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PHRM 844 > Lecture 2 - Electrolytes Hyponatremia > Flashcards

Lecture 2 - Electrolytes Hyponatremia Flashcards

1
Q

Na Range

A

135-145 mEq/L

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2
Q

Sodium (135-145 mEq/L)

  • primary ___ cation
  • needed to maintain cellular ___
  • maintains osmolar gradient which regulates fluid ___ throughout the diff compartments
A
  • extracellular
  • integrity
  • homeostasis
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3
Q

Hyponatremia

  • most ___ and complicated disturbace
  • too rapid correction of Na results in ___
  • ___ injury
  • acute effects of hypo-osmolarity
  • significant morbidity and mortality
A
  • common
  • demyelination
  • brain
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4
Q

Na level less than ___ is considered hyponatremia

A

Na < 135 mEq/L

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5
Q

Osmolality (275-290 mOsm/L)

  • number of ___ per L of water
A

particles

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6
Q

serum Osm calculation should predict the measured serum osm within ___ mOsm/L

A

5-10 mOsm/L

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7
Q

Example Serum Osm Calculation

Osm = (2 x Na) + (BUN/2.8) + (glucose/18)

Actual serum Osm = 322 mOsm/L

A

Osm = (2 x 145) + (10/2.8) + (90/18)
= 299 mOsm/L

since actual serum Osm is greater than 5-10 mOsm/L from what was calculated, we know theres some other substance in the blood

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8
Q

Pseudohyponatremia (Isotonic)

  • extreme elevations of lipid and proteins increase the total plasma volume
  • can be seen with ___ or ___
  • leads to a dilution effect
  • sodium appears low (it is still there, just ___ )
  • ___ serum osmolality is not significantly affected
  • ___ Osm is low (due to low sodium)
  • Leads to an osmolality gap (OG)
A
  • hypertriglyceridemia, hyperproteinemia
  • displaced
  • measured
  • calculated

Calculated is low but measued isn’t affected

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9
Q

Hypertonic Hyponatremia

Na is low, what is making this hypertonic?

What is the calc Osm?

A

glucose is 6x normal level

(2 x 128) + (50/2.8) + (600/18) = 307 mOsm/L

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10
Q

Hypertonic Hyponatremia - Corrected Serum Na

What is the corrected Na?

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

A

128 + 1.6[(600-100)/100] = 136 mEq/L

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11
Q

Hypotonic Hyponatremia

  • > ___ of all hyponatremia
  • most important step is to clincally assess the pt’s ___ volume
  • hypovolemic, isovolemic, hypervolemic
A
  • 90%
  • ECF
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12
Q

often the sickest patients are ___ volemic, ___ tonic, ___ natremic

A

hypo, hypo, hypo

need fluid and Na

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13
Q

Hypovolemic Hypotonic Hyponatremic

decrease in both ___ and ___
___ causes (urine Na > 20 mEq/L)
- ___ /excessive diuresis
- adrenal insufficiency ( ___ deficiency)
- salt losing nephropathy
- ___ salt wasting

A

total body water and Na
renal
- diuretics
- mineralcorticoid
- cerebral

pt is typically on diuretic
hormonal or CNS disorder

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14
Q

Hypovolemic Hypotonic Hyponatremic

T or F: if urine Na is low (urine Na < 20 mEq/L), it’s a renal cause

A

F; non-renal

if you are peeing out a lot of Na it’s renal

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15
Q

Hypovolemic Hypotonic Hyponatremic

___ causes (urine Na < 20 mEq)
- blood loss/hemorrhage
- skin losses (burns, sweat, wounds)
- GI losses (vomiting, diarrhea, suction)

A

non-renal

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16
Q

Isovolemic Hypotonic Hyponatremia

raised TBW and normal/slightly raised total body ___
- slight excess of ___ fluid
- no edema
- clinically appears ___
causes
- adrenal insufficiency (___ deficiency)
- ___thyroidism
- psychogenic polydipsia
- SIADH ( ___ )

A

Na
- ECF
- euvolemic
- glucocorticoid
- hypothyroidism
- syndrome of inappropriate antidiuretic hormone release

17
Q

SIADH

most common cause of isovolemic hypotonic hyponatremia
- water intake ___ capacity of kidneys to excrete water
- urine Osm generally > ___ mOsm/kg
- urine Na generally > ___ mEq/L
- causes: tumors, CNS disorders, ___

syndrome of inappropriate antidiuretic hormone release

A
  • exceeds
  • 100
  • 20-30
  • drugs
18
Q

Possible Drug-induced SIADH

A
  • antipsychotics
  • carbamazepine
  • SSRIs (fluoxetine and sertraline)
19
Q

Treatment of SIADH

  • remove underlying cause (most likely ___ )
  • First line: ___ restriction
  • __ may be benefcial if 24-48 hours of free water restriction fails (“___”)
  • 2 examples:
A
  • medications
  • free water
  • Vaptans, “aquaretics”
  • Conivaptan and Tolvaptan
20
Q

Hypervolemic Hypotonic Hyponatremia

  • total body ___ is increased but ___ is increased even MORE
  • expanded ___ fluid volume and ___
  • seen with: cirrhosis, heart failure, kidney failure, nephrotic syndromes
A
  • Na, TBW
  • ECF, edema
21
Q

clinical prsentation of hypotonic hyponatremia

mostly asymptomatic (Na > ___ mEq/L)
hypovolemic = ___
- decreased skin turgor, orthostatic hypotension, tachycardia, dry mucous membranes

isovolemic
- malaise, psychosos, seizures, coma

hypervolemic
- ___ and weight gain

acute hyponatremia
- nausea, malaise, weakness, headache, disorented, coma, seizures, respiratory arrest

A
  • 125
  • dehydration
  • edema
22
Q

Goals of Treatment

Hypovolemic
What do we want to do?

A

restore volume deficit

23
Q

Goals of Treatment

Isovolemic or Hypervolemic
What do we want to do?

A
  • determine underlying cause
  • is pt symptomatic?

dont want to add more volume if we dont have to (will mak worse)

24
Q

Goals of Treatment

in most cases the goal is to avoid rise in serum sodium > ___ mEq/L/hr or no more that ___ mEq/L/day

A
  • 0.5
  • 8-12
25
Q

Treatment options

Hypovolemic
- ___ NaCl ( ___% NaCl) if symptomatic
- ___ NaCl ( ___NaCl) if asymptomatic

A
  • hypertonic, 3%
  • isotonic, 0.9%
26
Q

Treatment options

Isovolemic
- ___ and ___ % NaCl if symptomatic
- ___ NaCl and ___ restriction if asymptomatic

A
  • furosemide, 3%
  • 0.9%, water
27
Q

Treatment options

Hypervolemic
- ___ and judicious ___ NaCl if symptomatic
- ___ in asymptomatic pts

A
  • furosemide, 3%
  • furosemide
28
Q

acute vs chronic hyponatriemia

Acute
- brain swells with ___
- ___ edema
- ___ neurologic Sx
- brain herniation
- death

A
  • water
  • brain
  • severe
29
Q

acute vs chronic hyponatriemia

Chronic
- brain cells extrude ___
- minimal brain ___
- ___ neurologic Sx
- brain herniation rare
- death is rare

A
  • solutes
  • swelling
  • mild
30
Q

acute symptomatic hyponatremia

Sx typically ___ related
- altered mental status
- seizures

Metabolic encephalopathy can develop
- cerebral ___
- increased intracranial pressure (ICP)
- irreversible and sometimes fatal

A
  • CNS
  • edema

prompt treatment needed

31
Q

acute hyponatremia treatment

increase serum Na by ___ mEq/L/hr until symptoms resolve
- reasonable short term Na goal ___ mEq/L
- complete corretion is ___
- if corrected too rapidly, diffuse ___ lesions (CPM). Irreversibe.
- generally, an increase of ___ mEq/L is sufficient to reverse most acute manifestations
- MAX increase of ___ mEq/L in the first 24 hrs

A

1-2
* 120
* unecessary
* demyelinating
* 4-6
* 8-12

CPM = central pontine myelinolysis

32
Q

T or F: risk of cerebral edema from hyponatremia far outweighs risk of demyelination from correcting too rapidly?

A

T

lesser of 2 evils

33
Q

known demyelination risk factors:
- serum Na < ___ mEq/L
- ___kalemia
- alcohol use disorder
- malnutrition
- advanced ___ disease

potential risk factors:
- hypoxemia
- cancer
- severe burns
- diabetes
- renal faillure
- increase in Na exceeeding ___ mEq/L in 48 hrs

A
  • 105
  • hypo
  • liver
  • 25
34
Q

Rule of 8s

replace half of Na deficit in 8 hrs, then remaining deficit within ___ hrs

A

8-16

35
Q

know how to calculate Na replacement

A

slides 95-98

36
Q

acute symptomatic hyponatremia monitoring

  • heart, lungs, and neurologic status should be checked several times over first 12 hours
  • check serum Na concentrations q ___ hrs until asymptomatic
  • then check serum Na q ___ hrs until WNL
A
  • 2-4
  • 6-8
37
Q

Vaptans

Conivaptan (IV) and Tolvaptan (PO)
- arginine vasopressin V2/V1A receptor ___
- promotes excretion of free ___
- no loss in serum ___
- normalized ___ levels
- $$$

A
  • antagonist
  • H2O
  • electrolytes
  • Na

basically a diuretic that doesnt drain electrolytes

PHRM 844 (52 decks)

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