Understanding Myocarditis Symptoms, Causes & Treatment

What is Myocarditis?

Myocarditis (心肌炎) is an inflammatory disease of the heart muscle, known as the myocardium. It can weaken the heart, lead to abnormal rhythms, and in severe cases, become a precursor to heart failure. Understanding this condition is a step forward in heart health awareness and management. This blog will illuminate the aspects of myocarditis, from its symptoms and causes to the treatment options available. 

Understanding the Causes of Myocarditis 

In Hong Kong's diverse environment, where seasonal flu and other viral infections are prevalent, understanding these causes is the first defense against myocarditis. The aetiology of myocarditis is multifaceted, with viral infections being the most common culprits.   Here's a detailed look at some of the known causes of myocarditis: 

> Infections 

• Viral Infections: These are the most common cause of myocarditis, particularly Coxsackievirus B. Other viruses that have been linked to myocarditis include influenza (flu), adenovirus, parvovirus B19, human herpesvirus 6, Epstein-Barr virus, cytomegalovirus, hepatitis C, HIV, and, more recently, SARS-CoV-2, the virus responsible for COVID-19. 
• Bacterial Infections: Less common than viral causes, but certain bacteria such as Staphylococcus, Streptococcus, and Borrelia burgdorferi (which causes Lyme disease) can cause myocarditis. 
• Parasitic Infections: Infection with parasites like Trypanosoma cruzi (which causes Chagas disease) and Toxoplasma gondii can result in myocarditis, especially in certain geographical regions. 
• Fungal Infections: Fungal causes are rare and usually occur in individuals with compromised immune systems. They can include fungi such as Candida and Aspergillus species. 

> Autoimmune Disorders 

• Autoimmune Reactions: The body's immune system may mistakenly attack the heart muscles, leading to inflammation. This can occur as a part of systemic autoimmune diseases like lupus (SLE), rheumatoid arthritis, or sarcoidosis. 

> Toxins 

• Drugs and Chemicals: Exposure to certain toxins, including alcohol, cocaine, certain chemotherapy drugs such as adriamycin and doxorubicin, and heavy metals like lead and arsenic, can cause myocarditis. 
• Allergic Reactions: Some people may have an allergic reaction to medications or environmental substances, leading to myocarditis. 

Other Causes 

• Vaccine Reaction: Very rarely, certain vaccines may trigger myocarditis, though the risk is often much lower than the risk of myocarditis from the diseases the vaccines prevent. 
• Idiopathic: In some cases, the cause of myocarditis remains unidentified, and it is classified as idiopathic myocarditis. 

Common Symptoms of Myocarditis 

Recognising myocarditis symptoms can be challenging as they often resemble those of other heart conditions. Detailed awareness of these symptoms is crucial for early diagnosis and prompt treatment. Here are some general symptoms that may be associated with myocarditis: 

• Fatigue: A common symptom due to the decreased efficiency of the heart to pump blood. 
• Fever: Often accompanies myocarditis, especially if it is related to an infectious cause. 
• Body Aches and Joint Pain: These non-specific symptoms can sometimes be present, particularly in the context of an infectious process. 
• Skin Rash: May accompany an acute viral infections or drug-induced allergic reaction 

Cardiac Symptoms 

• Chest Pain: This can be a sharp or stabbing discomfort or a feeling of pressure in the chest, often due to inflammation of the heart muscle and surrounding pericardium. 
• Palpitations: Irregular heartbeats or the sensation of the heart racing can occur when myocarditis affects the heart's electrical system. 
• Shortness of Breath: This may occur both during rest or physical activity due to the heart's reduced ability to circulate blood effectively. 
• Swelling/Edema: Fluid retention can cause swelling in the legs, ankles, feet and even around the eyes (periorbital edema). 

Severe Cases 

• Lightheadedness or Syncope: Feeling dizzy or fainting can occur due to a decrease in blood pressure or irregular heart rhythms. 
• Rapid or Abnormal Heart Rhythms: Severe myocarditis can lead to arrhythmias, which can be life-threatening. 
• Signs of Heart Failure: In severe cases, myocarditis can weaken the heart leading to heart failure, with symptoms such as severe shortness of breath, especially when lying down, and significant swelling. 

Symptoms in Children   

• Abdominal Pain: This is a common complaint among pediatric patients with myocarditis 
• Breathing Difficulties: This may be more noticeable in infants and young children. 
• Poor Feeding: Infants might show poor feeding or failure to thrive due to decreased cardiac output. 

Diagnosis of Myocarditis    

Diagnosing myocarditis involves a combination of medical history and clinical evaluation, electrocardiogram (ECG/EKG), imaging techniques like echocardiograms and MRIs, and sometimes, endomyocardial biopsies. In Hong Kong's advanced medical landscape, these diagnostic tools are readily available to doctors, ensuring accurate and timely diagnosis. 

Treatment Options for Myocarditis   

Myocarditis treatment focuses on addressing the underlying cause and relieving symptoms. The goal is to reduce heart inflammation, manage symptoms and prevent long-term complications. Treatment regimens may include medications like anti-inflammatories, heart medications e.g. beta-blockers, diuretics and ACE-inhibitors, antivirals, or antibiotics. Therapies such as corticosteroids or intravenous immunoglobulin are considered in more severe cases. Cardiac transplantation is an option for qualified patients with progressive heart failure deterioration despite optimal medical management.   

Living with Myocarditis: Lifestyle Changes and Management 

Living with myocarditis requires a comprehensive management plan that includes lifestyle changes. Patients are often advised to modify their diet, exercise appropriately, and monitor their symptoms closely. In Hong Kong, where lifestyle is fast-paced, such adjustments are essential for those recovering from myocarditis. 

Prevention of Myocarditis 

Prevention is always better than cure. Preventative measures for myocarditis include maintaining good personal and environmental hygiene, prior knowledge of the cardiac side-effects of medications, staying current with vaccinations, control of insect vectors such as mosquitoes and ticks, and avoiding known triggers especially for individuals with high allergy profile. Public health measures in Hong Kong also play a pivotal role in preventing outbreaks that could lead to myocarditis. 

Myocarditis is a complex condition that demands a nuanced understanding of its symptoms, causes, and treatments. With the proper knowledge and resources, individuals can manage and overcome myocarditis. As medical professionals in Hong Kong and beyond continue to advance their understanding and treatment of this condition, there is always hope for those affected.