T2: Water and Electrolyte Balance Part 2

Question 0

Sodium Reference Range

Answer 0

136-145 mEq/L

Question 1

Most common cause of water intoxication

Answer 1

Extracellular fluid gain caused by syndrome of inappropriate ADH secretion (SIADH)

Question 2

Four functions of sodium

Answer 2

1 maintain normal H2O distribution
2 maintain normal osmotic pressure
3 neuromuscular processes
4 acid-base balance

Question 3

Sodium is a major extracellular ________

Answer 3

cation

Question 4

Three renal processes by which normal levels of sodium are maintained in the body

Answer 4

1 Kidneys-filtered in glomeruli; reabsorption in the PCT, Loops of Henle, and DCT
2 Aldosterone controls Na in DCT
3 BNP gets rid of Na

Question 5

Depletional hyponatremia causes ________ hyponatremia

Answer 5

absolute

Question 6

two general causes of depletional hyponatremia

Answer 6

1 renal losses

2 non-renal losses

Question 7

Two general causes of renal losses in depletional hyponatremia

Answer 7

1 diuretic use

2 hypoaldosteronism

Question 8

Two general causes of non-renal losses in depletional hyponatremia

Answer 8

1 GI loss

2 skin loss

Question 9

Dilutional hyponatremia is a _________ hyponatremia

Answer 9

relative

Question 10

Two general causes of dilutional hyponatremia

Answer 10

1 SIADH

2 Hyperglycemia

Question 11

Why does SIADH and hyperglycemia lead to increased water volume in dilutional hyponatremia?

Answer 11

1 ADH secreted all the time, which causes us to retain H2O diluting Na
2 increased glucose in urine causes it to be diluted with H2O

Question 12

Two general causes of pseudohyponatremia

Answer 12

1 hyperlipidemia

2 hyperproteinemia

Question 13

Why does hyperlipidemia and hyperproteinemia cause low sodium results in pseudohyponatremia?

Answer 13

Displaces some H2O, picks up more lipids or protein than plasma H2O

Question 14

Three general causes of hypernatremia due to water loss

Answer 14

1 GI losses
2 Excessive sweating
3 Diabetes insipidus

Question 15

Two general causes of hypernatremia due to sodium gain

Answer 15

1 ingestion or infusion of Na

2 Hyperaldosteronism

Question 16

Reference Range of potassium

Answer 16

3.5-5.0 mEq/L

Question 17

Two functions of potassium

Answer 17

1 regulation of many cellular processes

2 neuromuscular excitation (heart)

Question 18

Why does insulin cause hypokalemia?

Answer 18

too much glucose and potassium

Question 19

Why does alkalosis compensation cause hypokalemia?

Answer 19

Need more acid in bloodstream so RBCs push H ions into blood and take up more K

Question 20

Four general caues of hypokalemia due to renal loss

Answer 20

1 hyperaldosteronism
2 diuretic theory
3 licorice ingestion

Question 21

Three general causes of hypokalemia due to excessive gastrointestinal loss

Answer 21

1 vomiting
2 diarrhea
3 laxative abuse

Question 22

Three general causes of hyperkalemia due to increased in vivo cell lysis

Answer 22

1 cellular trauma
2 cellular injury
3 in vivo hemolysis

Question 23

Two general causes of hyperkalemia due to altered cellular uptake

Answer 23

1 compensation for acidosis (H taken into cell, K pushed out=electroneutrality)
2 insulin deficiency

Question 24

Two general causes of hyperkalemia due to imapired renal excretion

Answer 24

1 renal insufficiency or failure

2 hypoaldosteronism

Question 25

Reference Range of Chloride

Answer 25

99-109 mEq/L

Question 26

Chloride is a major extracellular _____

Answer 26

anion

Question 27

three functions of chloride

Answer 27

1 maintains H2O balance
2 maintains osmotic pressure
3 Acid-base balance with “chloride shift”

Question 28

Three general causes of hypochloremia and associated conditions

Answer 28

1 GI Losses- prolonged vomiting, nasogastric suctioning
2 Burns-tissue trauma
3 renal losses-diuretic therapy, compensation for metabolic acidosis

Question 29

Two general causes of hyperchloremia and associated conditions

Answer 29

1 dehydration
2 renal tubular acidosis-Na gain
3 compensation for metabolic alkalosis

Question 30

REMEMBER: Cl levels altered in same direction as Na = ______ _____

Answer 30

water imbalance

Question 31

REMEMBER: Cl levels not proportional to Na = _____ ______ ______

Answer 31

Acid-base imbalance

Question 32

Clinical usefulness of sweat chloride measurements

Answer 32

sweat induced by pilocarpine iontophoresis; cystic fibrosis detected if >60 mEq/L and normal if <40 mEq/L