TBL 1 Flashcards
Normal K level
3.5-5
Normal Mg level
1.7-2.3
Normal plasma osmolality
275-290
Normal Na level
135-145
Normal Ca level
8.5-10
Normal Phos level
2.5-4.5
how does hypokalemia affect the EKG
depressed T wave, hyperpolarization
symptoms of hypokalemia
weakness, cramping, fatigue, myalgias
how does hyperkalemia affect the heart
peaked T wave, hypopolarization
what cations are inside the cell
potassium and magnesium
what cations are outside the cell
sodium and calcium
what is the most abundant cation
potassium
where is the primary site of potassium excretion
distal tubule
what regulates potassium excretion
aldosterone, delivery of sodium and water to distal tubule
what regulates the internal balance of potassium
insulin, catecholamines, acid-base
what does alkalosis do to potassium
moves it into the cell
what does acidosis do to potassium
moves it out of the cell
insulin stimulates ____
potassium uptake
catecholamines activate ____
Na-K-ATPase pump
what drugs cause hypokalemia by increasing sodium and water delivery to distal tubules
diuretics, aminoglycosides, penicillins
what drugs cause hyperkalemia
K-sparing diuretics, ACEi/ARB, NSAIDs, heparin, cyclo, tacro, trimethoprim, pentamidine
how can you treat hyperkalemia
calcium gluconate/chloride, insulin, albuterol, sodium bicarb, loop diuretics, potassium binders
what is the main site of magnesium reaborption
loop of henle
what are some drugs that cause hypomagnesemia
diuretics (loop bc Mg loop of henle), alcohol, aminoglycosides, ampho b, cisplatin, cyclo, tacro
what are some non-drug causes of hypomagnesemia
alcoholism, short gut syndrome, pancreatic insufficiency
what are some symptoms of hypomagnesemia
depressed T wave/prominent U wave (hypokalemia), positive chvostek/trousseua sign (hypocalcemia), tetany, convulsions, muscle cramps, neuromuscular irritability, tremor
how can you treat asymptomatic hypomagnesemia >1.0
oral supplementation, look out for diarrhea
how can you treat symptomatic hypomagnesemia <1.0
IV magnesium 2-4 g IV over 2-4 hours (causes vasodilation if given too fast)
what are some causes of hypermagnesemia
antacids, cathartics, renal failure
how can you treat hypermagnesemia
calcium chloride/gluconate, forced diuresis (saline w/ furosemide IV)
parathyroid hormone increases calcium _____
reabsorption
parathyroid hormone increases phosphate ____
excretion
parathyroid hormone activates ____
vitamin D
calcium _____ calcium reabsorption
decreases
_____ diuretics cause hypercalcemia
thiazide
when to administer phosphate binders
with meals
hypercalcemia effect on the heart
decreased QT interval, broadened T waves, first degree AV block
hypocalcemia effect on the heart
increased QT interval, AMI, CHF
symptoms of severe hypophosphatemia
decreased energy stores (ATP), decreased RBC 2,3-DPG concentration (decreases release of oxygen to peripheral tissues, may result in tissue hypoxia)
symptoms of acute hyperphosphatemia
deposition of Ca-Phos crystals, hypocalcemia
chronic symptoms of hyperphosphatemia
hypocalcemia, soft tissue calcification, secondary hyperparathyroidism, bone disease
neuromuscular symptoms of hypocalcemia
tetany, chvostek and trousseu signs, paresthesias, muscle cramps
dermatologic symptoms of hypocalcemia
hair loss, grooved, brittle nails, eczema
____ diuretics cause hyponatremia
thiazide
hyponatremia causes the brain to ____
swell
hypernatremia causes the brain to _____
shrink
what happens when you over-correct hyponatremia
osmotic demyelination
isovolemic hyponatremia can be caused by syndrome of inappropriate ___
ADH
isovolemic hyponatremia can be caused by _____
diabetes insipidus (central or nephrogenic)
central DI is caused by _____
decreased ADH secretion