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Have you ever wondered why sunlight exposure can make someone sneeze, aka 'photic sneezing'?

The photic sneeze reflex is a real thing, and reflects some cool neurophysiology. It also sports perhaps the greatest acronym in medical history.

Let's explore!

#tweetorial 2/
Perhaps the first to question why sunlight exposure can provoke sneezing was Aristotle.

In The Book of Problems (XXXIII, Problem 10), he asked, "Why is it that one sneezes more after one has looked at the Sun?"

loebclassics.com/view/aristotle…

cosmosmagazine.com/science/biolog….

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How could eating black licorice cause life-threatening hypokalemia?

Why in the world could specifically eating this food cause serum potassium levels to dangerously drop?

#medtwitter #tweetorial 2/
Let's first review what black licorice is actually made from.

Black licorice is a sweetener found in candy, tea, sweet drinks, and even beer.

It's extracted from the root of the legume Glycyrrhiza glabra plant.

licorice.com/blogs/news/wha…

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Why can multiple sclerosis symptoms worsen with heat exposure, something known as the Uhthoff phenomenon?

This question is especially relevant in the era of record-breaking heat waves and climate change.

#tweetorial #medtwitter 2/
In 1890, Wilhelm Uhthoff noted multiple sclerosis (MS) patients having a “marked deterioration of visual acuity during exercise" or after a hot bath, which ⬆️ body temperature.

1 patient lost vision just by walking vigorously in Uhthoff's clinic.

pubmed.ncbi.nlm.nih.gov/20375511/

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Has it ever occurred to you that Graves' disease presents a conundrum?

Graves' involves an autoimmune antibody that ACTIVATES a receptor, which is relatively unique in the landscape of human disease.

Let's unpack this fascinating mechanism.
#medtwitter #tweetorial 2/
Graves’ disease was first described by English physician Caleb Parry in 1786, when he noted an association between thyroid enlargement, tachyarrythmias, and exopthalmos in 8 patients.

Parry’s son posthumously published his description in 1825.

https://t.co/sklIBMwyzDlitfl.com/graves-disease/

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Ever wonder why amphotericin B can cause severe infusion reactions, including chills/rigors + hypotension?

These infusion reactions are so awful that it carries the nickname "amphoterrible".

Why does this happen? The answer is mind-blowing.

#medtwitter #tweetorial 2/
First let's review amphotericin B's history.

In 1953, analysis of a fermentation broth from Venezuelan soil found 2 antifungal compounds: amphotericin A and B.

B had a broader antifungal activity spectrum and so underwent further drug development.

pubmed.ncbi.nlm.nih.gov/33261213/

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Ever wonder why fluoroquinolones increase the risk of tendon rupture?

It seems so random that a whole class of antibiotics could cause tendon injuries, but the risk is real.

#medtwitter #tweetorial 2/
Fluoroquinolones inhibit bacterial function by blocking topoisomerase activity.

They first emerged as an antibiotic class in the 1960s, as byproducts of antimalarial quinine development.

Nalidixic acid = the first quinolone discovered.

pubmed.ncbi.nlm.nih.gov/14056431/

A short 🧵 on my 3️⃣-prong approach to rounding with resident teams in the MICU…

I emphasize 3️⃣ themes to the residents and fellows:

1️⃣ Clinical care
2️⃣ Education
3️⃣ Development

#MedTwitter #MedEd 1️⃣ Clinical care

I ask teams to focus on efficiency, ⬆️ time for teaching/ discussion

⏳⬇️ transitions b/w patients by alerting next RN
⏳Enter orders on rounds, w/ clearly defined roles as to who will do that
⏳Present from memory (if possible), focusing on critical issues

This is a thread of all of my tweetorials, in one place!

#MedTwitter

https://twitter.com/AvrahamCooperMD/status/1135370806798761987?s=20&t=JQN3cD53LMKOxjuQUsjpGQ

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How does the immune system achieve "self-tolerance", knowing not to attack and destroy the body's own tissues, like it does invading microbes?

This story involves scientific skepticism, T cell self-destruct signals, the thymus, and much more.

#tweetorial #medtwitter 2/
Quick disclaimer: this is an extraordinarily complicated topic that I've done my best to distill into essential elements.

The focus will be on the adaptive immune system more than innate.

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Why is the liver able to regenerate itself?

Somehow the liver has the incredible capacity to both heal itself after toxic injury and regrow after resection. No other solid organ in the body can regenerate like this.

#medtwitter #tweetorial 2/
It's assumed that the ancient Greeks knew of the liver's unique regenerative capacity, based on the myth of Prometheus (his liver regrew daily after an eagle ate it).

At the same time, scholars have found no other ancient evidence of this knowledge.

pubmed.ncbi.nlm.nih.gov/20472318/

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Have you ever wondered why Pseudomonas aeruginosa smells like grapes 🍇?

The answer relates to the ability of Pseudomonas to cause chronic airway infections and also coincidentally explains certain spoiled wine flavors.

#medtwitter #tweetorial 2/
Pseudomonas was first isolated in 1882 by the French pharmacist Carle Gessard, after he cultured it from the blue-green pus on bandages of injured soldiers.

academic.oup.com/cid/article/6/…

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Why would adenosine, a purine nucleoside, be able to treat supraventricular tachycardias (SVT)?

And why are its effects so short lived (e.g. <2 seconds)?

The answers will change the way you think about this drug.

#tweetorial #medtwitter 2/
Adenosine is an endogenous purine nucleoside that gets incorporated into RNA, ATP, and cAMP.

It has pleomorphic effects as a signaling molecule via A1, A2A, A2B, and A3 receptors.

pubmed.ncbi.nlm.nih.gov/25687993/

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Why is a ketogenic diet a potentially effective treatment for refractory epilepsy?

There's something almost magical about the idea that a specific type of diet could reduce the risk of epileptic seizures.

Let's explore why that might be.

#medtwitter #tweetorial 2/
First let's define a ketogenic diet.

Ketogenic diets have ⬆️ fat and ⬇️ carbohydrates. This leads to ⬆️ serum free fatty acids and ketone body production by the liver (acetoacetate, acetone, beta-hydroxybutyrate) for use as cellular fuel.

pubmed.ncbi.nlm.nih.gov/17241207/

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Ever wonder why tick bites can lead to a red meat allergy, including even anaphylaxis?

The answer requires us to examine sugars, tick saliva, and an anti-cancer drug.

#medtwitter #tweetorial 2/
The first inclination that a link b/w tick bites and meat allergy might exist occurred in Georgia in 1991.

10 cases were reported (but not published) of people developing hives or anaphylaxis w/ red meat ingestion, weeks to months after tick bites.

pubmed.ncbi.nlm.nih.gov/25747720/

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Clostridioides difficile (C. Diff) colitis is exceedingly rare in infants, almost as if they're protected from it.

But why would infants somehow be resistant to C. diff infection?

#medtwitter #tweetorial 2/
C.Diff was first isolated from 4 healthy newborn babies in 1935 by Hall and O'Toole.

💡The babies were all asymptomatic, but inoculation of this newfound bacteria in animals caused severe colitis.

They called this new strain Bacillus Difficilis.

jamanetwork.com/journals/jamap…

1/🧵
Ever wonder why rheumatic heart disease almost always damages heart valves?

And why is the mitral valve by far the most commonly affected?

The answer involves a case of mistaken identity.

#medtwitter #tweetorial 2/
The association between "rheumatism" and heart disease was first noted in the the late 1700s.

By 1832, the British physician James Hope observed that rheumatic heart disease (RHD) patients had valvular involvement, w/ loud cardiac murmurs on exam.

dp.la/item/29f298168…

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Ever wonder why corticosteroids like dexamethasone treat cerebral edema related to brain tumors?

I assumed the answer involved "anti-inflammatory effects", but there's much more going on.

#medtwitter #tweetorial 2/
The anti-edema effects of corticosteroids were first noted in 1955, when neurosurgeons gave cortisone perioperatively prior to craniopharyngioma resection.

⚡️The authors observed improved postoperative outcomes in the patients who received cortisone.

pubmed.ncbi.nlm.nih.gov/13272046/

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Third year of medical school, I was examining a patient in the ICU before rounds. In full PPE. Asking them how they felt that morning. Trying to absorb data to present later that morning.

Suddenly I heard my name overhead paged to the front of the unit. 2/
I assumed the team needed me to help with something patient-care related.

So I apologized to the patient, ungowned, and walked out of the room.

1/🧵

Why does chronic alcohol use cause macrocytosis?

Alcohol's ability to enlarge red blood cells (RBCs) has puzzled me ever since I learned about this association, but assumed it somehow poisons the bone marrow.

The answer is not so simple.

#medtwitter #tweetorial 2/
Clinicians in the 1930s first observed that patients with alcohol-related liver disease had RBC macrocytosis (defined currently as a mean corpuscular volume > 96 fL).

jamanetwork.com/journals/jamai…

1/🧵
Ever wonder why cutting onions makes you cry?

Something must be released that causes this irritating response, but what?

It turns out that cutting an onion jumpstarts multiple chemical reactions, in the air and right in front of your eyes.

#medtwitter #tweetorial 🧅 2/
💡Onions are actually one of the oldest cultivated crops, first entering the human diet ~5,000-7,000 years ago.

Ancient Egyptians worshipped onions (evoked eternity) and ancient Indians, Greeks, and Romans believed that they had medicinal properties.

onions-usa.org/all-about-onio…

1/🧵
Did you know that heparin can cause hyperkalemia?

But why would an anticoagulant like heparin increase serum K⁺ levels?

The answer also has a wild implication - that heparin may itself have a diuretic effect...

#medtwitter #tweetorial 2/
The first report of heparin-associated hyperkalemia occurred in 1964.

A patient had extended heparin exposure and developed progressive hyperkalemia (peak K⁺ level was 6.4 mEq/L), without another explanation.

pubmed.ncbi.nlm.nih.gov/14142415/