Electrolytes and Imbalances

Question 1

What 7 electrolytes are included in the “fish bone”?

Answer 1

(1) Na+
(2) Cl-
(3) BUN
(4) blood glucose
(5) K+
(6) HCO3-
(7) SCr

Question 2

What is osmolality?

Answer 2

Concentration of solutes/electrolytes per liter of solution/water

Question 3

What does increased serum osmolality suggest?

Answer 3

Volume depletion → inc [ ] of electrolytes

Question 4

What does decreased serum osmolality suggest?

Answer 4

Volume overload → dilution of electrolytes

Question 5

What is water regulation primarily controlled by?

Answer 5

Secretion of ADH

Question 6

What is the mechanism of water regulation in the body?

Answer 6

Blood volume decreases→ pituitary releases ADH→ ADH tells the kidney to hold onto water

Question 7

What is third spacing?

Answer 7

When there is a large volume of fluid from the intravascular compartment that shifts into an interstitial space

Question 8

What are colloids?

Answer 8

Solutions that don’t cross the cell membrane b/c they’re too big→ remain in the intravascular compartment and expand the intravascular volume and draw fluid from extravascular spaces via higher oncotic pressure

Question 9

What are crystalloids?

Answer 9

Solutions that contain small molecules that easily pass through the cell membrane and inc fluid volume in both interstitial and intravascular spaces

Question 10

What is an isotonic solution?

Answer 10

Same concentration of solutes in blood so cell content stays the same (when you give, it doesn’t change the water content of the cell)

Question 11

What is a hypotonic solution?

Answer 11

Same concentration of solutes in blood so cell content stays the same (when you give, it doesn’t change the water content of the cell)

Question 12

What is a hypertonic solution?

Answer 12

Higher [ ] of solutes so solutions pull fluid from the cells-shrink

Question 13

What are 3 examples of isotonic IV fluids?

Answer 13

(1) normal saline 0.9% NaCl
(2) lactated ringer
(3) ringers solution

Question 14

When do you give normal saline?

Answer 14

When the extracellular volume is low (ex: dehydration, vomiting/diarrhea, shock, hemorrhage, etc.)

Question 15

What isotonic solution most closely mimics the blood and plasma concentration?

Answer 15

Lactated ringers

Question 16

What 5 electrolytes do lactated ringers contain?

Answer 16

(1) sodium (2) potassium (3) chloride (4) calcium (5) bicarb-lactate

Question 17

What pts will benefit greatly from lactated ringers?

Answer 17

Pts requiring electrolyte replacement

Question 18

What 4 types of pts should you avoid giving lactated ringers to?

Answer 18

(1) lactic acidosis
(2) liver disease
(3) renal impairment
(4) pH >7.5

Question 19

What 4 electrolytes are in ringers solution?

Answer 19

(1) sodium
(2) chloride
(3) potassium
(4) calcium

Question 20

In what 2 situations should you give ringers solution?

Answer 20

(1) when giving lactate is c/i

(2) in lactic acidosis

Question 21

What is special about dextrose 5%?

Answer 21

It is isotonic, but when metabolized it becomes hypotonic and causes fluid to shift into cells (it also provides minimal cals while pt is NPO)

Question 22

When are hypotonic IV fluids used?

Answer 22

Used to tx pts w/conditions causing intracellular dehydration (hypernatremia, DKA, hyperosmolar hyperglycemia)

Question 23

What 3 things is sodium important for?

Answer 23

(1) regulates transmission of impulses in nerve and muscle fibers
(2) main factor in determining volume of extracellular space
(3) helps maintain acid-base balance

Question 24

What are 5 conditions associated with hyponatremia?

Answer 24

(1) acute illness
(2) HF
(3) cirrhosis
(4) renal failure
(5) aggressive IV fluid administration

Question 25

Excess of what can cause hyponatremia and what is the mechanism leading to hyponatremia?

Answer 25

Hyperglycemia→ high serum sugar→ cells release water → sodium gets diluted while body gets overloaded with water (body is trying to dilute the sugar by inc water, but that dilutes salt too causing hyponatremia)

Question 26

What 3 things lead to hyponatremia?

Answer 26

(1) syndrome of inappropriate ADH (2) chronic alcoholics (3) water intoxication-marathon runners, drugs

Question 27

How do you tx hyponatremia?

Answer 27

Tx depending on cause: if fluid overload→ fluid restriction, if severe and symptomatic→ fluid restriction + sodium replacement

Question 28

Why do you want to correct hyponatremia slowly?

Answer 28

B/c of risk of Central Pontine Myelinolysis (CPM)- an osmotic demyelinating injury

Question 29

What are 5 signs of hypernatremia?

Answer 29

(1) fever (2) sweating (3) vomiting (4) diarrhea (5) primary hypodipsia

Question 30

What are the 2 mechanisms of diabetes insipidus causing hypovolemic hypernatremia?

Answer 30

(1) dec secretion of ADH (2) inc renal resistance to ADH (cannot [ ] urine); you’re peeing out the water, but Na+ is staying

Question 31

What happens in hyperaldosteronism leading to hypernatremia?

Answer 31

Problem w/adrenals (usually a benign tumor) → excess production of aldosterone → sodium and water inc and potassium dec

Question 32

What 2 things do you tx hypovolemic hypernatremia pts with?

Answer 32

(1) IV isotonic solution (0.9% saline) | (2) limit salt intake

Question 33

What do you tx euvolemic hypernatremia pts with?

Answer 33

IV hypotonic fluids (D5W)

Question 34

What 2 things do you tx hypervolemic hypernatremia pts with?

Answer 34

(1) D5W | (2) diuretics

Question 35

What are the 3 most common causes of dyskalemia?

Answer 35

(1) medications: ACE inhib- Lisinopril, K+ sparing diuretics (Spironolactone), OCP- Yaz (2) renal dysfunction (3) dietary intake

Question 36

What 3 categories of medications cause hypokalemia?

Answer 36

(1) diuretics (2) insulin (3) beta adrenergic agents

Question 37

What are 3 findings on an EKG of hypokalemia?

Answer 37

(1) flat T wave (2) ST segment depression (3) formation of U waves

Question 38

How do you tx mild hypokalemia?

Answer 38

Oral KCl

Question 39

How do you tx severe hypokalemia?

Answer 39

IV KCl

Question 40

How do you tx hypokalemia + low Mg+?

Answer 40

Mg+ first THEN K+ (b/c must be cardioprotective first before fixing K+)

Question 41

What 3 medications cause hyperkalemia and what is a common complication that leads to hyperkalemia?

Answer 41

(1) ACE inhib- Lisinopril (2) ARBs- Losartan (3) Aldosterone antag- Spironolactone kidney failure/insufficiency

Question 42

What are 2 clinical manifestations of hyperkalemia?

Answer 42

(1) muscle weakness | (2) paresthesias

Question 43

What are 3 findings on an EKG of hyperkalemia?

Answer 43

(1) tall or peaked T waves (2) widened/bizarre QRS (3) flat P waves

Question 44

What is the first agent to have on board in tx of hyperkalemia?

Answer 44

IV calcium (gluconate or chloride)- cardioprotective!!

Question 45

What tx helps move excess K+ into the cells?

Answer 45

IV hypertonic glucose + regular insulin

Question 46

What 4 processes require Ca+?

Answer 46

(1) blood coagulation (2) nerve excitability (3) development of action potentials for muscle contraction (4) osteoclast activity

Question 47

What are 5 common causes of hypocalcemia?

Answer 47

(1) parathyroid disease (2) thyroid disease (3) thyroid or parathyroid-ectomy (4) chronic renal failure (5) Vit D deficiency

Question 48

A deficiency of what can cause pseudohypocalcemia?

Answer 48

Albumin

Question 49

What are 2 classic physical findings of hypocalcemia?

Answer 49

(1) Chvostek sign: facial spasm following the percussion of the facial nerve (2) Trousseau’s sign: spasm of the hand elicited by inflation of a BP cuff

Question 50

What is a finding on an EKG of hypocalcemia?

Answer 50

Prolonged QT interval

Question 51

What is the tx of asymptomatic hypocalcemia? Symptomatic?

Answer 51

Asymptomatic: oral Ca+ Symptomatic: IV Ca+

Question 52

What are the 3 most common causes of hypercalcemia?

Answer 52

(1) hyperparathyroidism (2) bone malignancy (multiple myeloma) (3) prolonged immobilization