Potassium disorders

Question 1

Functions of Potassium

Answer 1

• Regulation of neuromuscular excitability and muscle contraction
• Regulation of insulin secretion (low K inhibits secretion; high K stimulates insulin secretion)

Question 1

Functions of Potassium

Answer 1

• Regulation of neuromuscular excitability and muscle contraction
• Regulation of insulin secretion (low K inhibits secretion; high K stimulates insulin secretion)

Question 2

Alkalosis and K levels

Answer 2

Alkalosis causes H to move out and K into the cell –> potential hypokalemia

Question 2

Alkalosis and K levels

Answer 2

Alkalosis causes H to move out and K into the cell –> potential hypokalemia

Question 3

Acidosis and K levels

Answer 3

Acidosis causes H to move into the cell and K out

Question 3

Acidosis and K levels

Answer 3

Acidosis causes H to move into the cell and K out

Question 4

Diarrhea and K levels

Answer 4

There is a loss of K and HCO3 in the stool –> hypokalemia and metabolic acidosis

Question 4

Diarrhea and K levels

Answer 4

There is a loss of K and HCO3 in the stool –> hypokalemia and metabolic acidosis

Question 5

Drugs that commonly cause low K

Answer 5

MCC: Loop and thiazide diuretics

Also, Insulin and beta-2 agonists may shift K into the cell

Question 5

Drugs that commonly cause low K

Answer 5

MCC: Loop and thiazide diuretics

Also, Insulin and beta-2 agonists may shift K into the cell

Question 6

Clinical findings in hypokalemia

Answer 6

• Muscle weakness (due to changes in membrane potential)
• U waves on ECG
• Collecting tubules become refractory to ADH –> nephrogenic DI –> polyuria
• Tubule cells become distended with fluid (vacuolar nephropathy)
• Rhabdomyolysis (low K inhibits insulin –> decreased muscle glycogenesis)

Question 6

Clinical findings in hypokalemia

Answer 6

• Muscle weakness (due to changes in membrane potential)
• U waves on ECG
• Collecting tubules become refractory to ADH –> nephrogenic DI –> polyuria
• Tubule cells become distended with fluid (vacuolar nephropathy)
• Rhabdomyolysis (low K inhibits insulin –> decreased muscle glycogenesis)

Question 7

MCC of hyperkalemia

Answer 7

Renal failure

Question 7

MCC of hyperkalemia

Answer 7

Renal failure

Question 8

Pseudohyperkalemia

Answer 8

RBC hemolysis from difficult venipuncture

Question 8

Pseudohyperkalemia

Answer 8

RBC hemolysis from difficult venipuncture

Question 9

Clinical findings of hyperkalemia

Answer 9

• Ventricular arrhythmias
• Peaked T waves on ECG (due to accelerated depolarization of cardiac muscle)
• Muscle weakness (high K interferes with membrane excitability by partially depolarizing it)

Question 9

Clinical findings of hyperkalemia

Answer 9

• Ventricular arrhythmias
• Peaked T waves on ECG (due to accelerated depolarization of cardiac muscle)
• Muscle weakness (high K interferes with membrane excitability by partially depolarizing it)

Question 10

Functions of Potassium

Answer 10

• Regulation of neuromuscular excitability and muscle contraction
• Regulation of insulin secretion (low K inhibits secretion; high K stimulates insulin secretion)

Question 11

Alkalosis and K levels

Answer 11

Alkalosis causes H to move out and K into the cell –> potential hypokalemia

Question 12

Acidosis and K levels

Answer 12

Acidosis causes H to move into the cell and K out

Question 13

Diarrhea and K levels

Answer 13

There is a loss of K and HCO3 in the stool –> hypokalemia and metabolic acidosis

Question 14

Drugs that commonly cause low K

Answer 14

MCC: Loop and thiazide diuretics

Also, Insulin and beta-2 agonists may shift K into the cell

Question 15

Clinical findings in hypokalemia

Answer 15

• Muscle weakness (due to changes in membrane potential)
• U waves on ECG
• Collecting tubules become refractory to ADH –> nephrogenic DI –> polyuria
• Tubule cells become distended with fluid (vacuolar nephropathy)
• Rhabdomyolysis (low K inhibits insulin –> decreased muscle glycogenesis)

Question 16

MCC of hyperkalemia

Answer 16

Renal failure

Question 17

Pseudohyperkalemia

Answer 17

RBC hemolysis from difficult venipuncture

Question 18

Clinical findings of hyperkalemia

Answer 18

- Ventricular arrhythmias - Peaked T waves on ECG (due to accelerated depolarization of cardiac muscle) - Muscle weakness (high K interferes with membrane excitability by partially depolarizing it)