Myocarditis Symptoms and Clinical Presentations

Myocarditis often begins with a prodromal phase marked by infection symptoms. The clinical manifestations can vary significantly depending on the extent of myocardial involvement and the specific type of infection.

Common Prodromal Symptoms

When the prodromal phase involves an upper respiratory tract infection, patients may experience fever, sore throat, and cough. In cases where the initial infection is gastrointestinal in nature, symptoms can include diarrhea, vomiting, muscle aches, and fever. These early signs can easily be mistaken for common viral illnesses, making early detection of myocarditis challenging.

Typical Cardiac Symptoms

Mild Myocarditis

Not all cases of myocarditis present with clear symptoms. In milder forms, patients may only report palpitations or a general feeling of fatigue. This lack of distinct symptoms can lead to underdiagnosis or misdiagnosis.

Moderate to Severe Myocarditis

As the inflammation affects a larger portion of the myocardium, patients commonly report palpitations, chest tightness, and shortness of breath. If the inflammation extends to the pericardium or pleura, sharp chest pain may develop, often worsening with deep breaths or lying down.

Severe Complications

In severe cases, myocarditis can rapidly progress to life-threatening conditions such as cardiogenic shock or sudden cardiac death. These complications often follow the initial prodromal symptoms and may present as severe dyspnea, peripheral edema, syncope, or even sudden loss of consciousness. The underlying causes are typically linked to extensive acute myocardial injury, which can result in severe arrhythmias, heart failure, and hemodynamic instability.

Clinical Classification of Myocarditis

Based on clinical presentation, myocarditis can be categorized into several types, including mild, subclinical, insidious progressive, acute dilated cardiomyopathy-like, atrioventricular block, myocardial infarction-mimicking, and sudden death types. The wide variability in symptoms makes diagnosis based solely on clinical features difficult, often necessitating further diagnostic testing such as cardiac imaging, biomarker analysis, and electrocardiography.