high levels, potassium causes the depolarization threshold to rise, leading to overall depressed cardiac function
S/S of hyperkalemia?
Vague and varied symptoms, but usually asymptomatic
May have: N/V, palpitations, lethargy, confusion, paresthesias, muscle weakness, paralysis if advanced, arrythmias/death.
How should you work up a patient with hyperkalemia?
Repeat potassium level if there’s any doubt about veracity
Serum potassium will be above 5.0
BMP to assess renal function, look at BUN:Cr
EKG
Consider ABG if suspecting acidosis.
Describe the sequential order of EKG changes in hyperkalemia.
- 5-6.5
- 5-7.5
- 0-8.0
>8.0
Peaked T wave - K5.5-6.5 mEq/L
Flattened P wave with prolonged PR interval or totally absent P wave. 6.5-7.5
Wide QRS 7.0-8.0
Sine wave pattern portending imminent cardiac arrest. K>8.0
Hyperkalemia is considered an emegency when it is above what level? What are other signs that make it an emergency?
Potassium is greater than 6.5
There are clinical s/s of hyperkalemia like muscle weakness, paralysis, arrythmias.
Or above 5.5 and significant renal impairment.
What is the treatment for severe hyperkalemia and EKG changes?
IV calcium gluconate. - stabilizes the heart.
Insulin + glucose can be used to treat what?
Hyperkalemia, to help drive potassium back into the cell
Albuterol can be used to treat what electrolyte imbalance?
Hyperkalemia
What are 3 ways you can remove potassium from the body?
GI cation exchanger
Diuretics
Hemodialysis
How do GI cation exchanger’s work to treat hyperkalemia?
Bind K+ in the GI tract in exchange for other cations –> excreted in the feces
Kayexalate - sodium polystyrene sulfonate
Patiromer (veltassa)
What Diuretic can be used to treat hyperkalemia?
Lasix or other loop diuretic.
Common s/e is hypokalemia
Diuretics, Hyperaldosteronism, vomiting, diarrhea, insulin excess, beta agonist treatment, alkalosis, hypomagnesmia, renal tubular acidosis, low calorie diets, can all cause?
Hypokalemia
What are ways Potassium is lost in the body?
Renal and GI
Renal - diuretics or hyperaldosteronism
GI - vomiting and diarrhea.
Movement of potassium from blood into intracellular compartment occurs in what 3 scenarios?
Insulin excess - insulin helps drive K+ into the cell
Beta agonist treatments - similar to insulin
Alkalosis. H+ is exchanged for K+ for cell entry.
If you keep trying to get K+ up and its not working what other elctrolyte should you check?
Magnesium. - Concurrent Mg & K+ losses in diuretics and vomitting.
Diuretics, amphotericin B, antipsychotics (risperdal and seroquel), Barium or chloroquine intoxication can cause what?
Hypokalemia.
S/s of hypokalemia?
No pathognnomonic presenting s/s
May have muscle fatigue or weakness- often starts in the LE, progresses to the turnk UE, can end in paralaysis
Cramps, rhabdomyolysiss, myoglobinuria
Respiratory muscle weakness –> respiratory failure/death
GI muscle involvement: ileus, constipation, n.v
What 3 diagnostic tests should you run when someone has hypokalemia?
BMP
Magnesium
EKG
What are the EKG findings of hypokalemia?
Flattened or inverted T waves
More prominent U waves
ST depression
Prolonged QT interval “QU interval”
Arrythmias - V tac, V fib, torsades.
If a patient is having cardiac symptoms or their potassium is below 2.5, what should be their treatment?
IV potassium - can cause phlebitis and pain though.
If a patient is not having cardiac manifestations or their potassium is above 2.5 then what should be their treatment?
Oral potassium.
If a patient has low potassium and low magnesium can you just fix the potassium?
No - magnesium needs to be repleted as well.
