Dimethyl Fumarate-Induced Takotsubo Cardiomyopathy in a Patient With Relapsing-Remitting Multiple Sclerosis.

Dimethyl fumarate (DMF) is an approved oral pharmacologic agent used in the treatment of relapsing-remitting multiple sclerosis (RRMS). Although commonly used in clinical practice, its mechanism of action remains largely unknown. Some frequent side effects associated with this drug are angioedema, hepatic injury, flushing, herpes zoster infection, and abdominal pain among others. A 47-year-old female presented with symptoms of an allergic reaction after initiating DMF therapy. She required intensive care unit admission due to an acute-hypoxic respiratory failure. A transthoracic echocardiogram (TTE) revealed apical ballooning and a left ventricular ejection fraction (LVEF) of 35%-40%. A coronary angiogram revealed no coronary artery disease. The diagnosis of takotsubo cardiomyopathy was made. The patient was managed with high-dose steroids and an epinephrine drip, in addition to a high-flow nasal cannula (HFNC) for respiratory support. At a three-month follow-up, a repeat TTE showed a resolution of the underlying takotsubo cardiomyopathy (CM) with no stunted myocardium and a normal ejection fraction (EF). Here, I highlight a life-threatening case of DMF-induced takotsubo CM and familiarize clinicians and patients with the need for close monitoring of symptoms when initiating disease-modifying drug (DMD) therapy.