Potassium Handling

Question 1

What is the effect of Digoxin on potassium movement?

Answer 1

Digoxin competes with potassium and inhibits movement into the cell. Insulin deficiency, beta-2 antagonists, and alpha-1 agonists also decrease entry of potassium into the cell.

Question 2

Where will potassium move (relative to the cell) in a metabolic acidemia?

Answer 2

In a metabolic acidosis potassium will leave the cell. This is due to an interchange of positive and negative electrolytes (H+ and Cl-) which results in there being more negative charge outside the cell and therefore potassium moves outside the cell.

Question 3

Where will potassium move with administration of insulin?

Answer 3

Potassium will move into the cell with insulin as insulin up regulates the Na+/H+ ATPase.

Question 4

Where does potassium move in relation to aldosterone secretion?

Answer 4

Potassium is wasted (moves out of the cell) with aldosterone.

Question 5

What is the treatment for hyperkalemia?

Answer 5

IV calcium
Insulin + glucose
Diuresis: NaHCO3 + Furosemide

C BIG K Drop 
C = IV Calcium
BIG = Beta agonist, insulin, glucose
K = Kayexalate
DROP = Diuretics, Dialysis

Question 6

What should the TTKG be in a patient with increased potassium?

Answer 6

The TTKG should be high. In hyperkalemia, if the TTKG is less than 7 this is inappropriate and you have a principle cell problem.

Question 7

What should the TTKG be in a patient with decreased potassium?

Answer 7

The TTKG should be low. In hypokalemia, if the TTKG is >4 this is abnormal, and you can blame the principal cell.

Question 8

Where does potassium move in relation to the cell in a metabolic alkalemia?

Answer 8

A metabolic alkalemia will drive potassium into the cell.

Question 9

Where does potassium move in relation to the cell with beta-2 stimulation?

Answer 9

With beta-2 stimulation potassium will move into the cell.

Question 10

What are the ECG changes in hyperkalemia?

Answer 10

ECG in Hyperkalemia:

• increase in T wave amplitude with peaking
• prolongation of the PR interval
• flattening or absence of the p wave
• prolongation of QRS and ventricular arrhythmias
• QRST sine wave

Question 11

What are the ECG changes in hypokalemia?

Answer 11

ECG in Hypokalemia:

• T wave flattening and QT prolongation
• U waves
• ST segment depression and T wave inversion