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Reposted by Tony Breu

Tony Breu @tonybreu.bsky.social · Nov 28

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🤔 Why doesn't an elevated BUN lead to extreme thirst? If increased serum osmolarity compels us to seek water, uremia should be a significant driver of this craving.

And yet, it isn't.

Let's examine why.

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Reposted by Tony Breu

Ryan Feldman PharmD DABAT @empoisonpharmd.bsky.social · Nov 28

If Tony breu is here we are in the right place

Tony Breu @tonybreu.bsky.social · Nov 28

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🤔 Why doesn't an elevated BUN lead to extreme thirst? If increased serum osmolarity compels us to seek water, uremia should be a significant driver of this craving.

And yet, it isn't.

Let's examine why.

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Reposted by Tony Breu

Elliot Tapper @ebtapper.bsky.social · Nov 27

Portal hypertension and the development of varices

If only there was a way to block the alpha and beta adrenergic pathways to offset these changes

IF ONLY!!!!

#medsky #liversky

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Reposted by Tony Breu

David S. Goldfarb MD @weddellite.bsky.social · Nov 28

Glucose IS an effective osmole in the absence of insulin or insulin resistance. So hyperglycemia does lead to polydipsia (and polyuria due to osmotic diuresis)

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Reposted by Tony Breu

Tony Breu @tonybreu.bsky.social · Nov 17

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Does the tryptophan in turkey really cause a food coma?

I've heard this repeatedly, while also being told that it is a myth. Let's have a look at the physiology of a Thanksgiving meal...

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Tony Breu @tonybreu.bsky.social · Nov 28

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💧 An increase in effective osmoles (e.g., sodium) produces thirst via the movement of water out of cells (i.e., intracellular dehydration)
💧Urea and other ineffective osmoles don't produce the same shifts and, therefore, lead to less thirst

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Tony Breu @tonybreu.bsky.social · Nov 28

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The mechanism described above helps explain why other ineffective osmoles that increase serum osmolarity (e.g., glucose) are not independent drivers of thirst.

t.ly/odecD

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Tony Breu @tonybreu.bsky.social · Nov 28

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The explanation above leads to a beautiful symmetry of thirst promoters.

Either...

➤EXTRAcellular volume depletion

...or...

➤INTRAcellular volume depletion...

...will make you seek water.

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Tony Breu @tonybreu.bsky.social · Nov 28

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What is the "sensor" for cellular dehydration?

It appears that transient receptor potential vanilloid 1 (TRPV1) is key. TRPV1 is a non-selective cation channel that detects harmful stimuli like heat and capsaicin.

💡 It is also activated by cell shrinking!

t.ly/lqhvy

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Tony Breu @tonybreu.bsky.social · Nov 28

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Based on this experiment, Gilman concluded that it is INTRAcellular dehydration that leads to thirst.

This results from a hypertonic extracellular space (e.g., hypernatremia) and the movement of water outside of cells.

t.ly/It2oB

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Tony Breu @tonybreu.bsky.social · Nov 28

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Gilman then made another crucial observation:

💡Only NaCl led to a reduction in serum specific gravity. This suggested a shift of water from the intracellular to the extracellular space.

This only occurs with an effective osmole (e.g., sodium) and not an ineffective osmole (e.g., urea).

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Tony Breu @tonybreu.bsky.social · Nov 28

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After 30 minutes, the dogs were offered water, and had blood work drawn. Gilman made two key observations:

🔑 The increase in serum osmolarity with hypertonic NaCl and urea were nearly identical
🔑 Dogs drank significantly more water after hypertonic NaCl injection

t.ly/MIdqH

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Tony Breu @tonybreu.bsky.social · Nov 28

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We've known for nearly a century that an increase in serum urea is not a significant driver of thirst.

In 1937, Alfred Gilman published an experiment in which dogs received an IV injection of either:
➤20% NaCl
➤40% urea

Both are hypertonic solutions.

t.ly/MIdqH

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Tony Breu @tonybreu.bsky.social · Nov 28

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🤔 Why doesn't an elevated BUN lead to extreme thirst? If increased serum osmolarity compels us to seek water, uremia should be a significant driver of this craving.

And yet, it isn't.

Let's examine why.

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Tony Breu @tonybreu.bsky.social · Nov 23

Already done!

bsky.app/profile/tony...

Tony Breu @tonybreu.bsky.social · Nov 18

I used @en.blueark.app to transfer tweetorials previously posted on Twitter here to @bsky.app. Very fair price and quick process.

If you do the same, note my previous comments, particularly regarding links and search.

Tony Breu @tonybreu.bsky.social · Nov 17

A few observations on BlueSky, after a week of use:

☞REPOSTS v LIKES: I don't see what others like, so reposts seem more powerful
☞LINKS: These consume the number of characters in the link, not a set amount (like Twitter)
☞SEARCH: I'm underwhelmed. It doesn't consistently result posts I know exist

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Tony Breu @tonybreu.bsky.social · Nov 22

I agree. Similarly, "tweetorial" can be applied to any set of threaded posts, no matter the site.

It's not too dissimilar to a Band-Aid. My kids call all adhesive bandages Band-Aids, even those not made by J&J.

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Tony Breu @tonybreu.bsky.social · Nov 22

It's already here!

What's cool is that it's got the original date I posted it too! This is thanks to @en.blueark.app

bsky.app/profile/tony...

Tony Breu @tonybreu.bsky.social · Sep 9

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Why does acute pulmonary embolism (PE) cause hypoxia?

It took me a while to realize I didn't have a good answer. Think about it: the blood upstream of the clot should be fully oxygenated. Where is the blood that isn't being oxygenated?

The answer is pretty cool...

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Reposted by Tony Breu

Rahul Ganatra @rbganatra.bsky.social · Nov 22

Sigh. Only about half of veterans with cirrhosis hospitalized with SBP received guideline-directed IV albumin:

journals.lww.com/ajg/abstract...

Rates increased from 2008 to 2022, but disparities persistent: black patients were less likely to get albumin than white patients.

Lots of work to do.

Albumin for Spontaneous Bacterial Peritonitis: Care... : Official journal of the American College of Gastroenterology | ACG

ated trends and patient, practice-, and facility-level factors associated with use among patients with cirrhosis hospitalized for SBP confirmed with ascitic fluid criteria. Results: Among 3,871 Vet...

journals.lww.com

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Tony Breu @tonybreu.bsky.social · Nov 21

I did the same.

Not expensive and provides me a way to reference "old work." The only issue has been splitting tweets into two posts when I have a long URL (BlueSky doesn't have a set character allocation for links).

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Reposted by Tony Breu

Christopher Chiu, MD @cjchiu.bsky.social · Nov 21

I'm in favor of still calling them #tweetorials as well. It feels delightfully anachronistic and points to the roots/history on the other platform. #MedSky, who is with me?

Tony Breu @tonybreu.bsky.social · Nov 17

I agree, Liz.

I favor continuing to call them tweetorials or using something that applies to all platforms (e.g., MedThread or EdThread).

Using something unique to each platform makes less sense to me. If I post a GIF or video, it's called a GIF or video, regardless of the site.

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Tony Breu @tonybreu.bsky.social · Nov 20

There appears to be some association (pubmed.ncbi.nlm.nih.gov/25270263/) though in a phase 2 trial the primary end point was not met (pubmed.ncbi.nlm.nih.gov/33754202/).

It seems like an RCT is complete though no results reported (clinicaltrials.gov/study/NCT050...)

Interleukin-31 is associated with uremic pruritus in patients receiving hemodialysis - PubMed

IL-31 may play an important role in the pathophysiology of uremic pruritus.

pubmed.ncbi.nlm.nih.gov

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Reposted by Tony Breu

Joel Topf @kidneyboy.bsky.social · Nov 19

Honey, stop what you're doing, new hyponatremia research just dropped!

What's it say?

It looks like slow correction is associated with worse outcomes, like death and length of stay!

Was it just a small study?

No, it was a meta-analysis of almost 12,000 patients!

jamanetwork.com/journals/jam...

Correction Rates and Clinical Outcomes in Hospitalized Adults With Severe Hyponatremia

This systematic review and meta-analysis evaluates the association of sodium correction rates with mortality among hospitalized adults with severe hyponatremia.

jamanetwork.com

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Tony Breu @tonybreu.bsky.social · Nov 19

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It will be interesting to see if nemolizumab, an interleukin-31 receptor alpha antagonist, helps mitigate lymphoma-associated pruritus in the rare case when it becomes refractory.

This drug has been tested in atopic dermatitis with pruritus and was effective.

t.ly/-i6US

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Tony Breu @tonybreu.bsky.social · Nov 19

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The mechanism involves a cytokine unfamiliar to me: IL-31.

In one study of HL and angioimmunoblastic T-cell lymphoma, those with pruritis had higher serum levels of IL-31, IL-1β, and IL-1α than those with lymphoma and no pruritis compared with controls.

t.ly/KxLw9

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Tony Breu @tonybreu.bsky.social · Nov 19

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The association between HL (and other lymphomas) and pruritus has prompted many to recommend a chest x-ray as part of the initial work-up when a primary skin disorder isn't present.

A 2013 NEJM review suggests this, as does Up-To-Date.

t.ly/wB5Xv

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