Wednesday, August 5, 2015

Epigastric Abdominal Pain and Vomiting

No details important to the diagnosis are left out, but the details are intentionally vague to preserve anonymity.

The details need not be specific for an important Learning Point.

A male in his 30's presented with epigastric pain and vomiting.  There was no chest pain, SOB, jaw pain, or shoulder pain.  More specific history was not available.   The abdominal exam was unremarkable, but the etiology of the pain was uncertain, so a CT of the chest, abdomen, and pelvis was done.

Here is the part of the CT that showed the heart:
Notice the posterior and lateral myocardial wall is dark.  This is because there is no radiodense (and therefore light colored on scan) contrast getting to that myocardium.  Compare it with the well-perfused (light-colored) myocardium of the anterior wall and septum.

 Here I have annotated the poorly perfused myocardium with yellow arrows:

Here is an image slightly farther down, toward the inferior wall:


Here is the inferior wall:




The yellow lines encircle the infarcting area of the inferior wall.
That last bit of contrast is blood in the ventricle.  A more inferior cut of CT would show the most inferior (and ischemic) part of the inferior wall.



This was immediately diagnosed as a myocardial infarction, and an ECG was recorded:
Inferior-Posterior STEMI, as predicted by the CT scan!


Here is the post-PCI ECG:
Notice the very large T-wave in V2.  This is a "posterior reperfusion T-wave."  It occurs because we are recording posterior T-wave inversion (reperfusion T-wave) from anterior, so that it has positive voltage rather than negative.  It is then added to the anterior positive T-waves and makes them extra large.


Learning Point:

This patient with no CP, no SOB, no jaw or shoulder pain was having a STEMI.

This is why I always record an ECG for epigastric pain.  Inferior MI not uncommonly presents as epigastric pain, usually without tenderness.  That said, the vast majority of epigastric pain is abdominal.

If I record a non-diagnostic ECG for epigastric pain, and do not find a clearly ischemic ECG, I am much less likely to further evaluate the patient for cardiac ischemia.  The pretest probability of cardiac ischemia is far lower with epigastric pain than with chest pain.  Thus, I record the ECG to look for specific signs of ischemia, and the ECG must be very suggestive of ischemia to proceed with further coronary workup.

In other words, if you record ECGs for all kinds of atypical symptoms (as I do), you must also be judicious is interpreting the ECG.  You will find many abnormal but non-diagnostic findings.  If all of them lead to an exhaustive workup, as you may undertake in a patient with chest pain, the yield will be very low.

So when you record an ECG for such symptoms, you are looking especially for the obvious STEMI.

Any test done in the setting of a low pre-test probability must have high specificity in order to have a reasonable positive predictive value.  

See these cases of posterior reperfusion T-waves.

See here a case of subendocardial ischemia diagnosed on CT scan.

3 comments:

  1. Chest X-ray, and ECG, for all patients with epigastric pain... Always... No exception... But pregnant woman...

    ReplyDelete

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