Hmm… he’s tasty, but he just needs a little salt
In this podcast, I discuss the management of hyponatremia in the ED. After reading countless articles from the nephrology literature…I can still attest that I have not a friggin’ clue about renal physiology. But I think I have found a simpler path to the work-up and treatment of low sodium in the ED.
When they are <130 is when I get a little worried
Step I-Send Lots of Labs
Here is what you need:
Serum-electrolytes, LFTs, osmolality, uric acid (if on diuretics), and you might as well send a TSH and cortisol as well (if you have any suspicion of an endocrine cause)
Urine-UA, urine lytes, urine urea, urine uric acid (if on diuretics), urine osm, urine creatinine
Want to learn more about FENa and FEUrea? Well I have an article for you.
Step II-Treat CNS dysfunction
If the patient is altered, comatose, seizing, or has neurologic findings, then raise the sodium by a little bit
Give 3% saline, 100 ml over 10-60 minutes (2 cc/kg up to a max of 100 cc)
10 minutes later, may repeat X 1
may be given peripherally through any reasonable IV
each 100 ml will raise sodium by ~2 mmol/l
Step III-Hang tight
Do not feel the need to do anything else, just fluid restrict the patient
Place a foley
Do not feel tempted to give NS
Do not be clever, just fluid restrict and admit.
Patients are at a fall risk with hyponatremia
Get a CT scan if they are still a little wacky
Remember the rules of 6’s (from the Stern article below)
Be incredibly careful when correcting hypokalemia, potassium repletion will raise the Na
Step IV-What to do when you couldn’t follow step III
dDAVP 1-2 mcg IV or SubQ x 1
Consider D5W 6ml/kg over 1 hour in consultation with renal if you have really screwed up
For more on this, see the Emergency Pharm D Blog
Drugs-Thiazides, SSRI, Sufonylureas, Opioids
1 liter of saline will allow a solute-low hyponatremia to make 6 L of urine
SIADH-need to get rid of a 600 mmol salt load/day. Can fluid restrict to 900 ml (400 insensible).
Read this excellent case report from Stern
Excellent Review by Schrier (Curr Opin Crit Care 2008;14:627)
Review of Drug-Induced Hyponatremia (Am J Kidney Dis 2008;52:144)
Understanding Lab Testing for Hyponatremia (Clin J Am Soc Nephrol 2008;3:1175)
The hyponatremia formulas do not work so well (Clin J Am Soc Nephrol 2007;2:1110 and Nephrol Dial Transplant 2006;21:1564)
Additional New Information
We have completely changed our strategy to most severe hyponatremia to utilize a dDAVP Clamp Strategy.
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