Myocarditis
Myocarditis is an inflammation of the heart muscle (myocardium) that can be serious and, in some cases, fatal. While it can occur without noticeable symptoms—rendering it undiagnosed in many instances—when present, symptoms may include flu-like signs, chest pain, shortness of breath, and even loss of consciousness. The causes of myocarditis can be categorized into infectious, toxic, and immune-mediated types, with many cases remaining idiopathic, meaning no clear cause can be identified.
Notably, recent monitoring by health authorities has explored potential links between myocarditis and mRNA COVID-19 vaccinations, particularly in young adult males, though such cases are rare and typically resolve well with medical care. Diagnosis is complex, often requiring a range of tests to exclude other heart conditions. Treatment generally involves bed rest and may include medications to address inflammation, support heart function, or treat underlying infections. Preventive measures focus on minimizing exposure to known risk factors, such as practicing good hygiene and avoiding illegal drugs. Overall, understanding myocarditis is crucial for recognizing its potential seriousness and seeking timely medical attention.
Myocarditis
- ANATOMY OR SYSTEM AFFECTED: Cardiovascular system, heart
Definition
Myocarditis is an inflammation of the heart’s muscular wall, the myocardium. Although rare, it can be devastating. Myocarditis can occur with no symptoms and can remain undiagnosed.
Causes
Many cases of myocarditis have no identifiable cause and are called "idiopathic myocarditis." When a cause is identified, myocarditis falls into one of three categories: infectious, toxic, and immune-mediated.
Infectious myocarditis is caused by either a viral infection from viruses such as measles, rabies, or human immunodeficiency virus (HIV); a bacterial infection from bacteria such as diphtheria or Mycobacterium; or a fungal infection from Aspergillus or Candida.
Toxic myocarditis is caused by drugs such as chemotherapeutic drugs, lithium, or cocaine; by heavy metals such as copper, iron, or lead; by toxic substances such as arsenic, carbon monoxide, or other inhalants; and by physical agents such as electric shock or radiation.
Immune-mediated myocarditis is caused by an allergic reaction to penicillin or streptomycin; by alloantigens, including heart transplant rejection; and by autoantigens, including Chagas disease, scleroderma, or lupus.
Risk Factors
There are no known risk factors for developing myocarditis. However, after the development of the COVID-19 vaccine, the Centers for Disease Control began monitoring reports of cases of myocarditis occurring following vaccination. The CDC continues to actively study the relationship between the COVID-19 vaccination and myocarditis. Though rare, when these cases have been reported, they have occurred within several days of the patient receiving the second dose of the mRNA COVID-19 vaccine. The longer the interval between doses, the less likely the risk of myocarditis. The cases were most prevalent in young adult males, and the patients responded well to medical intervention, allowing them to recover quickly. As vaccines were developed to target specific variants of COVID-19, studies were undertaken to show how that might impact risk.
Symptoms
The symptoms of myocarditis vary from person to person, depending on the cause and the severity. Furthermore, some people have no symptoms and are thus asymptomatic. The following symptoms may appear slowly or suddenly: flu-like complaints, including fever, fatigue, muscle pain, vomiting, diarrhea, and weakness; a rapid heart rate; chest pain; shortness of breath and respiratory distress; and a loss of consciousness. Sudden, intense myocarditis can lead to congestive heart failure and death.
Screening and Diagnosis
The diagnosis of myocarditis is often difficult. There is no specific test for it. Many other causes of heart problems must be ruled out. To do this, a doctor will ask the patient about symptoms and medical history and perform a physical exam. Tests may include an electrocardiogram (ECG), which records the heart’s activity by measuring electrical currents through the heart muscle; a chest X-ray, which uses radiation to take pictures of structures inside the body; a cardiac enzyme blood test (because, in some cases, certain enzymes are elevated); an echocardiogram, which uses high-frequency sound waves, or ultrasound, to examine the size, shape, and motion of the heart; a biopsy (the removal of a sample of heart tissue to test for infection); and magnetic resonance imaging (the use of magnetic waves to take pictures of structures inside the body).
Treatment and Therapy
The universally recommended therapy for myocarditis is bed rest, no physical activity, and supplemental oxygen. Corticosteroids may be given to help inflammation, and the patient will most likely be admitted to a hospital.
Specific treatment is directed at the underlying cause, if possible. For instance, if the cause is a bacterial infection, the doctor will prescribe antibiotics; if the cause is viral, the doctor will prescribe antiviral agents. Immunosuppressive therapy may be used if the myocarditis is caused by an autoimmune disorder such as lupus or scleroderma.
If heart failure symptoms are present, the doctor will prescribe medications to support the function of the heart. These medications include diuretics, ACE inhibitors, beta-blockers, and antiarrhythmic agents. Additionally, a defibrillator, which helps maintain the normal rhythm of the heart, may be implanted into the patient’s chest. Severe cases may require a cardiac transplant.
Prevention and Outcomes
Myocarditis is difficult to prevent. To help reduce the chance of getting myocarditis, one should reduce exposure to identified causes. Some examples of prevention include practicing good hygiene to avoid the spread of infection (for example, washing one’s hands regularly), always using latex condoms during sexual intercourse, having monogamous sex, and avoiding illegal drugs.
Bibliography
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