Myocarditis I: Introduction

Myocarditis is an inflammation of the myocardium, the heart's muscular layer, caused by various infectious and non-infectious factors.

Infectious causes include viruses like Coxsackievirus A and B, influenza A, and bacteria such as Streptococcus pyogenes and Mycoplasma pneumoniae.

Fungi like Aspergillus and parasites such as Trypanosoma cruzi can also cause myocarditis.

Non-infectious causes include autoimmune disorders such as systemic lupus erythematosus, radiation therapy, and chemotherapy drugs like doxorubicin.

Next, the pathophysiology of myocarditis involves a causative agent, such as a virus or bacteria, invading the myocytes and leading to cellular damage and necrosis.

This damage activates the body's immune response, releasing cytokines and oxygen-free radicals that attempt to eliminate the infectious agent but also contribute to myocardial damage.

As the infection progresses, an autoimmune response may mistakenly target the body's myocardial cells, leading to further destruction of myocytes and heart dysfunction.