Samantha Wang Profile picture
Sep 24, 2020 16 tweets 7 min read Read on X
1/15 #MedTwitter: You're admitting a 64YO male with ESRD on HD for hyperkalemia after missing dialysis. A troponin was checked & returned at 0.78 (nl<0.055 ng/mL), similar to his baseline. He is w/osymptoms and EKG is w/o dynamic changes. What would you call this #tropbump?
2/15 Have you ever been taught to think about troponin as being cardiac vs. non-cardiac in origin? Though this may be a nice framework, it’s simply untrue: if you’re measuring cardiac troponin I (cTnI), it is expressed only on myocardium(not skeletal muscle, unlike troponin T).
3/15 The lexicon to describe troponins is confusing!

"𝘛𝘳𝘰𝘱𝘰𝘯𝘪𝘯𝘦𝘮𝘪𝘢" is frequently used but is not very helpful. It is NOT a diagnosis or etiology, and should probably be abandoned as a term altogether.
4/15 Here’s a framework for thinking about #tropbumps.

Ask: are there signs of ischemia? If so, you may be facing an “𝗠𝗜”: 𝘮𝘺𝘰𝘤𝘢𝘳𝘥𝘪𝘢𝘭 𝘪𝘯𝘧𝘢𝘳𝘤𝘵𝘪𝘰𝘯, which can be due to plaque rupture/thrombus (Type 1) or myocardial oxygen demand/supply mismatch (Type 2).
5/15 With type 2 MIs, classically, 𝗹𝗼𝗼𝗸 𝗳𝗼𝗿 𝘃𝗶𝘁𝗮𝗹 𝘀𝗶𝗴𝗻 𝗱𝗶𝘀𝘁𝘂𝗿𝗯𝗮𝗻𝗰𝗲𝘀.

Type 2 MIs can occur in the presence of fixed atherosclerosis, but coronary artherothrombosis is not the underlying cause for troponin elevation.
6/15 And then there’s 𝗠𝗜𝗡𝗢𝗖𝗔.

𝘞𝘩𝘢𝘵 𝘵𝘩𝘦 𝘩𝘦𝘤𝘬 𝘪𝘴 𝘔𝘐𝘕𝘖𝘊𝘈?
7/15 𝘔𝘺𝘰𝘤𝘢𝘳𝘥𝘪𝘢𝘭 𝘪𝘯𝘧𝘢𝘳𝘤𝘵𝘪𝘰𝘯 𝘸𝘪𝘵𝘩 𝘯𝘰 𝘰𝘣𝘴𝘵𝘳𝘶𝘤𝘵𝘪𝘷𝘦 𝘤𝘰𝘳𝘰𝘯𝘢𝘳𝘺 𝘢𝘵𝘩𝘦𝘳𝘰𝘴𝘤𝘭𝘦𝘳𝘰𝘴𝘪𝘴 = MINOCA, and accounts for 6% of MIs. It is much more common in women than men.
8/15 Mechanisms of MINOCA vary, but patients typically present with symptoms of acute MI – which can even include a STEMI! – but are found to have non-obstructive or no CAD and all other causes of myocardial injury are ruled out.
9/15 If your patient has no signs, symptoms, or findings of myocardial ischemia, you are dealing with 𝗺𝘆𝗼𝗰𝗮𝗿𝗱𝗶𝗮𝗹 𝗶𝗻𝗷𝘂𝗿𝘆 w/o ischemia, which comes in 2 flavors: acute or chronic depending on the serial troponin variability.
10/15 In the case of our patient, he most likely has 𝘤𝘩𝘳𝘰𝘯𝘪𝘤 𝘮𝘺𝘰𝘤𝘢𝘳𝘥𝘪𝘢𝘭 𝘪𝘯𝘫𝘶𝘳𝘺 without ischemia.

You may have learned that high troponins in ESRD is from decreased clearance. If that were true, troponins should change pre vs. post dialysis, right?
11/15 The data is mixed here. Some studies show no troponin change pre/post dialysis; others show slight decrease.

pubmed.ncbi.nlm.nih.gov/10085490/
12/15 ⬇️clearance alone doesn't explain the whole picture of asymptomatic troponin elevation in ESRD.

❤️Myocardial microinjury from osmolarity/ion fluxes, preload/afterload changes, calcium deposition are at play as well.
13/15 Ever wonder why patients with stroke can have high troponins? Is it cardioembolic? Or catecholamine mediated?

𝘛𝘙𝘌𝘓𝘈𝘚 found that patients with ischemic strokes were less likely to have obstructive CAD compared to matched NSTEMI patients.

pubmed.ncbi.nlm.nih.gov/26933082
14/15 The study hypothesized catecholamine-mediated ❤️ injury, but was small in size.

More recent studies have suggested possible cardioembolic etiologies (ie. MINOCA).

pubmed.ncbi.nlm.nih.gov/29167390
15/15

𝗧𝗮𝗸𝗲𝗮𝘄𝗮𝘆𝘀:
1.Abandon the term “troponinemia”.
2.Not all troponin elevations are “MI”s. The term MI should be reserved only for ischemic causes.
3.When there are no findings of ischemia, you are dealing with myocardial injury.

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More from @DrSamanthaWang

Aug 28, 2020
#MedTwitter: It is switch weekend/Friday! How do you like to sign-out your patient list to the oncoming physician?
I was once a proponent for the email sign out: putting words to paper (or screen) helped me organize my thoughts. And frankly, was more convenient.

But recently, I signed out to my colleague via phone and 💙 it!
We ended-up talking not only about the patients on our list, but past experiences on similar undifferentiated/challenging cases, and our emotional/psychological well-being during present times.

I now prefer signing out via 📞 and encourage you to try it as it:
Read 5 tweets
Aug 12, 2020
1/15: #MedTwitter: You are admitting a 50-year-old man with a hx GI bleed for a PE. You start a heparin drip. What do you titrate the drip to?
2/15: At my institution, heparin anti-Xa levels (HAL) are recommended, but we routinely draw both aPTT and HAL. I’ve always wondered WHY?

There’s also the page: “The aPTT is supra-therapeutic but the HAL is therapeutic, which should we use?”

Let’s de-mystify this!
3/15: First, let’s understand unfractionated heparin (UFH).

UFH is a negatively charged, heterogenous mix of oligosaccharides. Heparin MUST bind antithrombin (AT) to have an anticoagulant effect. AT then inhibits Xa, thrombin (II), and other proteases.

pubmed.ncbi.nlm.nih.gov/27384570/
Read 16 tweets
Aug 4, 2020
1/14 #MedTwitter: The ED pages you for an admission: a 24-year-old male with a history of IVDU presenting with fever. How do you take his drug history?
2/14 As a resident, I fell into A + B, until @cuttingforstone taught me you need to know a lot more to appropriately Dx and Tx your patient. My mnemonic?

𝗗𝗥𝗨𝗚: Drug, Route, User, Goods.
3/14 Buckle up for a deep dive into why a detailed drug history matters!
Read 15 tweets
Jun 22, 2020
1/9: A woman presents with diarrhea x 2 weeks that woke her from sleep. I love this fantastic framework for chronic diarrhea by @LindseyShipley8
2/9 We reviewed her admission EKG. What do you notice? Image
3/9 #MedTwitter: What’s your ddx for low EKG voltage? Think back to physiology. The space between EKG leads &❤️ can be filled with: 𝗳𝗹𝘂𝗶𝗱 (pleural/pericardial effusion), 𝗮𝗶𝗿 (PTX, COPD), 𝗳𝗮𝘁, 𝗶𝘀𝗰𝗵𝗲𝗺𝗶𝗮 (dead tissue) or 𝗶𝗻𝗳𝗶𝗹𝘁𝗿𝗮𝘁𝗶𝘃𝗲 processes.
Read 10 tweets
Jun 19, 2020
1/8 We’ve all had that moment as learners when we think we’ve detected a key physical exam finding, and upon returning with the attending: that rash, cool extremity, or tremor has gone away.
2/8 @VillarPrados told me a great catch he made his intern year. He was admitting a gentleman with syncope. He heard a loud systolic murmur during cardiac auscultation and ordered an echocardiogram.
3/8 He presented the patient and this exam finding to his attending hours later. When they arrived at bedside to examine the patient, the murmur disappeared! At this point, @VillarPrados is feeling meek and second guessing himself. 😳
Read 9 tweets
May 28, 2020
1/5 Myths in Medicine:
1.Docusate is an effective laxative
2.Oral iron requires TID dosing
3.HCQ for treatment of #COVID19
4. 𝗖𝗵𝗮𝗹𝗸 𝘁𝗮𝗹𝗸𝘀 𝗮𝗿𝗲 𝗲𝗮𝘀𝘆 𝗮𝗻𝗱 𝗲𝗳𝗳𝗼𝗿𝘁𝗹𝗲𝘀𝘀
2/5 The best #chalktalks are succinct, spontaneous, and seemingly breezy. But that does not mean they don’t require hard work! Anything that looks easy and effortless actually took hours of preparation and repetition. #PrepandReps
Read 5 tweets

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