Toxic myocarditis presenting as an acute coronary syndrome

Abstract

Background Acute myocarditis is one of the causes of acute non-ischemic myocardial injury mimicking acute coronary syndrome (ACS) on presentation. It is usually underdiagnosed due to the non-specificity of presenting symptoms, elevated troponin levels, and abnormal ECG (electrocardiogram) findings. Delayed contrast-enhanced cardiac MRI (CMR) is known as the gold standard imaging modality for differentiating acute non-ischemic myocardial injury from infarcted myocardium. The most frequent cause of myocarditis is viral infections, but further infrequent causes include other infectious pathogens, toxins, hypersensitivity drug reactions, and autoimmune diseases. Cannabis is one of the most abused illicit and recreational drugs in the world among adolescents and adults. Also, many reports of marijuana-associated cardiovascular risks have been established previously, mainly presenting as arrhythmias, myocardial infarction, and myocarditis. Case presentation A 19-year-old female, complaining of radiating chest pain to the left arm and jaw, along with associated sweating for 1 day. Initial work-up showed elevated troponin levels with ST segment elevation on ECG. On further investigation, CMR showed findings of myocarditis and negative virology work-up led to a work-up of proper history, which revealed marijuana abuse, with a history of consumption 3 days before presentation. Hence, it was diagnosed as toxic myocarditis secondary to presumed cannabis abuse and treated for same. Conclusions Non-ischemic myocardial injury causes like myocarditis should be considered in young patients especially, who are presenting to emergency with ACS. CMR should be used as a first line diagnostic imaging modality (based on its availability) in cases mimicking an ACS or suspected myocarditis, especially in young patients. Though viral etiology is considered the most common cause of myocarditis, less common causes such as toxic myocarditis must be considered in cases of young individuals presenting with ACS in an emergency.