K+ diseases

Question 1

normal urine K+

Answer 1

45-112 mEq

Question 2

K+ moves out of ICF to ECF

Answer 2

in presence of acidemia and hyperosmolarity

Question 3

Factors affect Internal K+ balance

Answer 3

Plasma K+ highest –> lowest
non-anion gap metabolic acidosis
anion gap metab acidosis
alkalemia

Question 4

effect of alkalosis on K+ secretion

Answer 4

1) incr K+ entry into cells from ECF
2) incr apical membrane K+ permeability due to less H+ blocking K+ channels

–> hypokalemia

Question 5

Effect of aldosterone in cells

Answer 5

1) activ of apical Na channels (incr Na channel synthesis)
2) incr expression of basolateral Na/K
3) equal affinitiy betwen aldosterone and glucocorticods (cortisol)

Question 6

Normal distal tubule function

Answer 6

1) normal tubular epith function

2) aldosterone
3) urine or tubular flow rate

4) urinary excretion of anions = drags along K+ charge

Question 7

in absence of aldosterone, effect on total body K+ and plasma K+

with high plasma K+ effect on aldosterone

Answer 7

incr both

incr aldosterone for K+ secretion

Question 8

GI potassium excretion vs. skin K+ excretion

Answer 8

GI = diarrhea incr fecal K+ loss (laxative esp)

Skin = with large sweat, high K+ loss, sweat under control fo aldsterone

Question 9

K+ adaptation compared to sodium adaptation in timing

Answer 9

K+ adaptation is slow to turn on or off

Question 10

in chronic renal failure with same dietary K+ intake, effect on kidney

Answer 10

each nephron has to incr K+ excretion to maintain external K+ balance

hyperkalemia problem in acute renal failure and severely low

Question 11

Approach to hypokalemia

Answer 11

1) is there transcellular shift?
- alkalemia, excess insulin, excess beta agonist (isoproteronol), thyrotoxicosis

2) is there low K+ intake
3) is there GI loss of K+ (diarrhea, vomiting)
4) is there XS renal loss (diuretics)

Question 12

treatment of hypokalmeia

Answer 12

1) acute = cardiac arrhythmia or paralysis = IV K+

2) K+ sparing diuretics (spiro, triamterene, amiloride)

Question 13

metabolic effects of hypokalemia

Answer 13

1) decr insulin, high glucose
2) poor growth
3) intracellular acidosis
4) decr renal NH3= cirrhosis or encpahlopahty

Question 14

cardiovascular effect of hypokalemia

Answer 14

U waves and flattened T waves

Question 15

neuromuscular effect of hypokalemia

Answer 15

muscle weakness, paralysis, rhabomyolysis

Question 16

renal effect of hypokalemia

Answer 16

1) incr thirst
2) polyuria
3) proteinuria
4) decr GFR

Question 17

cardiac effect of hyperkalemia

Answer 17

1) peaked T waves
2) prolonged QRS and PR interval
3) ventricular fibrillation, cardiac arrest

EKG CHANGE WITH HYPERKALEMIA = EMERGENCY

Question 18

Neuromuscular effect of hyperkalemia

Answer 18

due to depolarization
weakness
paralysis

Question 19

Approach to hyperkalemia

Answer 19

1) if K+ > 6.0 an EKG should be performed immediately

2) is there transcellular shift
- acidemia, massive digitalis, adrenergic block, hyperosmolar state

3) is there decr renal K+ excretion
- GFR 40
- dietary intake > 300
KCL or XS dietary K+ intake

Question 20

treatment of hyperkalemia

reversible depolarization

Answer 20

calcium infusion

Question 21

treatment of hyperkalemia

shift K+ into cells

Answer 21

insulin
beta agonist
bicarb infusion

Question 22

remove K+ from body

Answer 22

Kayexelate
diuretics
hemodialysis

Question 23

45 y/o woman with 3 day history of n/v/anorexia
stopped insulin
on beta blocker for angina

normal vitals
K+ = 6.0
WBC = 40,000
positive ketones
pH = 7.10 

what factors producing hyperkalemia

Answer 23

1) insulin deficiency
2) acidosis
3) beta blockers

Question 24

45 y/o woman with 3 day history of n/v/anorexia
stopped insulin
on beta blocker for angina

normal vitals
K+ = 6.0
WBC = 40,000
positive ketones
pH = 7.10 

what does she have?

Answer 24

diabetic with renal insufficiency = type IV RTA

possibly pseudohyperkalemia (WBC = 40k)

Question 25

45 y/o woman with 3 day history of n/v/anorexia
stopped insulin
on beta blocker for angina

normal vitals
K+ = 6.0
WBC = 40,000
positive ketones
pH = 7.10 

treatment?

Answer 25

1) EKG
2) insulin + rehydrate
3) monitor hypokalemia because total body K+ depleted

Question 26

50 y/o male hx alcohol abuse
2 weeks abd pain, n, v 
no diarrhea
on sodium bicarb 
dry muc membranes, decr skin turgor, no sweat 

potassium = 1.5
pH = 7.52

what is pathogenesis of hypokalemia

Answer 26

1) poor intake K+
2) vomiting
3) incr aldosterone due to volume depletion = weakness and ileus