A teaching moment please

[Wackie]

---

Members do not see this ad.

This is about cardiac enzymes and diagnosing MI.

When CK is elevated it simply represents muscle injury, yes? When troponin is elevated, it also represents muscle injury but is more specific to cardiac muscle? So elevated troponin means damage to the heart but not necessarily an MI? Or does elevated troponin always mean MI?
And how about the CK-MB index used to diagnose an MI? Or is the index only used when troponin is normal or barely bumped?

Any explanation is appreciated. 🙂

 

[BKN]

This is about cardiac enzymes and diagnosing MI.

When CK is elevated it simply represents muscle injury, yes? When troponin is elevated, it also represents muscle injury but is more specific to cardiac muscle? So elevated troponin means damage to the heart but not necessarily an MI? Or does elevated troponin always mean MI?
And how about the CK-MB index used to diagnose an MI? Or is the index only used when troponin is normal or barely bumped?

Any explanation is appreciated. 🙂

CK means muscle, CK-MB means cardiac muscle (mostly). CK-MB index is used to determine if the ratio of CK-MB to CK is more consistent with cardiac or skeletal muscle if both are elevated.

Troponin-I is has equal sensitivity, more specificity and stays elevated longer.

Therefore, for acute chest pain I only use the troponin-i. If the pain started more than 24 hours ago and I want to know whether it's still within a thromblytic or PCI intervention window, I'll add the CK-MB. If the troponin is elevated but the ck-mb has fallen back to normal it's probably too late.

 

[EctopicFetus]

Also Troponin-I can also be elevated in other processes specifically myocarditis as well as others, also Trops are cleared by kidneys so someone with ARF, CRF or ESRD may have chronically elevated trops but not very very high trops.

 

[southerndoc]

I'm not a big fan of the concept of "troponin leak." Almost every patient with a "troponin leak" actually has an NSTEMI. Exceptions are as Ectopic pointed out: myocarditis, traumatic injury, etc. However, one could argue that these patients are also suffering NSTEMI since they have infarcting tissue from their underlying process that is causing the release of troponin.

 

[BADMD]

I'm not a big fan of the concept of "troponin leak." Almost every patient with a "troponin leak" actually has an NSTEMI.

One of the residents on the cardiology service (as they refused to admit my patient) told me that the patient had a "troponin leak." When I asked what that meant, he said that the heart needed more oxygen than it was getting, thus there was a supply demand mismatch. Funny, I thought that is what I used to call "ischemia."

I think "Troponin leak" is cards speak for, "We're not going to cath this guy." No cath, no admit.

 

[WallowaWanderer]

I think "Troponin leak" is cards speak for, "We're not going to cath this guy." No cath, no admit.

 

[southerndoc]

I think "Troponin leak" is cards speak for, "We're not going to cath this guy." No cath, no admit.

Yea, "admit to medicine and we'll consult." Some of the cardiologists will actually pull the "it's ok to discharge them home, I'll see them later in the week." It's funny that when I insist they see them in the ED, and when they leave a note with their name in the chart, they never recommend sending them home!

Consultants will often recommend sending patients home to get out of a consult. They know it's the EP that would be sued if something goes wrong.

 

[WallowaWanderer]

Consultants will often recommend sending patients home to get out of a consult. They know it's the EP that would be sued if something goes wrong.

Wow, that sucks. 👎

 

[Jeff698]

Speaking of "troponin leaks", I had an interesting case while moonlighting the other night.

I had an elderly woman come in with RUQ pain that she said was from symptomatic cholelithiasis. Her surgeon was waiting for pre-op clearance of some pulmonary issues prior to surgery. I ordered another US and drew labs, including markers.

Her trop came back elevated. She had no chest symptoms whatsoever. No heaviness, sob, nausea...nothing. Just the same RUQ pain she'd had with her stones for the past week.

US report showed a small pericardial effusion.

I sat there thinking about that for awhile trying to figure out the etiology of that troponin. Obviosly, I admitted her, but it was still interesting. Her troponin peaked on the second value at around 1.9.

Things that make you go hmmmm. I haven't been back to that hospital since so I don't know how she did yet.

Take care,
Jeff

 

[southerndoc]

Most people who produce small amounts of troponin will often have signs of ongoing ischemia if you really ask them in detail. Some will report an episode of chest pain, shortness of breath, etc. a few days ago while exerting themselves. One of my most recent "troponin leaks" said he felt a little more winded than usual when exercising on the treadmill two days prior to coming to the ED for persistent vomiting, diarrhea, and dehydration.

Sometimes it's lab error. I've sometimes sent samples immediately after the positive troponin only to find that it's negative. If the potassium is a little higher than one would expect, and the lab doesn't comment on hemolysis, I will often send another sample. Even slight hemolysis not detected by the lab tech can cause a falsely elevated troponin.