OnlineMedEd: Nephrology - "Potassium"

Question 1

Review the etiologies of hyperkalemia.

Answer 1

• Iatrogenic: ACE inhibitors, ARBs, aldosterone antagonists
• CKD and ingestion of high-K foods like citrus or bananas
• Artificial: hemolysis or squeezing your hand during a blood draw can cause this

Question 2

Why should you recheck a potassium?

Answer 2

In an asymptomatic person who has no reason to have potassium abnormalities, there’s a chance that the abnormal lab was artificial. Rechecking could reveal a normal underlying lab.

Question 3

Hyperkalemia causes what ECG abnormalities?

Answer 3

Peaked T waves and widened QRS complexes

Question 4

When you see an abnormal potassium, the first thing you need to do is ______________.

Answer 4

check an ECG; if you see ECG changes, then you need to give IV calcium right away

Question 5

Dustyn’s system for dealing with hyperkalemia is “stabilize, temporize, and decrease total body potassium.” Go through what this means.

Answer 5

• Stabilize: if the person has ECG changes, then give CaCl IV to immediately stabilize them. This lasts only minutes.
• Temporize: give beta-agonists, insulin with D50, and bicarb. These agents shift potassium into cells.
• Decrease total body potassium: kayexalate and loop diuretics can increase GI and urinary losses of potassium; dialysis can be used if the person has renal failure

Question 6

Review the etiologies of hypokalemia.

Answer 6

• Iatrogenic: thiazides, loop diuretics
• GI losses: diarrhea, vomiting
• Renal losses: Barter’s, Gittelman, Conn syndrome, hyperaldosteronism

Question 7

If you give lots of potassium (to replete hypokalemia) and it still doesn’t rise, then check for low ______________.

Answer 7

magnesium

Low magnesium can cause low potassium (not sure how).

Question 8

In general, giving _________ potassium raises the serum potassium by _______.

Answer 8

10 mEq; 0.1 mE