ELECTROLYTES & SODIUM

Question 1

Total body water volume =

Answer 1

40 L, 60% body weight

Question 2

Intracellular fluid volume =

Extracellular fluid volume =

Answer 2

25 L, 40% body weight

15 L, 20% body weight

Question 3

Interstitial fluid volume =
Plasma volume =

Answer 3

12 L, 80% of ECF

3 L, 20% of ECF

Question 4

• requires energy to move ions across cellular membranes
• e.g.: ATPase-dependent Na+-K+ ion pumps

Answer 4

Active transport

Question 5

passive movement of ions across a membrane depends on size and charge of ion
• may be altered by physiologic and hormonal processes

Answer 5

Diffusion

Question 6

• physical property of a solution that is based on the concentration of solutes (expressed as millimoles)
per kilogram of solvent (w/w)

Answer 6

OSMOLALITY

Question 7

w/v
• inaccurate
> in cases of hyperlipidemia / hyperproteinemia for urine specimen

• presence of osmotically active substances (alcohol/mannitol)

Answer 7

Osmolarity

Question 8

Normal plasma osmolality
_______ of plasma H20
•osmoreceptors respond to small changes
•regulated by AVP and thirst

Answer 8

> 275 - 295 mOsm/kg

Question 9

URINE OSMOLALITY
• vary widely depending on water intake and collection circumstances

• decreased in:

• increased in:

Answer 9

• diabetes insipidus
• polydipsia

• SIADH
• hypovolemia

Question 10

ELECTROLYTES

Answer 10

•Sodium
•Potassium
•Chloride
•Calcium
•Magnesium
•Lactate
•Phosphate
•Bicarbonate

Question 11

• carry electric charge
• (+)
• (-)
• Exist in solid, liquid or gaseous environments

Answer 11

Ions

Question 12

(Na, Cl, K)

Answer 12

Volume and osmotic regulation

Question 13

(K, Mg, Ca)

Answer 13

• Myocardial rhythm and contractility

Question 14

(Mg, Ca, Zn)

Answer 14

• Cofactors in enzyme activation

Question 15

(Mg)

Answer 15

• Regulation of ATPase ion pumps

Question 16

(HCO3, K, CI)

Answer 16

• Acid-base balance

Question 17

(Ca, Mg)

Answer 17

• Blood coagulation

Question 18

(K, Ca, Mg)

Answer 18

• Neuromuscular excitability

Question 19

(Mg, PO4)

Answer 19

• Production and use of ATP from glucose

Question 20

‹ Monovalent cation

Answer 20

SODIUM ION

Question 21

• Most abundant cation in
the ECF

Answer 21

SODIUM ION

Question 22

SODIUM

• Accounts ___of all the ECF cations
• Large determinant of____

Answer 22

90%

plasma osmolality

Question 23

SODIUM ION REGULATION:

Answer 23

a) Intake of water in response to thirst

b) Excretion of water (affected by ADH in response to changes in either blood volume or osmolality)

c) Blood volume status (affects sodium excretion through aldosterone, angiotensin Il, and atrial natriuretic peptide)

Question 24

SODIUM ION REGULATION:
Primary active transport

Answer 24

• Na-K adenosine triphosphatase pump
• Na-K leak channels

Question 25

REFERENCE RANGES FOR TABLE 16-6 SODIUM Serum, plasma Urine (24 h) Cerebrospinal fluid

Answer 25

136-145 mmol/L 40-220 mmol/d, varies with diet 136-150 mmol/L

Question 26

Clinical Significance HYPONATREMIA • ____mmol/L • One of the most common electrolyte disorders

Answer 26

<135 mmol/L

Question 27

Hyponatremia • Probable cause

Answer 27

• ^ sodium loss • 1 water retention • Water imbalance

Question 28

Hypernatremia • Probable cause:

Answer 28

• Excess water loss • Decrease water intake • ^ sodium intake or retention

Question 29

HYPERNATREMIA •_______ mmol/L • Less common

Answer 29

>142 or >145

Question 30

CAUSES OF HYPONATREMIA INCREASED SODIUM LOSS

Answer 30

Hypoadrenalism Potassium deficiency Diuretic use Ketonuria Salt-losing nephropathy Prolonged vomiting or diarrhea Severe burns

Question 31

CAUSES OF HYPONATREMIA INCREASED WATER RETENTION

Answer 31

Renal failure Nephrotic syndrome Hepatic cirrhosis Congestive heart failure

Question 32

CAUSES OF HYPONATREMIA WATER IMBALANCE

Answer 32

Excess water intake SIADH Pseudohyponatremia SIADH, syndrome of inappropriate arginine vasopressin hormone secretion.

Question 33

WITH LOW OSMOLALITY

Answer 33

Increased sodium loss Increased water retention

Question 34

CLASSIFICATION OF HYPO-NATREMIA BY OSMOLALITY WITH NORMAL OSMOLALITY Increased nonsodium cations

Answer 34

Lithium excess Increased y-globulins-cationic (multiple myeloma) Severe hyperkalemia Severe hypermagnesemia Severe hypercalcemia Pseudohyponatremia Hyperlipidemia Hyperproteinemia Pseudohyperkalemia as a result of in vitro hemolysis

Question 35

WITH HIGH OSMOLALITY

Answer 35

Hyperglycemia Mannitol infusion

Question 36

HYPONATREMIA Treatment

Answer 36

o Directed at correction of the condition that caused either water loss or sodium loss in excess of water loss o fluid restriction and providing hypertonic saline and/ or other pharmacologic agents

Question 37

HYPONATREMIA Treatment

Answer 37

• Correcting severe hyponatremia too rapidly can cause cerebral myelinolysis and too slowly can cause cerebral edema

Question 38

CAUSES OF HYPERNATREMIA EXCESS WATER LOSS

Answer 38

Diabetes insipidus Renal tubular disorder Prolonged diarrhea Profuse sweating Severe burns

Question 39

CAUSES OF HYPERNATREMIA DECREASED WATER INTAKE

Answer 39

Older persons Infants Mental impairment

Question 40

CAUSES OF HYPERNATREMIA INCREASED INTAKE OR RETENTION

Answer 40

Hyperaldosteronism Sodium bicarbonate excess Dialysis fluid excess

Question 41

• Excess loss of water relative to sodium loss

Answer 41

HYPERNATREMIA

Question 42

HYPERNATREMIA • Diabetes Insipidus • Neurogenic: • Nephrogenic:

Answer 42

Deficiency of ADH Renal Tubules cannot respond to ADH

Question 43

• Patient drink large volumes of water, hypernatremia usually does not occur unless the thirst mechanism is also impaired

Answer 43

Huoernatremia

Question 44

• Decreased water intake • Commonly occurs in those persons Who may be thirsty out who are unable to ask for or obtain water (adults with altered mental status and infants)

Answer 44

HYPERNATREMIA

Question 45

HYPERNATREMIA • • • •

Answer 45

Increased sodium intake or retention Administration of hypertonic solutions of sodium Sodium bicarbonate Hypertonic dialysis solutions

Question 46

Treatment • Directed at correction of the underlying condition that caused the water depletion or sodium retention • Rapid correction can induce cerebral edema and death

Answer 46

HYPERNATREMIA

Question 47

URINE OSMOLALITY Diabetes insipidus (impaired secretion of AVP or kidneys cannot respond to AVP)

Answer 47

<300 mOsm/kg

Question 48

URINE OSMOLALITY Partial defect in AVP release or response to AVP Osmotic diuresis

Answer 48

300-700 mOsm/kg

Question 49

URINE OSMOLALITY Loss of thirst Insensible loss of water (breathing, skin) Gastrointestinal loss of hypotonic fluid Excess intake of sodium AVP, arginine vasopressin hormone.

Answer 49

>700 mOsm/kg

Question 50

• Neuropsychiatric

Answer 50

HYPONATREMIA

Question 51

• Nausea • Vomitting • Lethargy • Seizure • Coma • Respiratory depression • Muscular weakness • Headache • ataxia

Answer 51

HYPONATREMIA

Question 52

• Lethargy o Irritability • Restlessness • Seizures • Muscle twitching • Hyperreflexes • Difficult respiration • Increased thirst • Nausea

Answer 52

HYPERNATREMIA

Question 53

• Altered mental status

Answer 53

HYPERNATREMIA

Question 54

Less than 125 <120

Answer 54

HYPONATREMIA

Question 55

Above 160

Answer 55

HYPERNATREMIA