PHRM 825: Fluids and Electrolytes - Electrolytes - Na+ Flashcards

1
Q

Sodium goal concentration

A

135-145 mEq/L (remember 140)

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2
Q

Sodium is primarily an _______ cation

A

extracellular

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3
Q

Sodium is needed to maintain _______

A

cellular integrity

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4
Q

Sodium maintains ____ gradient and regulates ______ throughout the different compartments

A

Osmolar; fluid homeostasis

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5
Q

What is the most common electrolyte disturbance in hospitalized patients

A

Hyponatremia

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6
Q

Hyponatremia has significant ________

A

morbidity and mortality

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7
Q

Osmolarity calculation

A

Osm = (2*Na) + (BUN/2.8) + (Glucose/18)

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8
Q

Osmole gap (OG) exists when

A

The difference between the measured and calculated is greater than 15

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9
Q

OG is the presence of

A

Unidentified particles

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10
Q

Osmole gap calculation

A

Osm serum - Calculated Osm

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11
Q

Types of hyponatremia

A

Pseudohyponatremia, Hypertonic hyponatreamia, hypotonic hyponatremia

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12
Q

Types of hypotonic hyponatremia

A

Hypovolemic hyponatremia, isovolemic hyponatremia, hypervolemic hyponatremia

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13
Q

Pseudohyponatremia is ______

A

isotonic

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14
Q

Pseudohyponatremia definition

A

When extreme elevation of lipids and proteins increase the total plasma volume which leads to a dilution effect so the sodium appears low

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15
Q

Pseudohyponatremia calculated Osm is _____ which leads to an ____

A

Los; OG

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16
Q

Hypertonic hyponatremia is most frequently seen with _______

A

elevated blood glucose

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17
Q

Serum sodium falls by ______ for each _______ incremental increase in BG >______

A

1.6 mEq/L; 100mg/dL; 100 mg/dL

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18
Q

Equation for corrected sodium

A

Corrected Na+ = Na serum + 1.6[(BG-100)/100]

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19
Q

Hypotonic hyponatremia accounts for what percentage of all hyponatremias

A

> 90%

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20
Q

Most important step when assessing for hypotonic hyponatremia is to clinically assess the patient’s _____

A

ECF volume

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21
Q

Hypovolemic hypotonic hyponatremia is characterized by a decrease in both total body _____ and _____

A

Water and Na+

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22
Q

Renal causes of hypovolemic hypotonic hyponatremia

A
  • Diuretics/excessive diuresis
  • Adrenal insufficiency
  • Salt losing nephropathy
  • Cerebral salt wasting
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23
Q

When hypovolemic hypotonic hyponatremia is caused by the renal system, urine sodium levels will be ____

A

> 20 mEq/L

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24
Q

Non-renal causes of hypovolemic hypotonic hyponatremia

A
  • Blood loss/hemorrhage
  • Skin losses (burns, sweat, wounds)
  • GI losses (vomiting, diarrhea, suction)
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25
Q

Causes of isovolemic hypotonic hyponatremia

A
  • Adrenal insufficiency (glucocorticoid deficiency)
  • Hypothyroidism
  • Psychogenic polydipsia
  • SIADH
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26
Q

Meaning of SIADH

A

Syndrome of Inappropriate Antidiuretic hormone release

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27
Q

What is the most common cause of isovolemic hypotonic hyponatremia

A

SIADH

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28
Q

Characteristics of SIADH

A

Water intake exceeds capacity of the kidneys to excrete water

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29
Q

Causes of SIADH

A

Tumors, CNS disorders (stroke, head trauma, meningitis, etc), Drugs

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30
Q

Usual urine Osm and Na+ in someone with SIADH

A

Osm > 100 mOsm/kg

Na > 20-30 mEq/L

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31
Q

How is SIADH treated?

A
  • Remove underlying cause if possible
  • First line: free H2O restriction
  • Vaptans (if 24-48 hrs of free h2o restriction fails)
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32
Q

Hypervolemic hypotonic hyponatremia is caused when

A

The total body Na+ is increased but the TBW is increased even more

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33
Q

Hypervolemic hypotonic hyponatremia is characterized by

A

Expanded ECF volume and edema

34
Q

Hypervolemic hypotonic hyponatremia can be caused by

A
  • Cirrhosis
  • Heart failure
  • Kidney failure
  • Nephrotic syndromes
35
Q

Clinical presentation of hypotonic hyponatremia

A

Mostly asymptomatic

36
Q

Clinical presentation of hypovolemic hypotonic hyponatremia

A

Dehydration; decreased skin tugor, orthostatic hypotension, tachycardia, dry mucous membranes

37
Q

Clinical presentation of isovolemic hypotonic hyponatremia

A

Malaise, psychosis, seizures, coma

38
Q

Clinical presentation of hypervolemic hypotonic hyponatremia

A

Fluid overload; edema and weight gain

39
Q

Clinical presentation of acute hyponatremia

A

Nausea, malaise, weakness, headache, disoriented, coma, seizures, respiratory arrest

40
Q

Goal of hypovolemic hypotonic hyponatremia treatment

A

Restore the volume deficit

41
Q

Goal of isovolemic hypotonic hyponatremia treatment

A

Treat the underlying cause

42
Q

Goal of hypervolemic hypotonic hyponatremia treatment

A

Treat the underlying cause

43
Q

When treating Hypotonic hyponatremia the goal is to avoid rise in serum sodium >____mEq/L/hr or NMT ____ mEq/L/day

A

0.5 and 8-12

44
Q

Calculated Na+ deficit calculation

A

TBW * (Na normal-current Na serum)

45
Q

Rule of 8s

A

1/2 the sodium deficit should be replaced over 8 hours, 1/4 over the next 8 hours, and the last 1/4 over the next 8 hours

46
Q

Rapid infusions of 3% NaCl at 1-2 mL/kg/hr over 2/3 hours should only be done in patients with

A

Coma or seizures

47
Q

Total body water calculation for males

A

0.6 * wt (in kg) = ___L

48
Q

Total body water calculation for females

A

0.5 * wt (in kg)=___L

49
Q

In 1 L of 0.9% NaCl there are _____ mEq of Sodium

A

154

50
Q

In 1 L of 3% NaCl there are ____ mEq of Sodium

A

513

51
Q

Symptoms of acute symptomatic hyponatremia

A

Altered mental status; seizures; metabolic encephalopathy can develop

52
Q

Metabolic encephalopathy involves what physiologic changes

A

Cerebral edema, increased intracranial pressure (ICP), irreversible and fatal

53
Q

Treatment of acute symptomatic hyponatremia

A

Increase serum Na by 1-2 mEq/L/hr until symptoms resolve

54
Q

Short term goal of treatment for acute symptomatic hyponatremia

A

Serum Na+ 120 mEq/L - does not need to be corrected to 135 if correction will be too fast

55
Q

Result of overly rapid Na+ correction

A

Diffuse demyelinating lesion (central pontine myelinolysis)

56
Q

Max increase of Na+ serum levels in 24 hours

A

8-12 mEq/L

57
Q

Vaptan examples

A

Conivaptan (IV) and Tolvaptan (PO)

58
Q

Conivaptan (IV) and Tolvaptan (PO) promote

A

Excretion of free H2O

59
Q

Conivaptan (IV) and Tolvaptan (PO) are

A

Arginine vasopressin V2/V1A receptor antagonists

60
Q

When taking vaptans (conivaptan and tolvaptan) what occurs?

A
  • No loss in serum electrolytes
  • Increased urine output
  • Decreased urine osmolarity
  • Normalizes Na+ levels
61
Q

Conivaptan is used for _____ and ______ symptomatic hyponatremia

A

euvolemic and hypervolemic

62
Q

Tolvaptan is used for asymptomatic _____ and _____ hyponatremia

A

Euvolemic and hypervolemic

63
Q

Vaptan contraindicaitions

A
  • Hypovolemic hyponatremia
  • Patients without a sense of thirst
  • Anuria
  • Use with strong CYP3A4 inhibitors
64
Q

Acute symptomatic hyponatremia patients should be monitored _____

A

closely

65
Q

Patients with acute symptomatic hyponatremia should have serial exam of heart, lungs, and neurologic status _____ times over the first ______ hours

A

several; 12

66
Q

The serum Na+ concentration in acute symptomatic hyponatremia patients should be checked every ______ hours until they are asymptomatic

A

2-4 hours

67
Q

The serum Na+ concentration in acute asymptomatic hyponatremia patients should be checked every _____ hours until WNL

A

4-8 hours

68
Q

Hypernatremia is always associated with ______

A

hypertonicity

69
Q

______ occurs in patients with impaired thirst response or patients without access to water

A

Hypernatremia

70
Q

______ can be a result of loss of water/hypotonic fluids OR ingestion of sodium/hypertonic fluids

A

Hypernatremia

71
Q

With hypernatremia you must assess _______

A

volume status (ECF)

72
Q

Hypernatremia from hypertonic fluids is ____

A

uncommon

73
Q

How to restore hemodynamic status for hypovolemic hypernatremia patients

A

0.9% NaCl

74
Q

When restoring the free water deficit you should use _____

A

D5W

75
Q

_____ infusion does not affect electrolyte balance

A

D5W

76
Q

Do not correct the free H2O deficit too quickly. Give _____ total deficit over 24 hours and give ____ over the next 24-48 hours

A

1/2; 1/2

77
Q

While replacing the free H2O deficit the goal is _____ mEq/L/hr decrease with a max of ____ mEq/L/day

A

0.5; 12

78
Q

Isovolemic hypernatremia is found in patients that have _____

A

Diabetes insipidus

79
Q

Causes of isovolemic hypernatremia include

A

Central and nephrogenic causes

80
Q

Isovolemic hypernatremia treatment

A

Desmopressin (DDAVP) and Vasopressin

81
Q

Estimated change in sodium definition

A

Estimates the change (increase or decrease) in serum sodium per one liter of any given fluid

82
Q

Estimated change in sodium calculation

A

Change in Naserum = (Na fluid - Na serum)/(TBW + 1L)