AMI after low-dose IV epinephrine for anaphylaxis

Letters

CJEM 2006;8(6):387

AMI after low-dose IV epinephrine for anaphylaxis

To the editor: The letters1,2 in September's issue of CJEM responding to our Case Report on the use of IV epinephrine in anaphylaxis3 raise interesting questions. We agree that a 10-hour onset delay seems long, but penicillin remains a more likely cause of anaphylaxis than ibuprofen, which the patient had taken in the past, and regardless of the inciting agent, the case illustrates important points. We did not suggest that our patient suffered a large myocardial infarction. A troponin elevation to 2–3 times normal does not suggest major damage, but is consistent with infarction. Based on the minor nature of this infarct and its presumed pathogenesis, our cardiologists chose to do a CT angiogram because they believed the risks of invasive angiography were greater than the potential benefits in this young person without concomitant disease. All acute coronary syndromes (ACS) protocols recommend ASA in the presence of ST elevation; however, if in this situation (anaphylaxis with epinephrine-induced coronary vasospasm) occurs in the future, we would not necessarily administer ASA, since ASA and NSAIDs can exacerbate anaphylaxis.

We have no specific comments about Dr. Shah's letter2 as it illustrates the reason we wrote this case report. Our hope was that it would educate others about the potential harm associated with intravenous (IV) epinephrine. (This patient has been advised that she is never again to receive epinephrine.) We have found the same opinion split in our emergency department community and were surprised to find no definitive answer in the literature. We agree that, in all but extreme cases, intramuscular epinephrine is the correct choice and that the lateral thigh is the correct place. We recognize that this case report does not rule out a role for IV epinephrine in extreme anaphylaxis and shock, although the IV route is associated with a shorter action duration. (It is interesting to speculate that the shorter IV duration may have been less dangerous in a case like this.)

Steve Weiss, MD
Kyle Shaver, MD
Christopher Adams, MD
Department of Emergency Medicine
University of New Mexico
Albuquerque, NM

References

1. Maddison G. AMI after epinephrine [letter]. Can J Emerg Med 2006;8(5): 315.
2. Shah A. AMI after epinephrine [letter]. Can J Emerg Med 2006;8(5):315-6.
3. Shaver KJ, Adams C, Weiss SJ. Acute myocardial infarction after administration of low-dose intravenous epinephrine for anaphylaxis. Can J Emerg Med 2006 ;8(4):289-94.