Friday, February 26, 2016

"I have food poisoning"

This patient in her 40's with type 1 DM presented with 16 hours of vomiting (x 10) and diarrhea (liquid/loose x 10).  She came to triage complaining of "food poisoning."  There was some diffuse abdominal pain, but no chest pain or shortness of breath.  She was tachycardic to 120 and had no Kussmaul respirations.  Her abdomen was diffusely tender but without guarding.

The intern presented the patient and a plan to check a chemistry panel, and to give antiemetics and fluids.

I said: "you better order an EKG; you never know when a vomiting patient, especially a diabetic, is having an MI."

Here is her ECG:
There is anterolateral ST elevation, with well-formed QS-waves in V1-V3.  This is diagnostic of a subacute anterolateral STEMI.
She did have a mild ketoacidosis as well.

At angiography, there was a 100% thrombotic occlusion of the mid (not proximal) LAD and had evidence of prolonged occlusion (subacute MI).  The initial troponin I was 88 ng/mL (88,000.00 ng/L), confirming prolonged occlusion and large MI.  The highest troponin, after artery opening, was 222 ng/mL.  Echo showed EF of 12% and multiple wall motion abnormalities.  Angiogram showed severe downstream microocclusion.

Next day ECG:
Persistent ST Elevation and Long QT.
Such persistent ST elevation with QS-waves is associated with mechanical complictions (e.g., myocardial rupture) and with development of LV aneurysm.

At 48 hours:
ST Elevation remains persistent



Learning Points:

1. ECGs are cheap and noninvasive.  As long as you know how to keep from over-interpreting ECGs in patients with a low pretest probability, it can't hurt to order one in nearly any patient who has acute chest or abdominal symptoms.

2. A clearly diagnostic ECG is diagnostic even when there are no clearly ischemic symptoms.  It may even be diagnostic when the patient has no symptoms!

Here is a case of a patient whose only symptom was hand numbness: 

Spontaneous Reperfusion and Re-occlusion - My Bad Thinking Contributes to a Death







6 comments:

  1. Dear Dr. Smith,

    Thank you very much for another excellent case. I should note that, in women nausea and vomiting can be a quite atypical, yet very important sign of myocardial ischemia.

    What was the outcome of this unlucky patient ?


    ReplyDelete
    Replies
    1. She is doing ok, but with very poor ejection fraction. Amazingly, did not have shock or severe heart failure.

      Delete
  2. How much was her potassium level? Looks like there is mild widening of qrs?

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    Replies
    1. Raghavendra,
      You are right that there is an intraventricular conduction delay (QRS = 124 ms), and good thought about K! But it was 3.9 mEq/L.
      Steve

      Delete
  3. Given the atypical (for acute STEMI) clinical features, and by seeing the first ECG, I think the differential diagnosis should have been between STEMI and LV aneurysm. Did the Twave ampl/QRSampl rules have been applied in this case?
    According to my calculations the sum is 0.30 and the maximum ratio is equal to 0.45 in V1 (but also greater than 0.36 in V2 and V3, but not in V4); by the way the calculations correctly predicts STEMI by both rules despite the long lasting symtoms (if we assume that the beginning of vomiting and diarrhea is the beginning of acute MI). Many thanks.
    Mario Parrinello

    ReplyDelete
    Replies
    1. Mario,
      You are exactly right that LV aneurysm is on the differential. But the ratio was so clearly far above 0.36 that I did not even mentiong it.
      In V2, the T/QRS ratio is 3.5/4.5 which is about 0.78.
      Steve

      Delete

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