A Diagnostically Challenging Infusion Reaction - Kounis, Takotsubo, or the ATAK!

Awoman in her 60s with a history of insulin-dependent diabetes mellitus, hypertension, chronic kidney disease, and multiple myeloma (MM) presented to the emergency department after she had experienced transient "chest discomfort" and dyspnea 1 hour into her first chemotherapy infusion with anti-CD38 antibody (daratumumab). She was given racemic epinephrine, diphenhydramine, and methylprednisolone to treat a presumptive hypersensitivity reaction. Her initial 12-lead electrocardiogram (ECG) showed sinus tachycardia, and her troponin T level was 0.06 ng/mL (collected 10 minutes after racemic epinephrine administration). On admission to the floor, she remained free of chest pain, and her vital signs and physical examination findings were normal. Results of a complete blood cell count and basic metabolic panel were normal, and the repeated troponin T measure was elevated to 0.4 ng/mL (collected 14 hours after racemic epinephrine administration). The patient remained free of chest pain, and the 12-lead ECG was repeated (Figure). The third troponin T measure was found to be 0.37 ng/mL (18 hours after racemic epinephrine administration).