The causes of heart muscle inflammation (myocarditis) can be many and varied. An infection of the muscle layer of the heart can be caused by microorganisms such as bacteria or viruses, in which case it is known as infectious myocarditis. However, if the cause is a toxic substance, it is called a toxic form.
A cold can be caused by a viral or bacterial infection. This infection can also reach the heart muscles, where it can lead to an inflammation called myocarditis. It is estimated that 1 to 5% of all viral infections involve the heart.
The most common viral pathogen is the Coxsackie virus. But also the parvovirus B19, which causes rubella, can cause myocarditis. The same applies to the human herpes virus and adenovirus.
The most common bacterial triggers are Corynebacterium diphtheriae (pathogen of the disease diptheria), Borrelia burgdorferie (often transmitted by ticks) and β-hemolytic streptococci. Myocarditis after influenza is similar to that after a cold. Possible triggering pathogens can be viruses as well as bacteria, whereby infection by viruses is much more common.
Coxsackieviruses are particularly common in people with myocarditis. Of other pathogens, it is mainly those suffering from an immune deficiency that are affected. Here, a flu-like infection can spread more quickly to the entire body and thus also damage the heart.
Due to the severity of the complications of myocarditis, a flu-like infection should be avoided for at least a week without any sporting activity. In this context, the most frequent reason for this form of infection is increased alcohol consumption, the intake of heavy metals and the possibility of side effects of drugs such as chemotherapeutic agents for cancer, sleeping pills and anaesthetics (barbiturates) or psychotropic drugs. Furthermore, a pre-existing autoimmune disease can also be responsible for myocarditis. Diseases such as sarcoidosis, systemic lupus erythematosus, scleroderma or vascular inflammation (vasculitis), in which the human immune system is directed against the body’s own structures, sometimes attack the heart muscle and cause the destruction of muscle tissue in the course of an inflammatory reaction. Finally, there is the idiopathic form of myocarditis, in which there is no identifiable cause for the inflammatory process.
