Fluid and Electrolytes Part I

Question 1

How much fluid is gained from enteral liquids?

Answer 1

500-1500 mL/day

Question 2

How much fluid is gained from enteral solids?

Answer 2

500-1000 mL/day

Question 3

How much fluid is gained from metabolism?

Answer 3

300 mL/day

Question 4

How much sensible fluid is lost daily?

Answer 4

1.0 - 1.5 L

Question 5

What are sensible fluids?

Answer 5

Urine

Stool

Question 6

How much insensible fluids are lost daily?

Answer 6

< 1.0 L

Question 7

What are insensible fluids?

Answer 7

Lungs
Sweat
Fever

Question 8

What are other ways to lose fluids?

Answer 8

Burns

Nasogastric tube

Question 9

What is the calculation for daily maintenance fluid requirements?

Answer 9

1500 mL + 20 mL/kg for every kg > 20kg

Question 10

What is the average adult daily fluid requirement?

Answer 10

30 - 35 mL/kg

Question 11

What are the sx of hypovolemia?

Answer 11

Acute weight loss
Tachycardia, orthostasis
Dry mouth, dry skin
Decreased skin turgor
BUN:SCr > 20:1

Question 12

What are the sx of hypervolemia?

Answer 12

Acute weight gain

Edema: pulmonary, extremities, ascites, anascara

Question 13

What is normal serum osmolality?

Answer 13

275 - 290 mOsm/kg

Question 14

What is normal urine sodium?

Answer 14

25 - 250 mEq/L

Question 15

What is normal urine osmolality?

Answer 15

100 - 900 mOsm/kg

Question 16

What is the primary cause of hyponatremia?

Answer 16

Disorder of water balance

Question 17

What hormone is hyponatremia associated with?

Answer 17

Vasopressin

Question 18

What are the classifications for hyponatremia?

Answer 18

Mild: 130 - 135
Moderate: 125 - 129
Profound: < 125
Acute: < 48 hours
Chronic: > 48 hours

Question 19

What is the clinical presentation of hyponatremia?

Answer 19

Nausea
Malaise
HA
Lethargy
Restlessness
Disorientation
Seizures
Coma
Depressed reflexes

Question 20

What are the sx of moderately severe hyponatremia?

Answer 20

Nausea w/o vomiting
Confusion
HA

Question 21

What are the sx of severe hyponatremia?

Answer 21

Vomiting
Cardiorespiratory distress
Abnormal and deep somnolence
Seizures
Coma (Glasgow Coma Scale = 8)

Question 22

What is the treatment for a patient that has hypovolemic hyponatremia that is asymptomatic and/or serum Na > 120?

Answer 22

Isotonic fluids

Question 23

What is the treatment for a patient that has hypovolemic hyponatremia that is symptomatic and/or serum Na < 120?

Answer 23

Hypertonic fluids

Question 24

What is the goal for serum increase rate?

Answer 24

< 10 mEq/L in 24 hours

Question 25

What happens if the sodium correction rate is too rapid?

Answer 25

Risk of central pontine demyelination

Question 26

What is central pontine demyelination?

Answer 26

Too rapid correction of sodium in hyponatremia would cause the extracellular fluid to be relatively hypertonic. Free water would then move out of the cells. This leads to paralysis.

Question 27

What is another name for euvolemic hyponatremia?

Answer 27

SIADH

Question 28

What does SIADH stand for?

Answer 28

Syndrome of Inappropriate Anti-Diuretic Hormone

Question 29

What are the causes of SIADH?

Answer 29

Lung cancer Pituitary tumor Drugs (carbamazepine, vincristine, SSRIs) **Absolute increase in body water

Question 30

What is the gold standard treatment for SIADH?

Answer 30

Fluid restriction: < 1 L/d x several days

Question 31

What are treatment options for SIADH?

Answer 31

Fluid restriction Vasopressin receptor antagonists Demeclocycline

Question 32

How do vasopressin receptor antagonists work?

Answer 32

Works at the collecting ducts of the nephron and increases free water excretion

Question 33

What are the vasopressin receptor antagonists?

Answer 33

Conivaptan | Tolvaptan

Question 34

What is demeclocycline?

Answer 34

ADH receptor antagonist (delayed onset)

Question 35

What are the causes of hypervolemic hyponatremia?

Answer 35

Renal failure Liver failure Heart failure Nephrotic syndrome

Question 36

What is the treatment of hypervolemic hypernatremia?

Answer 36

Sodium AND fluid restriction Sodium 1 - 2 g/d Fluids < 1 L/d

Question 37

What are the sx of hypernatremia?

Answer 37

``` Lethargy Weakness Confusion Restlessness Irritability ```

Question 38

What are the signs of hypernatremia

Answer 38

Consistent with volume status | Increased or decreased output of concentrated or dilute urine - dependent on cause

Question 39

What is the pathophysiology of hypovolemic hypernatremia?

Answer 39

Loss of hypotonic fluids (sweat, urine, diarrhea) | Patient not able to replenish fluid

Question 40

What types of fluids do we give hypovolemic hypernatremia?

Answer 40

Hypotonic fluids to correct water deficit (1/2 NS or D5W) | If patient is hypotensive use NS

Question 41

What is the risk if the sodium correction is too fast in hypernatremia?

Answer 41

Risk of cerebral edema

Question 42

What is the goal serum sodium decrease rate?

Answer 42

< 12 mEq/L in 24 hours

Question 43

What is the cause of euvolemic hypernatremia?

Answer 43

Diabetes Insipidus (DI) - decrease in ADH secretion or a decrease in renal response to ADH

Question 44

What is the cause of central DI?

Answer 44

Familial Neuosurgery Head trauma CNS malignancy

Question 45

What is the treatment for central DI?

Answer 45

Desmopressin (via intranasal route)

Question 46

What are the types of DI?

Answer 46

Central | Nephrogenic

Question 47

What are the causes of nephrogenic DI?

Answer 47

``` Lithium toxicity Hypercalcemia Hypokalemia Foscarnet Demeclocycline ```

Question 48

What are the treatments of nephrogenic toxicity?

Answer 48

Remove/treat underlying cause Sodium restriction < 2 g/d Thiazide diuretic

Question 49

What is the cause of hypervolemic hypernatremia?

Answer 49

Sodium overload - caused by excess hypertonic fluid or excess intake of sodium

Question 50

What is the treatment of hypervolemic hypernatremia?

Answer 50

Loop diuretics