Electrolytes

Question 1

what does PANIC stand for

Answer 1

positive anode negative is cathode

Question 2

osmotic pressure

Answer 2

governs movement of water across semi-permeable membranes in response to solute concentration
Glomeruli in kidneys, capillary vessels

Question 3

osmosis

Answer 3

movement of water through a selectively permeable membrane in order to equalize solute concentration
Moves from area of low concentration to area of high concentration

Question 4

Osmolality

Answer 4

A physical property of a solution that is based on the concentration of solutes per kilogram solvent

Question 5

Sodium is

Answer 5

primary cation in extracellular fluid

Question 6

sodium reference interval urine and serum

Answer 6

135-145 mmol/L serum
40-220 urine

Question 7

Hyponatremia

Answer 7

serum sodium less than 135mmol/L caused by increased loss, increased water retention or water imbalance

Question 8

hyponatremia symptoms

Answer 8

125-130 is primarily GI
<125 is more severe neuropsychiatric symptoms like nausea, vomiting, lethargy and ataxia

Question 9

hypernatremia

Answer 9

increased serum Na. Excess water loss, decreased intake and increase Na intake

Question 10

hypernatremia symptoms

Answer 10

CNS, altered mental status, lethargy, irritability, restlessness, seizures, muscle twitching, nausea and vomiting

Question 11

Measurement of urine osmolality to determine hypernatremia cause

Answer 11

Renal water loss = low osmolality
Extrarenal water loss = osmolality is increased

Question 12

Potassium

Answer 12

Primary intracellular cation. Concentration is maintained by ATPase pumps. Has major effects on skeletal and heart muscle

Question 13

Potassium reference interval

Answer 13

3.5-5.1 mmol/L (serum)

Question 14

Is there a difference between serum and plasma/whole blood potassium?

Answer 14

yes, serum is 0.2-0.5mmol/L higher. because of hemolysis

Question 15

Hypokalemia

Answer 15

decreased K+ concentration caused by diuretics, GI loss, renal loss

Question 16

hypokalemia symptoms

Answer 16

weakness, fatigue, muscle weakness

Question 17

Hyperkalemia

Answer 17

increased K+ concentration, usually in people with an underlying condition like renal insufficiency, diabetes or metabolic acidosis

Question 18

hyperkalemia symptoms and treatment

Answer 18

Symptoms: muscle weakness, tingling, numbness and mental confusion, cardiac arrythmias and possible cardiac arrest.
Treatment: IV K+ solution

Question 19

Ion selective electrode

Answer 19

membrane permeability only to select anions/cations. Potential is produced proportional to ion concentration

Question 20

Chloride

Answer 20

primary extracellular anion excreted at kidneys

Question 21

chlorine reference interval

Answer 21

98-107mmol/L

Question 22

common measurement of chloride

Answer 22

ISEs

Question 23

Chloride sweat analysis

Answer 23

differential diagnosis for cystic fibrosis. It is usually done with newborn screening.
Steps:
1. sweat stimulation
2. sweat collection (30 min)
3. sweat analysis

Question 24

Bicarbonate HCO3 measurement

Answer 24

measure via production of carbon dioxide following acidification (ISE) or alkalinization

Question 25

Bicarbonate reference range

Answer 25

23-29mmol/L

Question 26

Anion gap

Answer 26

difference between the sum of the measured cations and the sum of the measured anions

Question 27

anion gap reference range

Answer 27

7-16mmol/L

Question 28

Elevated AG causes

Answer 28

uremia/renal failure, ketoacidosis, methanol, ethanol, ethylene glycol, salicylate poisoning, lactic acidosis, instrument error

Question 29

low AG

Answer 29

rare but seen in hypoalbuminemia and severe hypercalcemia

Question 30

Plasma/urine osmolality equation

Answer 30

mOsmol/kg = 1.86 [Na+] + glucose/18 + urea/2.8 + 9

Question 31

Osmolal gap reference interval

Answer 31

5-10 mOsm/kg

Question 32

osmolal gap equation

Answer 32

measured osmolality – calculated osmolality

Question 33

What does the osmolal gap tell us

Answer 33

tells us about the presence of exogenous osmotic substances, and measures osmolality with freezing point depression or vapor pressure

Question 34

what causes increased osmolal gap

Answer 34

ethylene glycol, methanol, isopropanol, lactate, beta hydroxybutyrate