Week 2: Potassium and Magnesium (Zhang)

total body water is distributed primarily into two compartments which are what

1. intracellular compartment

2. extracellular compartment or extracellular fluid

primarily determined by the concentration of potassium and its accompanying anions (mostly organic and inorganic phosphates) is what

intracellular compartment

Sodium and its accompanying anions (chloride and bicarbonate) comprise more than 90% of the total osmolality of the ECF is what .

extracellular compartment or extracellular fluid

intracellular compartment is what perfect of TBW

60%

extracellular compartment is what percent of TBW

40%

what is the normal level of potassium

3.5-5.0

the most abundant cation in the body, with estimated total-body stores of 3,000 to 4,000 mEq (3,000 to 4,000 mmol) is what

potassium

The sodium-potassium adenosine triphosphatase (Na⁺-K⁺-ATPase) pump located in the cell membrane is responsible for the compartmentalization of potassium. This pump is an active transport system that maintains increased

intracellular stores of potassium by transporting sodium out of the cell and potassium into the cell at a ratio of 3:2.

(t or f)

true

what drugs causes hypokalemia

thaizides

loop diuretics

which intracellular shifts cause hypokalemia

excess catecholamines

insulin overdose

which trascellular shift causes hypokalemia

beta 2 receptor agonists

insulin overdose

enhanced renal excretion

loop and thiazide diuretic administration is pathophysiology of what

hypokalemia

pharmacology for hypokalemia

1. potassium supplements

2. potassium sparing diuretics

what are the potassium supplements formulated with salts,

chloride, phosphate, bicarbonate

in the collecting duct and distal tubule is what drugs

• aldosterone antagonism

spironolactone and eplerenone

inhibition of aldosterone sensitive sodium channels are what drugs

amiloride and triamterene

1.potassium intake exceeds excretion (true hyperkalemia)

     (i.e., elevated total-body stores)

2.  the transcellular distribution of potassium is disturbed

     (i.e., normal total-body stores).

is when hyperkalemia happens

primary causes of hyperkalemia

• impaired potassium excretion

  • AKI or stage 4 to 5 CKD

  • drug induced hykalemia

  • tubular unresponsiveness to aldosterone

what are the drug induced hyperkalemia

ACE

ARBs

NSAIDs

direct renin inhibitors

potassium sparing diuretics

what are all the primary causes of hyperkalemia

1. increased potassium intake

2. impaired potassium excretion

3. redistribution of potassium into the extracellular space

   metabolic acidosis, diabetes mellitus, or lactic acidosis.

what is the drug induced redistribution of potassium

b-blockers

what is the normal level of magnesium

1.6-2.4

magnesium is principally distributed in what

bone and muscle

predominantly intracellular distribution is what

magnesium

the majority of magnesium int he extracellular fluid is in the ionized form as only 20% is bound to serum proteins (t/f)

true

• reduce intestinal absorption of magnesium

• increased renal excretion of magnesium

is etiology and pathophysiology of what

hypomagnesemia

decreased intestinal absorption as a result of small bowel disease is the most common cause of what

hypomagnesemia

which is present in more than 50% of cases of clinically significant hypokalemia, contributes to the development of hypokalemia because it reduces the intracellular potassium concentration and promotes renal potassium wasting is what

hypomagnesemia

hypomagnesemia → hypokalemia leads to what

cardiac arrhythmia

hypomagnesemia → hypocalcemia leads to what

neuromuscular irritability

In patients with concomitant hypokalemia and hypomagnesemia, it is imperative to correct the hypomagnesemia before the hypokalemia. (t/f)

true

Because absolute magnesium excretion decreases as GFR declines, serum magnesium concentrations tend to increase in patients with moderate to severe CKD is what

hypermagnesemia

normal serum concentration range for potassium is what

3.5-5

the intracellular potassium concentration is usually aprox what

150

what is responsible for compartmentalization

Na+-K+-ATPase

different formulations of potassium supplement GI intolerance

wax matrix extended release tablets > controlled release micro encapsulated tablets

primary cause of hypokalemia

• loop and thiazide diuretic administration

• excessive load of potassium rich GI fluid as a result of diarrhea or/and vomitting

dryg induced hypokalemia is what

beta 2 agonists, insulin overdose, high dose of penicillin

primary cause of hyperkalemia

• increase potassium intake

• decreased potassium excretion

• tubular unresponsiveness to aldosterone

• redistribution of potassium into the extracellular space

what are the drug induced hyperkalemia

ACE

ARBs

direct renin inhibitors

potassium sparing diuretics

NSAIDs

beta blockers

hypomagnesemia contributes to the development of what

hypokalemia

it is imperative to correct the hypo magnesemia before what

hypokalemia

in collecting tubule Na is which hormone

aldosterone

what are the possible mechanisms of potassium sparing diuretics

• aldosterone antagonism

  • inhibition of aldosterone sensitive sodium

drug induced of hyperkalemia is what drug

b-blocker

beta2 agonists, insulin overdose, high dose penicillin is drug induced for what

hypokalemia

ACE, ARBs, direct renin inhibitor, potassium sparing diuretics, NSAIDs, and beta blockers are drug induced for what

hyperkalemia