Signs and symptoms
The signs and symptoms associated with myocarditis are varied, and relate either to the actual inflammation of the myocardium or to the weakness and dysfunction of the heart muscle that is secondary to the inflammation. While myocarditis may develop over periods ranging from hours to months, patients typically present with signs and symptoms that resemble heart failure, including the following:
Since myocarditis is often due to a viral illness, many patients experience symptoms consistent with a recent viral infection including a fever, rash, loss of appetite, abdominal pain, vomiting, diarrhea, joint pains, and easily becoming tired. Additionally, myocarditis is often associated with pericarditis, and many people with myocarditis present with signs and symptoms that suggest myocarditis and pericarditis at the same time.Children primarily present with the aforementioned symptoms associated with a viral infection. Since they overlap with many other illnesses, this can make it more challenging to diagnose myocarditis in younger patients. Later stages of the illness can involve the respiratory system and lead to increased work of breathing. These are often mistaken for asthma.Myocarditis can be distinguished as either fulminant or acute based on the severity of symptoms on presentation, as well as the time course over which symptoms develop and persist. This categorization can help predict the treatment, outcomes, and complications of myocarditis. Fulminant myocarditis is defined as sudden and severe myocarditis that is associated with signs and symptoms of heart failure while at rest.
This can involve the use of inotropes, or medications that make the heart contract with greater force, as well as antiarrhythmic drugs such as adenosine or carvedilol. In patients that have stable and adequate heart function, further treatments are based on heart failure guidelines. ACE inhibitors can have a protective benefit to the heart, so they are typically used in any patient with symptomatic myocarditis. Simultaneously, beta blockers are used in patients that can tolerate their heart beating at a slower rate. Shortness of breath at rest and swelling can be relieved with diuretics such as furosemide, and the addition of aldosterone receptor blockers can augment the diuresis while preventing the excess loss of potassium. In patients with symptoms while resting, additional medications can be added such as digoxin. Mechanical support
Mechanical support is used in cases of myocarditis in which medications alone do not lead to adequate heart function and the body requires additional support to achieve organ perfusion. Myocarditis cases that require mechanical circulatory support are categorized as fulminant by definition. People that require additional support with their heart function can benefit from the use of ventricular assist devices like intra-aortic balloon pumps. In people with myocarditis severe enough to cause cardiac arrest, extracorporeal membrane oxygenation (ECMO) is used to adequately pump blood and provide oxygen if needed. Both ventricular assist devices and ECMO can be used as bridge therapy until heart transplantation in patients that are candidates. Heart transplantation is reserved for those that do not respond to the aforementioned conventional medical therapies.