Class: Potassium disorder

Question 1

What is the major route by which potassium is eliminated from the body

Answer 1

Urine

Question 2

What 3 things regulate K+ balance

Answer 2

Na/K ATPase
catecholamines
insulin

Question 3

What happens to most filtered K+

Answer 3

Most of the filtered K is reabsorbed in the proximal tubule and loop of Henle

Question 4

What do CD intercalated cells do with K+?

CD principal cells?

Answer 4

intercalated - reabsorb

principal cells - excrete

Question 5

define normal, hyperkalemic, and severe hyperkalemic levels

Answer 5

normal = 3.5-5
hyper = > 5.5
severe = >6.5

Question 6

What causes Pseudohypekalemia- (3) and a reason

Answer 6

hemolysis, leukocytosis, thrombocytosis (k released from these cells- serum value not plasma)

Question 7

What is #1 reason fro hyperkalemia

Answer 7

renal failure

Question 8

4 reasons for hyperkalemia (besides renal failure)

Answer 8

Metabolic acidosis
Hyperglycemia
tissue breakdown - most K+ is inside muscle cells
Hypoaldosteronism

Question 9

Symptoms of hyperkalemia usually start at what level

Answer 9

> 6.5

Question 10

2 Symptoms of hyperkalemia

Answer 10

Muscle weakness, paresthesias

Arrythmia

Question 11

How does hyperkalemia cause arrythmia

Answer 11

High K concentration–> inactivation of sodium channels–> decreased excitability

Question 12

EKG hyperkalemia sign

Answer 12

peaked T wave

Question 13

What is resting mb potential with hyperkalemia

Answer 13

more positive (closer to threshold)

Question 14

What does giving Calcium gluconate due to decrease arrythmias dt hyperkalemia

Answer 14

it raises threshold potential

Question 15

hypokalemia and severe hypokalemia defined as

Answer 15

hypo = < 3.5
severe = < 2.5

Question 16

Causes of Hypokalemia (5)

Answer 16

Alkalosis
periodic paralysis
hypothermia- causes shift into cells
pseudohypokalemia- metabolically active cells take up K+ after blood drawn
Hypomagnesemia

Question 17

how does alkalosis cause hypokalemia

Answer 17

h ions released and move to the extracellular fluid to minimize the elevation in pH. To preserve electroneutrality, extracellular k enter the cells

Question 18

Bartter Syndrome: MOA, result, inheritance pattern

Answer 18

AR, mimics loop diuretics to cuase hypokalemia and metabolic alkalosis

Question 19

How does bartter syndrome present (3)

Answer 19

Presents early in life with
low BP
mental and growth retardation

Question 20

Gittelman’s syndrome:

presents when, mimics what, result

Answer 20

presents later in life
mimics thiazides (Genetic defect of Na-Cl cotransporter in distal tubule)
result is hypokalemia and metabolic alkalosis

Question 21

primary defect and urine pH in RTA type 1

Answer 21

impaired distal acidification, pH > 5.5

Question 22

primary defect in RTA type 2

Answer 22

impaired proximal bicarbonate reabsorption, pH <5.5

Question 23

primary defect in RTA type 4

Answer 23

decreased aldosterone secretion, pH <5.5

Question 24

2 hypokalemia sx

Answer 24

Muscle Weakness and cardiac arrhythmia

Question 25

MOA of arryhtmia in hypoK

Answer 25

less extracellular K –> less inward current –> slower repolarization

Question 26

EKG sign of hypokalmia

Answer 26

U waves

Question 27

If hypokalemia is accompanied by acidosis which do you correct first

Answer 27

start to correct hypokalemia before correction of acidosis