Fluid, Electrolyte Disorders, and Acid-Base Imbalances

Question 1

Hypernatremia-

Answer 1

serum conc of sodium is > 135mEq/L

urine specific gravity- is >1.030 (high osmolality in urine d/t dehydration, low volume of urine)

Question 2

Hyponatremia-

Answer 2

serum conc of sodium is <135

urine specific gravity is < 1.010 (d/t water following salt and low salt in body means higher volume of water in urine)

Question 3

Potassium vs. Calcium-

Answer 3

Potassium affects the membrane potential.

Calcium affects the threshold potential.

Question 4

how do kidneys mediate sodium excretion and water excretion?

Answer 4

sodium excretion-> through aldosterone.

water excretion-> through ADH.

Question 5

hypokalemia-

Answer 5

Diagnostic findings when serum concentration is < 3.5 mEq/L and Hypercalcemia (increased ECF moves into ICF, making the charge more positive, increasing the threshold potential and increasing the space between threshold and membrane potential-> requiring stronger stimulus).

HYPOkalemia-> HYPERPOLARIZED cell (decreased excitability, AP is initiated slower, requires stronger stimulus).

Question 6

how does insulin affect glucose/potassium?

Answer 6

insulin administration increases glucose and potassium entry into cell, increasing risk for HYPOKalemia.

Question 7

What does calcium affect?

Answer 7

Threshold potential!

Question 8

Hypokalemia- <3.5

Answer 8

Affects membrane potential. Which causes K+ to move from ICF to ECF, lowering the charge and causing HYPERPOLARIZATION -> delayed contraction, conduction, lethargy, smooth muscle weakness, smooth muscle atony.

Common in ALKALOSIS.

Question 9

Hyperkalemia is >5

Answer 9

Affects membrane potential. Causes K+ to move from ECF to ICF-> making membrane potential to be more positive-> HYPOPOLARIZATION-> increased excitability, hyperreflexia, tingling of lips, increased intestinal cramping and diarrhea.

Common in ACIDOSIS.

Question 10

Hypocalcemia <8.5

Answer 10

Calcium affects threshold potential. Causes Ca+ to move from ICF to ECF, reducing the threshold potential to become more negative-> HYPOPOLARIZATION-> increased excitability. Chvostek’s sign (face) and Trousseau’s sign (hand), tetany, hyperactive bowel sounds.

Occurs in ALKALOSIS.

Question 11

Hypercalcemia >10.5

Answer 11

Affects threshold potential. Ca+ moves from ECF to ICF-> making the threshold potential more positive,-> HYPERPOLARIZATION-> fatigue, lethargy, anorexia, nausea, and constipation.

Common in ACIDOSIS.

Question 12

Hypertonic alterations are usually caused by?

Answer 12

Loss of free water or failure to replace water loss.

may be related to increased sodium intake.

Question 13

define hydrostatic pressure-

Answer 13

hydrostatic pressure tends to force water OUT of a compartment.

Question 14

is the hydrostatic pressure greater in the intravascular compartment or interstitial compartment?

Answer 14

Intravascular- due to the heart putting pressure and pumping out water!

Question 15

define oncotic pressure-

Answer 15

oncotic pressure is the pressure that brings water IN.

Question 16

T/F- the amount of water leaving the capillary for the interstitium slightly exceeds the amount leaving the interstitium for the capillary

Answer 16

True. Why? It’s because the few drops left behind are usually taken up by the lymphatic vessels in the interstitial compartment and return it to the intravascular compartment.

Question 17

what are the causes of edema?

Answer 17

increased capillary venous hydrostatic pressure, decreased capillary oncotic pressure, lymphatic obstruction/dysfunction, increased capillary permeability (d/t inflammation) and/or sodium and water retention (from renin-aldosterone system that increases hydrostatic pressure)

Question 18

hardness or softness of edema is caused by-

Answer 18

the amount of protein in the fluid.

a lot of protein in fluid-> non-pitting edema.
low amount of protein in fluid-> pitting edema.

Question 19

non-pitting edema is caused by

Answer 19

increased amount of proteins in fluid due to increased capillary permeability and lymphatic obstruction

Question 20

pitting edema is caused by

Answer 20

low amount of proteins in fluid caused by increased capillary venous hydrostatic pressure and decreased capillary oncotic pressure.

Question 21

Aldosterone causes what?

Answer 21

Sodium and Bicarb retention and increased H+ and K+ excretion .