Disorders of Potassium Metabolism

Question 1

What is the relationship between plasma potassium and blood pH?

Answer 1

Plasma [K+] rises with acidemia and falls with alkalemia

Question 2

What is the relationship between insulin and plasma potassium?

Answer 2

A rise in K+ triggers an insulin release EVEN WITHOUT GLUCOSE. This leads to a movement of potassium into cells.

Question 3

What is the relationship between beta agonists and K+?

Answer 3

Beta two agonists stimulate entry of K+ into cells

Question 4

Do highly trained athletes have hypokalemia or hyperkalemia?

Answer 4

Highly trained athletes shift potassium into their cells, while leaving total body potassium unchanged, leading to hypokalemia.

Question 5

What drug causes hyperkalemia by inhibiting the Na/K ATP-ase?

Answer 5

Digoxin

Question 6

What are the four major determinants of urinary potassium excretion?

Answer 6

1. Normal distal tubule function.
2. Aldosterone activity
3. Urine flow rate
4. Delivery of non-reabsorbed anions to the distal nephron

Question 7

Is potassium adaptation a fast or slow thing to turn off?

Answer 7

Slow.

It’s also worth noting that potassium adaptation is a thing.

Question 8

What are the metabolic effects of hypokalemia?

Answer 8

Hypokalemia suppresses insulin release leading to glucose intolerance. It also retards growth in children

Question 9

What are the cardiovascular effects of hypokalemia?

Answer 9

Causes the appearance of U waves after repolarization. Enhances development of atrial and ventricular arrhythmias in patients on digitalis.

Question 10

What are the neuromuscular effects of hypokalemia?

Answer 10

Hypokalemia causes muscle weakness or even paralysis

Question 11

What are the renal effects of hypokalemia?

Answer 11

It causes an increased thirst and a renal concentrating defect resulting in polyuria.

Question 12

What is the cause of hypokalemia with potassium deficit that has a star next to it on the handout?

Answer 12

GI loss from protracted vomiting or diarrhea

Question 13

Which is MORE common, hypokalemia or hyperkalemia?

Answer 13

HypOkalemia

Question 14

Which is MORE dangerous, hypokalemia or hyperkalemia?

Answer 14

HypERkalemia

Question 15

What are the cardiac effects of hyperkalemia?

Answer 15

Raises cell membrane potential towards the threshold, then an unpredictable progression through bad ECG findings to a SINE WAVE.

Question 16

I say SINE WAVE and you say ____

Answer 16

Hyperkalemia

Question 17

What is pseudohyperkalemia?

Answer 17

A rise in potassium following destruction of cells, commonly after a blood draw.

Question 18

What are the 3 categories of causes of hyperkalemia?

Answer 18

1. A shift from ICF to ECF
2. Decreased excretion
3. Increased input