Potassium Disorders Flashcards
What is the normal range of potassium in the serum?
4-5 mEq/L
Is there more potassium outside or inside the cells?
inside (98% intracellular)
What are the symptoms of potassium disorder?
cramps, weakness, paralysis, cardiac arrythmias
What changes would you see on EKG for hyperkalemia vs hypokalemia?
hyper: ST depression, T wave elevation! U wave
hypo: T wave depression
both: PR prolongation and QRS widening
How is Dig related to potassium levels?
hypokalemia increases Dig toxicity causing hyperkalemia
What are the main 4 factors that dictate potassium distribution and excretion?
1 concentration
2 acid base (acid out, basic in)
3 insulin/catecholamines (in)
4 Aldosterone (increase excretion)
What are some causes of hypokalemia?
1 increased entry into cells (met acidosis, increased insulin, beta agonist)
2 GI loss (vomiting, diarrhea)
3 urinary loss (diuretic, salt wasting)
How do you distinguish between a GI and renal cause of hypokalemia?
24 hr urinary K+:
UK+ decrease: GI
UK+ increase: renal
What are the main complications of hypokalemia?
cardiac arrhythmia, rhabdomyolysis, renal dysfn, HTN
When treating hypokalmia, what other electrolyte imbalance should you also check?
Mg+2 (low Mg+2 = increased excretion of K+)
Main causes of hyperkalemia are shift of K+ out of cells and decreased excretion. Name 2 examples of each.
1 shift out of cells (muscle breakdown, hyperlgycemia/DKA, metabolic acidosis)
2 decreased excretion (hypoaldosteronism, renal failure/NSAIDs/HIV/ACEi decrease renin, Aldosterone resistance-K+ sparing diuretics)
How do you differentiate pseudohyperkalemia from a “true” hyperkalemia clinically?
EKG changes along with increased K+ on electrolyte for true hyperkalemia
What are the 3 steps for treating hyperkalemia?
1 calcium - raise RMP/depolarize
2 shift K+ into cells- insulin/glucose, NaHCO3, beta agonist(ALbuterol)
3 remove K+- loop diuretics, Kayexalate, dialysis
