Potassium Disorders

Question 1

What common caused of Pseudohyperkalemia (Falsely elevated)?

Answer 1

Hemolysis
Repeated fist clenching with tourniquet in place
Thrombocytosis or Leukocytosis

Question 2

How do you manage Pseudohyperkalemia?

Answer 2

Repeat the sample

Question 3

What are common causes of Decreased Excretion of Potassium?

Answer 3

Renal Failure

Aldosterone Decrease

Question 4

What are common causes of Aldosterone Decrease?

Answer 4

ACE-I/ARBs
Type IV RTA (hyporeninemic, Hypoaldosteronism)
Spironolactone and Eplerenone (Aldosterone inhibitors)
Triamterene and Amiloride (K sparring diuretics)
Addison Disease

Question 5

What are common causes of Increased Potassium release from Tissues?

Answer 5

Tissue destruction: hemolysis, rhabdo, Tumor Lysis syndrome

Decreased Insulin

Acidosis

Beta blockers and digoxin

Heparin

Question 6

How does Decreased Insulin lead to Hyperkalemia?

Answer 6

Insulin normally drives K into cells

Question 7

How does Acidosis lead to Hyperkalemia?

Answer 7

Cells pick up Hydrogen ions (Acid) and release Potassium into serum

Question 8

How do Beta-blockers and Digoxin lead to Hyperkalemia?

Answer 8

Inhibition of the Na/K ATPase that normally brings K into cells

Question 9

How does Heparin Increase Potassium levels?

Answer 9

Increased tissue release

Question 10

What do potassium disorders interfere with?

Answer 10

Muscle contraction and cardiac conductance

Question 11

What are common symptoms of Hyperkalemia?

Answer 11

Weakness
Paralysis
Ileus: paralyzed gut muscles
Cardiac Rhythm disorders

Question 12

What is the most urgent test in sever Hyperkalemia?

Answer 12

EKG

Question 13

What EKG changes are seen with Severe Hyperkalemia?

Answer 13

Peake T waves
Wide QRS
PR prolongation

Question 14

How do you treat Hyperkalemia?

Answer 14

Lower Potassium by moving it into cells or removing from the body

Question 15

In life-threatening Hyperkalemia (abnormal EKG) what do you give?

Answer 15

calcium Chloride or Ca Gluconate to stabilize the myocardium

Insulin and glucose to drive K into cells

Bicarbonate: to drive K into cells

Question 16

What is the mechanism of Sodium Polystyrene Sulfonate (Kayexalate)?

Answer 16

removes K from the body through the bowel: binds K in the gut and removes it from the body

Question 17

What are Patiromer and Zirconium used for?

Answer 17

Long-term PO K-lowering agents that can be used chronically

Question 18

What are common Mechanisms of Hypokalemia?

Answer 18

Decreased Intake

Shift into cells

Renal Loss

GI loss

Question 19

What are common causes of K shifting into cells leading to Hypokalemia?

Answer 19

Alkalosis

Increased Insulin

Beta adrenergic stimulation

Question 20

How does Alkalosis lead to Hypokalemia?

Answer 20

Hydrogen ions are released from cells in exchange for K

Question 21

How does Beta Adrenergic stimulation lead to Hypokalemia?

Answer 21

accelerates the Na/K ATPase pump

Question 22

What are common causes of Renal Potassium loss?

Answer 22

Loop Diuretics

Increased Aldosterone

hypomagnesemia

RTA

Question 23

What are common causes of increased Aldosterone leading to Hypokalemia?

Answer 23

Primary Hyperaldosteronism (conn’s syndrome)
Volume depletion: increases aldosterone
Cushing syndrome
Bartter Syndrome: Na loss in loop of Henle
Licorice

Question 24

How does Hypomagnesemia lead to Hypokalemia?

Answer 24

Mg-dependent K channels open and spill K into urine when Mg is low

Question 25

What type of RTA cause Hypokalemia?

Answer 25

Proximal and Distal

Question 26

How does Hypokalemia commonly present?

Answer 26

Weakness, Paralysis and Loss of Reflexes

Question 27

What is the most characteristic EKG finding of Hypokalemia?

Answer 27

U waves

Question 28

What are other possible EKG findings associated with Hypokalemia?

Answer 28

Ventricular Ectopy (PVC), Flattened T-waves, ST depression

Question 29

How do you treat Hypokalemia?

Answer 29

Restore K level and manage the cause of Hypokalemia -PO replacement: no maximum rate -IV replacement: slowly to avoid fatal arrhythmia

Question 30

What are 3 Genetic disorders that lead to Hypokalemia?

Answer 30

Bartter Syndrome Gitelman Syndrome Liddle Syndrome

Question 31

What Drug analogy is used for Bartter Syndrome?

Answer 31

Furosemide at the loop of Henle causing a loss of Na absorption

Question 32

What lab changes are seen in Bartter Syndrome?

Answer 32

Low Blood pressure, High Urine Chloride and Low Serum Potassium

Question 33

What drug analogy is used for Gitelman Syndrome?

Answer 33

Thiazide at the distal tubule causing a loss of Na absorption

Question 34

What lab changes are seen in Gitelman Syndrome?

Answer 34

Low Blood Pressure, High Urine Chloride and Low serum Potassium

Question 35

What drug analogy is used for Liddle Syndrome?

Answer 35

Excess aldosterone at the Distal Tubule causing Excess ENaC channel activity

Question 36

What lab changes are seen in Liddle Syndrome?

Answer 36

High Blood Pressure, Low Urine Chloride and Low Serum Potassium