Hyperkalemia and Hypokalemia Flashcards
Hyperkalemia is serum potassium > ____
5.0mEq/L
Where is most total body calcium stored?
Intracellular
3 broad causes of hyperkalemia
Decreased K+ excretion
Increased K+ intake
Intracellular to extracellular shifts of K+
Falsely high K+ is called ______. Name some causes of it?
pseudohyperkalemia: Mechanical trauma from venipuncture cooling or deterioration of sample thrombocytosis severe leukocytosis
Causes of decreased excretion of K+?
Renal failure
hypovolemia
hypoaldosteronism
Causes of intracellular to extracellular shift of K+?
Any breakdown/lysis of cells
Acidosis
Insulin deficiency or resistance
A lot of meds can cause hyperkalemia. Name some of them.
ACEIs**** ARBs**** K+ sparing diuretics ****(spironolactone) Bactrim**** Beta blockers Digitalis succinylcholine amiloride K+ supplements
What affect of does hyperkalemia have on the heart?
Increases the resting membrane potential of the cardiac myocyte causing membrane excitability.
Symptoms of hyperkalemia?
Usually asymptomatic, can have vague and varied symptoms.
What diagnostics might you order in a patient with hyperkalemia?
BMP to assess renal function
EKG
ABG if suspecting acidosis
What EKG changes are seen in hyperkalemia?
What serum potassium do they correspond to?
Peaked T waves - 5.5-6.5
Flattened P waves with prolonged PR interval or absent P waves 6.5-7.5
Wide QRS 7-8
Sine wave pattern - >8.0
Which of the following EKG changes makes you shit you pants the most?
a) Prominent U wave
b) Diffuse ST segment elevation
c) Peaked T waves
d) Sine wave pattern
d) sine wave pattern
What level of hyperkalemia is considered an emergency in an otherwise healthy patient?
> 6.5
A serum potassium of >5.5 is considered an ermegency if the patient has ?
Significant renal impairment
Ongoing tissue breakdown
Ongoing K+ absorption
Significant acidosis
What is the first pharmacologic therapy you would use in a hyperkalemic patient with EKG changes?
IV calcium gluconate
Oh shit, your tech just spilled the last dose of IV calcium gluconate. What pharmacologic therapies will drive potassium back into the cell to buy you some time until you can get more calcium gluconate from the nearest hospital?
Insulin+glucose
Beta-2 adrenergic agonists (albuterol)
IV sodium bicarbonate.
What does calcium gluconate do?
Stabilizes the cardiac cell membranes
What pharmacologic therapies serve to remove potassium from the body?
GI cation exchangers (kayexalate, patiromer) Loop diuretics (lasix)
hypokalemia is serum potassium below ____
3.5
What are 2 broad categories of things that cause hypokalemia?
Increased loss
Movement of K from blood to intracellular compartment
What are some causes of increased loss of K?
Renal tubular acidosisWhat
Loop diuretics, hyperaldosteronism
Vomiting/diarrhea
What are some causes of movement of K+ from blood to intracellular compartment?
Insulin excess
Beta agonist treatment
Alkalosis
When you find out your patient is hypokalemic, what lab do you need to check next?
Why?
Serum magnesium
Need to fix magnesium in order to fix potassium
EKG findings in hypokalemia?
Flattened or inverted T waves More prominent U waves in leads v4-v6 ST depression QU interval Arrhythmia
Treatment for hypokalemia?
Potassium replacement (either IV or PO)
Side effects of administering IV potassium?
Pain and phlebitis
