What Causes Low Sodium? Hyponatremia Workup (Lab Interpretation for New Nurse Practitioners)

What causes low sodium? It's common in primary care, and sodium is all about the kidney (& renal physiology can be 🙃🤯). But wait!

In this video, I'm breaking it down into simple, digestible steps to take for your workup and eval, so you don't have to melt your brain analyzing sodium channels.

In this video you'll get:

- How to know when your patients need to go to the ER, and when you can work them up outpatient for low sodium
- The simplest way to think about low sodium
- How to know if your patient needs IV fluid (or if that'd be the worst possible thing to do for them)

ERRATA: In the algorithm part 2, I said SIADH = high uric acid but actually it's LOW, so please excuse that error. And for volume overloaded states it tends to be higher (not low) (time stamp 21:25)

The patient's labs say a GFR of 32 with a creatinine of 0.8 - NOT correct - I said the GFR was normal (that's not, and it doesn't match!). Not sure what was going on that day of recording but I believe his Cr was accurate, which would make his GFR normal, over 60 (3:43)
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More Resources:

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Come follow along for even more tips and inspiration:

[lat]

These are really good! Please keep them coming!

[tseringwachungtsang]

Thank you, Liz for your wonderful videos. You are an awesome provider. You are compassionate and have a great passion to teach and share. I wish I could have you as my mentor.

[kentaro]

You're a great teacher. Thank you for your videos.

[TheShiro]

Thank you so much for posting this. It's very informative.

[lupullum]

Great informative video, made a lot of sense, Thank You

[nicolechen]

I'm not a brand new np but still find your vedioes very helpful. Thank you

[urgentcaredr]

I’ve been watching your videos for a few weeks and they are so helpful. You are humble and knowledgeable. Love how you break down concepts and
I love the case studies. I’m a NP student in my last year. Wish I had all your knowledge. Thank you!

[matthewpixley]

Two years ago my sodium dropped from 134 level for 3 years, to 102. I was admitted to ICU and stayed for 4 days. I’m now 132 and doing much better. I couldn’t walk for 1 week after getting released from the hospital. I had some neurological issues with speaking and balance for a year afterwards. Glad to be ok now.

[marybodenheimer]

I enjoyed this video on hyponatremia. Would you please share the calculation (or where to find it) which you adjusted sodium level with an elevated glucose level.

[vetoef]

GFR of 32ml/min normal? Um no. I think his eGFR is actually over 100ml/min with Scr of 0.8. So correct statements but slide is incorrect... GREAT VIDEO! Really difficult topic and explained VERY WELL! RBDNP

[alextalarico]

Hi Liz! Great lecture as always!
I apologize if I simply missed this... Based on your algorithm, what would the next step be (from a family practice NP perspective) once you discover that the urine osmol is high and that the cause is likely ADH-related? Is there further workup we should do in primary care or would you refer? And if referral is warranted, would that be under the umbrella of endocrinology or nephrology? Thank you as always for your awesome content!

[Sofiahansen_]

thank you for very informative video. what is the impact of SSRIs ?

[claytonrogers]

Do you have a resource for switching from one BP med to another in terms of equivalency?

Also I think I’ve asked if you have a method of triage when you’re deciding which lab abnormalities to tackle first?

[russellm]

I ended up in the ER recently because of low sodium levels. I guess I was drinking too much water.
I was drinking up to 2 gallons a day sometimes more.
My level was below 130. Could I just continue drinking the same amount of water and just take some salt throughout the day?
Or do the other electrolytes and other minerals/vitamins etc need replaced also.
They said to just cut down on the water to no more than 5 of the plastic hospital drinking mugs per day.
Great video.Thank you.

[shaleenas]

Hi! All of the references I’ve been reading (up to date and AAFP) mention that your acid levels are low and SIADH. However, you mention in your video that serum uric acid levels are high in SIADH. Can you clarify this?

[jegreen]

This was very useful information! i do have a question: I have always understood that drinking beer or alcohol would lead to dehydration, which could lead to hypernatremia, right? but in this case study, this man who is hardly drinking water and having a 6 pack of beer every day has hyponatremia. Can you help me think this through? could he actually have been in a state of hypernatremia if it weren't for the Chlorthalidone??

[gylygos]

Well recently, I got sick with cramping vomiting that lasted me almost 5 days I was in bad shape, but thank God I have gotten better and my doctor did my bloodwork and told me I had low sodium not sure if it’s from drinking too much water or not adding enough salt in my diet I wouldn’t eat a lot of salt because I try to watch my blood pressure but I didn’t know it could lead to this.

[benjaminlew]

Hi, Liz - I came across this insightful video after a search on hyponatremia. I have a question about when to go to the E.R. If someone receives a sodium value of less than 130 in an outpatient PCP setting, is it always required to go to the E.R. for a recheck (as you discuss at the 7-min:30-sec mark)? Would rechecking via non-E.R. means ever be appropriate (such as returning to the PCP)?

[bigsamtheevangelist]

Not sure if it's okay to ask here but just trying to figure out what's going on with me. Had abdominal pain and should pain which seemed like gallbladder problems but it wasn't and ultrasound checked out normal. Looking at my blood results my sodium is at134, Glucose 98 after fasting 8 hours, protein is at 8.0. Is this signs of Hyponatremia? also had diarrhea issues the day before. I do drink sweet tea a lot sometimes so not sure if thats anything?

[ChandraPalGupta]

Good lecture. Please try to be at slow speed.