Atypical Presentation of an Acute MI
A 68 year old female presented to the ER with complaints of abdominal pain and vomiting for three days. Past medical history was significant for end stage renal disease on hemodialysis, high blood pressure, diabetes, and high cholesterol.
Her past surgical history was significant for bilateral below the knee amputations (BKA), coronary artery bypass graft (CABG), and amputations of two fingers on her left hand.
The patient was worked up as a case of abdominal pain, we drew the regular labs, CBC, BMP, amylase, and lipase, and we also gave her oral contrast to drink in preparation for an abdominal CT. We also gave her pain and nausea medication. My initial impression as I assessed her was that she was definitely very sick. She could not tell me much about her history, most of we got from her prior visit records, and I was unable to ascertain when her last dialysis appointment had been. I placed her on the cardiac monitor because I was concerned about her past cardiac history, and because she looked really sick. I also obtained an EKG and an accucheck.
Her initial lab results revealed elevated BUN and creatinine values as expected, and her electrolytes were also out of whack. Most significantly her potassium level was markedly elevated at 7.0.
I have seen physicians manage hyperkalemia in different ways. The attending that night elected to use Kayexalate PO and 1 amp Calcium chloride IV push. Knowing that she was a renal patient, and given the potential cardiac toxicity of calcium chloride, I verified the order with the doc to make sure this was what he wanted to do. I injected the dose into a small 50ml bag of 0.9% NSS and infused it over 20 minutes.
An hour after I had given her the Kayexalate and the calcium chloride had completed infusing, the patient became very restless and agitated, stating she could not breathe and felt "not right." I quickly obtained an accucheck, an EKG, and a set of vital signs. I placed her on 2L of oxygen. All her signs were stable, there were no changes in her EKG, and her accucheck was 146. She was midly tachycardic on the heart monitor, but she was very diaphoretic and unable to verbally respond to my questions. Very shortly after this the patient decompensated rapidly, appeared to go into a tonic clonic seizure with foaming at the mouth, and in a matter of minutes she became completely unresponsive. We could not obtain a BP or a pulse ox reading, but all pulses remained palpable. We intubated her to protect her airway, drew another chemistry panel, and also drew a set of cardiac enzymes. The patient progressed into a bradycardic arrest and we had to perform CPR.
After several doses of atropine and epinephrine we were able to obtain a pulse, a BP, and she begun to perfuse and we could get a pulse ox reading. Her repeat potassium level drawn just before we intubated her came back at 5.9, and her troponin came back at 3.8.
At this point my shift was ending and I had to hand her care over to another nurse so she could be transferred to the ICU. When I came back to work after two nights, I looked up her chart and got an update.
Her second and third set of cardiac enzymes had troponins trending upwards with the third troponin being 83. Her abdominal CT was unremarkable, and her potassium level was down to 4.8. She was being managed as having a non-ST elevation MI (NSTEMI) secondary to hyperkalemia and acidosis.
I have reflected a lot on this case, being that this was the first time I watched a patient assigned to me decompensate so rapidly.
Things I'm glad I did:
- Obtained a baseline EKG and accucheck on arrival even though they weren't ordered
- Placed her on a cardiac monitor even though it was not ordered
Things I wonder about:
- Did the calcium chloride accelerate or trigger whatever cardiac event was happening leading to an MI, or was her body building up to the MI all on its own?
- Had we drawn a set of cardiac enzymes with her initial labs, would the troponin have been positive, and would this have made a difference in the final outcome?
- Would it have helped if we had been able to ascertain for a fact that she had missed a dialysis appointment (which I suspect she had)? If we had dialyzed her emergently on arrival to the ER, would it have made a change in the outcome?
The patient remained stable in the ICU for a few days and was subsequently extubated and transferred to a regular floor.