Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
29 Cards in this Set
- Front
- Back
|
Normal osmolality:
|
275 - 290 mOsmol/kg
|
|
|
What osmolality makes us thirsty
|
295 mOsmol/kg
|
|
|
Hyponatremia defined
|
Na < 136
|
|
|
Work up for Hyponatremia
|
Initial chemistry panel
Plasma and urine osmolality (+/- urinanalysis) Spot urine sodium concentration |
|
|
Symptoms of Hyponatremia
|
Brain cells swell, cerebral edema
Asymptomatic Nausea, headache Malaise, lethargy, confusion If below 120: Seizure risk increases, coma |
|
|
Discuss the "measured osmolality" in Hyponatremia
|
Most commonly, osmolality will be HIGH
|
|
|
What's the formula for "calculated osmolality"?
|
2(Na + K) + BUN/2.8 + Glucose/18
|
|
|
If "calculated osmolality" differs from "measured osmolality" by more than 10, another osmotically active solute is present like what
|
Lipids, proteins, mannitol, glycine, etc.
|
|
|
TEST QUESTION
Most common cause of Hyponatremia, high osmolality: |
Hyperglycemia
|
|
|
For every 100mg/dl of glucose above normal, Sodium decreases ____ mg/dl
|
1.6
i.e. Glucose 500 (80 -100), Sodium 133.6 (136-145) |
|
|
Other causes of Hyponatremia, high osmolality
|
Ethanol, Mannitol, Methanol
|
|
|
In Hyponatremia, low osmolality, the appropriate renal response is urine with Specific gravity 1.003 and
Urine osmolality <100 mOsmol/kg So what's the problem? |
the kidney's aren't working properly, and will not have the appropriate response
|
|
|
Hyponatremia, normal osmolality:
Discuss lipid and protein blood profile |
Hyperlipidemia
Hyperproteinemia (above 10) |
|
|
Hyponatremia, normal osmolality:
Differs from Hyponatremia, high osmolality by ______ |
slower onset, sodium “reset” to maintain osmolality in normal range.
|
|
|
TEST QUESTION
2 most important Causes of Hyponatremia |
Hyperglycemia
Syndrome of inappropriate AVP secretion |
|
|
TEST QUESTION
medications causing hyponatremia |
Selective Serotonin Reuptake Inhibitors (SSRI)
|
|
|
TEST QUESTION
Name some SSRIs |
Fluoxetine (Prozac)****
Sertraline (Zoloft)**** Paroxetine (Paxil) Citalopram (Celexa) |
|
|
TEST QUESTION
What group of people in what situation is the most affected by SSRI caused hyponatremia |
Particularly in females
Particularly post-operatively |
|
|
TEST QUESTION
Treatment of Hyponatremia |
Correct underlying cause
i.e. lowering blood glucose will correct sodium If 120 or above, or if chronic – treat conservatively If below 120, or decompensated – treat aggressively with 3% NaCl If fluid overloaded, restrict H20 (1.5 l/day), sodium (2gm/day), and diurese with loop H20 > Na+ loss in urine If euvolumic, restrict H20 and sodium If dehydrated, give I.V. fluids (0.9% or 3% NaCl) |
|
|
TEST QUESTION
If Na level is below 120, or decompensated – treat how? |
aggressively with 3% NaCl
|
|
|
TEST QUESTION
If you treat hyponatremia too rapidly, what happens? |
Central Pontine Myelinolysis (CPM)
|
|
|
Central Pontine Myelinolysis (CPM)
AKA? |
Osmotic Demyelination Syndrome (ODS)
|
|
|
TEST QUESTION
Maximum rate of correction of hyponatremia |
Maximum correction:
1.5 mEq/l per hour for first 3-4 hours, 12 mEq/l over first 24 hours. |
|
|
what happens in CPM?
|
rapidly evolving quadriplegia and pseudobulbar palsy
flaccid paralysis of all four limbs and an inability to chew, swallow, or speak the presence of CPM is frequently obscured by coma from a metabolic or other associated disease |
|
|
Goal of Na+ Correction
|
Raise Na to 120, limit to12mEq over 24*
|
|
|
How do you estimate total bdy water weight?
|
0.5 * body weight
|
|
|
Formula for sodium deficit
|
(Goal Na - Actual Na) * half of body weight
i.e. (120 – 110) x 0.5 x 70 = 350 mEq |
|
|
1 liter Normal saline (0.9% NaCl) = ____ mEq
|
154
|
|
|
IMPORTANT
The speed limit for correction is 12mEq/L of Na per 24 hrs. This equates a limit of how much Na correction for a 70kg dude? |
420 mEq
i.e. (120 – 108) x 0.5 x 70 = 350 mEq |
