Myocarditis
Disease Details
Family Health Simplified
- Description
- Myocarditis is the inflammation of the heart muscle, often caused by viral infections, leading to symptoms such as chest pain, fatigue, and arrhythmias.
- Type
- Myocarditis is an inflammatory condition of the heart muscle, typically caused by infections (most often viral), autoimmune diseases, or exposure to certain toxins and drugs. It is not classified under genetic diseases and does not have a specific pattern of genetic transmission. However, a genetic predisposition may influence an individual's susceptibility to infections or autoimmune responses that could lead to myocarditis.
- Signs And Symptoms
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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. 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. More specifically, fulminant myocarditis is characterized by a distinct, rapid onset of severe heart failure symptoms, such as shortness of breath and chest pain, that develop over the course of hours to days. Additionally, treatment requires the use of medications or mechanical devices to improve heart function.Acute non-fulminant myocarditis has a less distinct onset in contrast to fulminant myocarditis, and evolves over days to months. While the symptoms of acute myocarditis overlap with those of fulminant myocarditis, they do not typically occur at rest, and treatment does not require the use of mechanical circulatory support. - Prognosis
- The prognosis associated with myocarditis is stratified by the severity and time course along which symptoms develop. In addition to symptom severity, there are also several indicators of heart function that can be used to predict patient outcomes, many of which are part of the standard evaluation of patients presenting with cardiovascular dysfunction. Most people with myocarditis have an uncomplicated, self-limited and mild course while making a full recovery. However, those with myocarditis that present with a decreased ejection fraction, or those who present with heart failure, advanced atrioventricular block, with sustained ventricular arrhythmias or with hemodynamic instability have a worse prognosis with an increased risk of death or need for heart transplantation.An electrocardiogram is one of the most common screening tools used in cases of suspected cardiac pathology, such as myocarditis. The findings that correlate with poorer outcomes are non-specific and include widened QRS complexes and QT intervals, partial or complete atrial-ventricular heart block, and malignant ventricular arrhythmias like sustained ventricular tachycardia or ventricular fibrillation. Electrocardiogram findings of ST elevations with upward concavity and an early repolarization pattern, however, were associated with a better cardiovascular prognosis in general.In cases of acute myocarditis, cardiac magnetic resonance imaging can reveal several prognostic indicators that, similar to ECGs, are non-specific and reflect poorer cardiac physiology. Late gadolinium enhancement on cardiac MRI demonstrates perturbations in extracellular volume as a result of cell necrosis or edema, and is significantly associated with increases in all-cause mortality, cardiovascular mortality, and major adverse cardiovascular events. The association was strongest with any late gadolinium enhancement, but remained true for findings of anterolateral-specific enhancement. A similar relationship was found between a left ventricular ejection fraction < 50%, increased mortality, and increased major adverse cardiovascular events.Myocarditis has been reported to be a major cause of sudden cardiac death (SCD) in infants, adolescents, and young adults, but the reported rates show wide variation (1 to 14 percent) among young people depending on differences in SCD definition and classification/ definition of myocarditis post-mortem as well as heterogeneity of study populations.In fulminant myocarditis, in which an inflammatory cytokine storm occurs, cardiac functions decline rapidly and the death rate is high.
- Onset
- Myocarditis typically has an acute onset. Symptoms can appear suddenly and may include chest pain, shortness of breath, fatigue, and palpitations.
- Prevalence
- The prevalence of myocarditis, which is the inflammation of the heart muscle, can be difficult to determine precisely due to its varied presentation and often subclinical nature. However, estimates suggest that myocarditis occurs in about 10 to 20 cases per 100,000 people globally each year.
- Epidemiology
- The prevalence of myocarditis is estimated to be about 1-10 cases per 100,000 persons per year, with higher estimates at 22 cases per 100,000 persons annually. The highest incidence of myocarditis is seen in men between the ages of 20 and 40. Fulminant myocarditis, the most severe subtype, has been shown to occur in up to 2.5% of known myocarditis presentations. When looking at different causes of myocarditis, viral infection is the most prevalent, especially in children; however, the prevalence rate of myocarditis is often underestimated as the condition is easily overlooked and is sometimes asymptomatic. Viral myocarditis being an outcome of viral infection depends heavily on genetic host factors and the pathogenicity unique to the virus. If one tests positive for an acute viral infection, clinical developments have discovered that 1-5% of said population may show some form of myocarditis.In regard to the population affected, myocarditis is more common in pregnant women, children, and those who are immunocompromised. Myocarditis, however, has shown to be more common in the male population than in the female. Multiple studies report a 1:1.3-1.7 female-male ratio of prevalence of myocarditis. In young adults, up to 20% of all cases of sudden death are due to myocarditis. Young males specifically have a higher incidence rate than any other population due to their testosterone levels creating a greater inflammatory response that increases the chance of cardiac pathologies. While males tend to have a higher risk of developing myocarditis, females tend to display more severe signs and symptoms, such as ventricular tachycardia and ventricular fibrillation, but do so at an older age. Among patients with HIV, myocarditis is the most common cardiac pathological finding at autopsy, with a prevalence of 50% or more.Myocarditis is the third most common cause of death among young adults with a cumulative incidence rate globally of 1.5 cases per 100,000 persons annually. Myocarditis accounts for approximately 20% of sudden cardiac death in a variety of populations, including adults under the age of 40, young athletes, United States Air Force recruits, and elite Swedish orienteers. With individuals who develop myocarditis, the first year is difficult as a collection of cases have shown there is a 20% mortality rate.
- Intractability
- Myocarditis is not inherently intractable. The severity and outcome depend on the underlying cause, timely diagnosis, and appropriate treatment. Some cases resolve with medical management and rest, while others may lead to chronic heart issues or require more intensive interventions, such as medications or even heart transplantation. Early detection and treatment are crucial for better outcomes.
- Disease Severity
- Myocarditis can vary in severity. Some people experience mild symptoms and recover fully, often without needing extensive treatment. However, others might develop severe complications, such as heart failure, arrhythmias, or cardiogenic shock, which can be life-threatening and may require hospitalization or advanced medical interventions. The severity largely depends on the underlying cause, the promptness of diagnosis, and the effectiveness of the treatment received.
- Healthcare Professionals
- Disease Ontology ID - DOID:820
- Pathophysiology
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Myocarditis is an inflammation of the myocardium, the heart muscle. Its pathophysiology involves the infiltration of inflammatory cells into the myocardium, leading to myocyte necrosis and cardiac dysfunction.
1. **Infection:** Often caused by viral infections (e.g., Coxsackievirus, adenovirus), the pathogen directly infects myocardial cells, triggering an immune response.
2. **Autoimmunity:** The initial infection may lead to molecular mimicry, where the immune system mistakenly attacks cardiac tissues, perpetuating inflammation even after the pathogen is cleared.
3. **Toxins and Drugs:** Certain medications and toxins can cause direct myocardial injury and inflammation.
4. **Immune Response:** Both innate and adaptive immune responses are activated, leading to the release of cytokines and further recruitment of inflammatory cells.
This process can result in varied clinical manifestations, from mild symptoms to severe cardiac dysfunction, including heart failure and arrhythmias. - Carrier Status
- Myocarditis does not have a carrier status. It is an inflammatory condition of the heart muscle (myocardium) often caused by infections, immune system disorders, or exposure to toxic substances. Unlike genetic diseases, it is not inherited and doesn't involve a carrier state.
- Mechanism
- Most forms of myocarditis involve the infiltration of heart tissues by one or two types of pro-inflammatory blood cells, lymphocytes and macrophages plus two respective descendants of these cells, NK cells and macrophages. Eosinophilic myocarditis is a subtype of myocarditis in which cardiac tissue is infiltrated by another type of pro-inflammatory blood cell, the eosinophil. Eosinophilic myocarditis is further distinguished from non-eosinophilic myocarditis by having a different set of causes and recommended treatments.The pathophysiology of viral myocarditis is not well understood, but it is believed to involve cardiotropic viruses (viruses with a high affinity for the heart muscle) gaining entry to cardiac muscle cells, usually via binding to a transmembrane receptor. Over approximately the next 1–7 days the virus replicates and causes inflammation leadings to necrosis and apoptosis of cardiac muscle cells (myocytes) and activation of the innate immune system. Over the next 1–4 weeks, viral replication continues with subsequent activation of the acquired immune system leading to T cell infiltration and the formation of antibodies, including possibly auto-antibodies. Over the next few months to years, this process either resolves and concludes with viral clearance or it may progress to cause permanent heart damage such as dilated cardiomyopathy, ventricular dysfunction or other cardiomyopathies. Coxsackie B, specifically B3 and B5, has been found to interact with coxsackievirus-adenovirus receptor (CAR) and decay-accelerating factor (DAF). However, other proteins have also been identified that allow Coxsackieviruses to bind to cardiac cells. The natural function of CAR and mechanism that the Coxsackievirus uses to infect the cardiac muscle is still unknown. The mechanism by which coxsackie B viruses (CBVs) trigger inflammation is believed to be through the recognition of CBV virions by Toll-like receptors.The binding of many types of coronaviruses, including the SARS-CoV-2 virus, through ACE2 receptors present in heart muscle may be responsible for direct viral injury leading to myocarditis. In a study done during the 2002-2004 SARS outbreak, SARS viral RNA was detected in the autopsy of heart specimens in 35% of the patients in the Toronto, Canada area who had died due to SARS. It was also observed that an already diseased heart has increased expression of ACE2 receptor contrasted to healthy individuals which may lead to greater viral infiltration in the heart muscle. Hyperactive immune responses in COVID-19 patients may lead to the initiation of the cytokine storm. This excess release of cytokines may lead to myocardial injury. In addition to direct cardiac myocyte (heart muscle cell) damage due to SARS-CoV-2 viral infiltration and inflammation, there are other suspected mechanisms that Covid-19 may indirectly cause myocarditis. During COVID-19, the other indirect mechanisms thought to contribute to myocarditis include: oxygen supply-demand mismatch to the heart muscle leading to myocardial (heart muscle) injury; microvascular thrombi, or blood clots in the small blood vessels of the heart causing injury; the systemic hyperinflammatory state in Covid-19 leading to heart muscle injury; or the virus causing indirect damage to the heart by inducing auto-immune mediated damage to the heart muscle (and frequently other organs).
- Treatment
- While myocarditis has many etiologies and a variable constellation of signs and symptoms, many causes do not have a specific treatment thus the primary focus is on supportive care and symptom management. In some cases of biopsy-proven myocarditis, the causative cell type may indicate condition specific treatments that are beneficial. These treatments typically consist of corticosteroids, or immunosuppressants. Eosinophilic myocarditis, giant cell myocarditis and cardiac sarcoidosis are usually responsive to immunosuppressive treatments; in the form of glucocorticoids with or without azathioprine and cyclosporine. Some of these immune mediated forms of myocarditis require an extended course (maintenance course) of immunosuppressive therapy. It is recommended to rule out drugs and parasites as potential causes of eosinophilic myocarditis as these common causes of the variant can be effectively treated with discontinuation of the offending drug or specific anti-parasitic treatment respectively. Empiric IV glucocorticoids are indicated in acute myocarditis with cardiogenic shock, heart failure, ventricular arrhythmias or high degree AV block that is suspected due to auto-immune disease; but the European Society of Cardiology also recommends subsequent viral genome testing of endomyocardial biopsy specimens due to risk of viral activation, which may necessitate discontinuation of immunosuppression therapy.In a majority of cases, the main therapies are used to support patients and are dependent on the severity of symptoms and the time course across which myocarditis develops. Supportive therapies can be divided into two broad categories, medications and mechanical support.
- Compassionate Use Treatment
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For myocarditis, compassionate use treatments, off-label, or experimental treatments may include:
1. **Intravenous Immunoglobulin (IVIG)**: Sometimes used off-label for its potential immune-modulating effects.
2. **Immunosuppressive Therapy**: Drugs like azathioprine, mycophenolate mofetil, or cyclosporine may be used off-label in specific cases.
3. **Monoclonal Antibodies**: Some monoclonal antibodies, such as infliximab, may be considered for experimental use.
4. **Interferons**: Investigated for their antiviral and immunomodulatory properties in myocarditis.
5. **Stem Cell Therapy**: An experimental approach aiming to repair damaged myocardium.
6. **Specific Antiviral Drugs**: These may be considered in cases where myocarditis is linked to a viral infection.
Participation in clinical trials may also be an option for accessing experimental treatments. The choice of therapy typically depends on the underlying cause and severity of the myocarditis, as well as the patient's overall health. - Lifestyle Recommendations
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Lifestyle recommendations for managing and preventing myocarditis typically include:
1. **Rest and Recovery**:
- Adequate rest is crucial to allow the heart to heal, especially during the acute phase. Avoid strenuous activities until cleared by a healthcare provider.
2. **Healthy Diet**:
- Consume a balanced diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats to support overall cardiovascular health.
3. **Avoid Alcohol and Tobacco**:
- Refrain from smoking and limit alcohol intake, as both can exacerbate heart conditions.
4. **Regular Monitoring**:
- Keep regular appointments with your healthcare provider to monitor heart function and manage symptoms.
5. **Medications Adherence**:
- Follow prescribed medication regimens strictly, including anti-inflammatory drugs, if recommended.
6. **Manage Stress**:
- Engage in stress-reducing activities such as yoga, meditation, or moderate exercises like walking, as advised by your doctor.
7. **Hydration**:
- Stay well-hydrated, but consult your doctor about appropriate fluid intake, especially if heart function is compromised.
8. **Avoid Infections**:
- Practice good hygiene and stay updated on vaccinations to reduce the risk of infections that could trigger myocarditis.
Always consult your healthcare provider for personalized recommendations based on your specific condition. - Medication
- The specific medications that are used to support patients are directly related to the cause of the symptom or sign. Just as the symptoms of myocarditis mirror those of congestive heart failure, so too do the therapies. Additionally, the order in which therapies are used depends on the degree of heart dysfunction, with stabilization of patient blood pressure and breathing taking highest priority when present. 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 or Angiotensin Receptor Blockers (ARBs) can have a protective benefit to the heart, so either 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.
- Repurposable Drugs
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Repurposable drugs for myocarditis, a condition characterized by inflammation of the heart muscle, include:
1. **Colchicine:** Traditionally used for gout and pericarditis, it has anti-inflammatory effects that may benefit myocarditis.
2. **Corticosteroids (e.g., Prednisone):** These are used to reduce inflammation and immune response.
3. **IVIG (Intravenous Immunoglobulin):** Used in some autoimmune and inflammatory conditions to modulate the immune system.
4. **NSAIDs (Nonsteroidal Anti-Inflammatory Drugs):** Can alleviate pain and inflammation but are used cautiously due to potential side effects on the heart.
Management and treatment should always be under the guidance of a healthcare provider. - Metabolites
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Myocarditis is inflammation of the heart muscle and can alter various metabolites. Specific metabolomic changes include:
1. **Amino Acids**: Elevated levels of branched-chain amino acids (BCAAs) like leucine, isoleucine, and valine are often observed.
2. **Energy Metabolites**: Altered levels of metabolites involved in energy production, such as lactate, succinate, and pyruvate.
3. **Lipid Metabolites**: Changes in lipid metabolites, including free fatty acids, phospholipids, and sphingolipids, can occur.
4. **Oxidative Stress Markers**: Increased levels of markers like malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) indicate oxidative stress.
Metabolomic profiling can help in understanding the biochemical changes in myocarditis and may potentially aid in diagnosis and treatment. - Nutraceuticals
- There is limited evidence supporting the use of nutraceuticals for the treatment of myocarditis. Nutraceuticals like omega-3 fatty acids, Coenzyme Q10 (CoQ10), and some antioxidants have been explored for their potential cardiovascular benefits, but their efficacy in treating myocarditis specifically is not well-established. It's essential for individuals with myocarditis to seek medical advice and follow evidence-based treatments recommended by healthcare professionals.
- Peptides
- Myocarditis is an inflammation of the heart muscle. The role of peptides in myocarditis is a topic of ongoing research, as certain peptides may have potential therapeutic or diagnostic value. For example, antimicrobial peptides and other peptide-based modulators have been investigated for their anti-inflammatory properties and potential to reduce myocardial damage. The nan, or nanotechnology, approach is also under exploration for targeted drug delivery and improved imaging in myocarditis. Nanoparticles can be engineered to deliver therapeutic agents directly to inflamed heart tissue, potentially enhancing treatment efficacy and reducing side effects.