viral myocarditis



OVERVIEW

Definition.

Viral myocarditis is a localized or diffuse inflammatory lesion of myocardial tissue based on viral infection.

Types

Types of viral myocarditis

Insidious type: viral myocarditis without conscious symptoms.

Sudden death type: the initial symptoms are hidden, with the progress of the disease may appear sudden death.

Arrhythmia type: viral myocarditis with arrhythmia as the main symptom.

Heart failure type: viral myocarditis characterized by heart enlargement, left, right or total heart failure.

Violent type: this type is characterized by a rapid onset and rapid deterioration, often with heart failure, cardiogenic shock, or severe arrhythmia within a few days of viral infection.

Chronic myocarditis: characterized by prolonged and repeated illnesses, with mild and severe symptoms that last for a longer period of time.

Stages of viral myocarditis

Acute stage: refers to viral myocarditis within 6 months of disease duration.

Recovery stage: refers to viral myocarditis with a disease duration of more than 6 months, but the condition has improved.

Chronic phase: viral myocarditis with a disease duration of more than 1 year and recurrent disease.

Morbidity

Incidence rate

At present, there is no authoritative data on the incidence of viral myocarditis in China.

Foreign research data show that the incidence rate of viral myocarditis in the group of acute viral infection is 1% to 5%.

Epidemic characteristics

Although viral myocarditis is not an infectious disease, it can be caused by viral infection, and viruses can cause outbreaks in a certain space and time range.

Although viral myocarditis is mostly disseminated, but there can also be outbreaks of epidemic.

Since the disease-causing virus is mostly prevalent in summer and fall, viral myocarditis is mostly seen in summer and fall.

Population distribution

Sex distribution: Men are more likely to develop viral myocarditis than women, but the difference is not significant.

Age distribution: Viral myocarditis is more common in preschool children and young adults.

Causes

Causative factors

Viral myocarditis is caused by viral infections, the most common of which are intestinal and upper respiratory tract infections. The following viral infections are the most common.

Coxsackievirus group B: The most predominant causative virus.

Echovirus.

Poliovirus.

Adenovirus.

Haplovirus B19.

Hepatitis C virus.

Herpes virus.

Influenza and parainfluenza viruses.

Viral myocarditis can occur throughout the year, but coxsackievirus infections tend to occur in the summer and influenza viruses tend to occur in the fall. Therefore, viral myocarditis is most often seen in summer and fall.

Pathogenesis

Virus directly damages cardiomyocytes

After virus infection through the upper respiratory tract or the intestinal tract, it can be absorbed into the blood circulation and then reach the cardiac muscle tissue through the blood circulation.

Viruses can replicate in large quantities in cardiomyocytes, causing viremia, which can directly cause damage to cardiomyocytes.

Viruses mediate the autoimmune system

Viruses can also mediate damage to the myocardium by the autoimmune system, mainly mediated by T lymphocytes.

This leads to persistent myocardial cell damage and the eventual development of chronic myocarditis or even dilated cardiomyopathy.

Symptoms

Symptoms of viral myocarditis depend on the extent and location of the lesions.

In mild cases, there may not be any symptoms; in symptomatic cases, it may manifest as weakness, palpitation, chest pain, etc. In a few severe cases, heart failure may occur, complicated by severe arrhythmia, etc., and in severe cases, it may lead to sudden death.

Main Symptoms

Pre-onset symptoms

One to three weeks before the onset of viral myocarditis, most people have had respiratory or digestive tract infections.

Symptoms include fever, generalized muscle pain, fatigue, sore throat, nausea and vomiting, and diarrhea.

Symptoms associated with myocarditis

Palpitations, a feeling of self-conscious discomfort or panic of the beating heart. When palpitations occur, the heart rate may be fast or slow, or there may be arrhythmia, and people with normal heart rate and rhythm may also have palpitations.

Chest tightness, manifested as conscious chest pressure, which may be accompanied by dyspnea in severe cases.

Pain in the anterior region of the heart, most of which is not severe.

Arrhythmia, which is characterized by irregular heartbeat, fast and slow or missed beats.

Other symptoms

Viral myocarditis may have the following symptoms, which are generally caused by the weakening of the contractile function of the heart and insufficient blood and oxygen supply to tissues and organs throughout the body.

Fatigue and weakness, manifested as mental depression.

Dizziness and blackout, associated with arrhythmia, cerebral ischemia and, in severe cases, syncope.

Loss of appetite and nausea may be related to insufficient blood supply to the gastrointestinal tract.

Complications

If treatment is not timely and standardized, viral myocarditis can induce complications such as cardiogenic shock, heart failure and dilated cardiomyopathy.

Cardiogenic shock

Cardiogenic shock refers to a group of syndromes in which the rapid decline in cardiac function leads to a significant reduction in cardiac output and causes severe acute peripheral circulatory failure.

In the early stage of shock, the main manifestations are palpitations, cold sweat all over the body, cold and wet extremities and fingers and toes, normal blood pressure or a slight drop; then there is apathy, blurred consciousness, weak pulse, oliguria or even anuria, etc. The blood pressure may decrease significantly. Blood pressure may be significantly reduced.

Cardiogenic shock has a relatively high case fatality rate of 70% to 100%.

Heart Failure

Heart failure is a condition in which the ventricular function decreases due to structural and/or functional diseases of the heart, resulting in an inability of the cardiac output to meet the demands of the body’s tissues and organs.

The main symptoms are palpitations, dyspnea, limitation of physical activity, coughing with copious amounts of pink foamy sputum, and lower extremity edema.

Dilated cardiomyopathy

Dilated cardiomyopathy is a cardiomyopathy characterized by enlargement of the left ventricle or both left and right ventricles, accompanied by systolic dysfunction.

Early stage can be asymptomatic due to the compensatory mechanism of cardiac function. Some patients with myocarditis may progress to dilated cardiomyopathy.

With the progression of the disease, it manifests as dyspnea and decreased activity tolerance during activities, paroxysmal nocturnal dyspnea and sedentary respiration may also occur, and symptoms such as decreased appetite, abdominal distension, nausea and vomiting, liver enlargement, and lower limb edema may gradually appear.

Consultation

Department of Medicine

Cardiovascular Medicine

Symptoms such as fever, joint pain, palpitation after exertion, shortness of breath, cough, etc. are recommended to consult a doctor promptly.

Emergency Department

If you experience sudden severe chest pain or difficulty in breathing, it is recommended that you go to the Emergency Department or call the 120 emergency number immediately.

Preparation for medical treatment

Preparation for medical consultation: registration, preparation of documents, common problems

Tips

Do not abuse drugs without the doctor’s permission, so that the drugs will not affect the relevant examinations and interfere with the diagnosis and treatment of the disease.

Preparation Checklist

Pay particular attention to the time of onset of symptoms, special performance, etc.

Do you have fever, sore throat, muscle aches and pains?

Are there palpitations, chest tightness, pain in the precordial area?

How long have the symptoms lasted?

Are there any other signs of discomfort?

Are you allergic to any medications or foods?

Any recent colds, gastroenteritis, hepatitis, etc.?

Are there any other medical conditions?

Test results from the last six months to bring to the doctor’s office

Routine blood tests.

Blood biochemistry.

Myocardial injury marker test.

Pathogenetic tests.

Echocardiogram.

Chest X-ray.

Cardiac magnetic resonance imaging.

Electrocardiogram and 24-hour ECG.

Medication use in the last 3 months, carry the box or package with you to the doctor if available

Glucocorticoids: dexamethasone, hydrocortisone.

Diuretics: furosemide, hydrochlorothiazide.

Cardiac stimulants: digoxin, digitalis.

Diagnosis

Disease diagnosis

Medical history

Recent (1 to 3 weeks) history of upper respiratory tract infectious disease.

Within the recent past (1 to 3 weeks), had an infectious disease of the intestinal tract.

Has viral hepatitis C or is a carrier of the hepatitis C virus.

Clinical manifestations

Fever, generalized muscle pain, sore throat, weakness, nausea, vomiting and diarrhea in the first stage.

With the progression of the disease, symptoms such as increased heart rate, chest tightness, vague pain in the chest area, and fatigue appear.

The heart size increases.

The heart rate may increase or slow down; the heart is found to be irregular, or beating prematurely; abnormal heart sounds may be heard.

Laboratory Tests.

May help the doctor determine if an infection is present and are helpful in determining if bacterial endocarditis or a concomitant infection is present.

Can help differentiate whether the infection is viral or not, and can give indirect feedback on the effectiveness of treatment.

To find out about changes in troponin, etc.

Can help doctors determine the extent of myocardial damage and can also differentiate from diseases such as myocardial infarction.

If virus-specific antibody test, it helps to diagnose the cause of the disease.

Imaging

Echocardiography is a non-invasive test that shows the anatomy, size and functional status of the heart and large blood vessels.

Precautions

It can observe whether the heart shadow is enlarged or not, and then determine whether there is any change in the volume of the heart.

Precautions

Magnetic resonance imaging of the heart is characteristic of viral myocarditis and can assist the physician in diagnosis.

Precautions

In viral myocarditis, the myocardium is damaged, resulting in a decreased ability to take up nuclides. Therefore, myocardial perfusion imaging using methyl isonitrile analogs (99mTc-MIBI) can show the site of myocardial damage.

Precautions: Remove jewelry or metal objects from the examination area before the examination; stay away from people as much as possible after the examination.

Electrocardiogram

Abnormal changes may occur in viral myocarditis.

Precautions

Endomyocardial pathology

Endocardial myocardial biopsy can confirm the diagnosis of viral myocarditis, but because of its invasive nature, it is generally not used as a routine examination, and is only used for those with acute and serious conditions or whose etiology is unknown.

Differential diagnosis

Pericarditis

Similarities: Both may present with symptoms such as chest tightness, chest pain, and weakness.

Differences: Pericarditis pain can radiate to the neck, left shoulder, left arm, and also up to the epigastric region. The pain is sharp in nature, associated with respiratory movements, and is often aggravated by coughing, deep breathing, changing position, or swallowing. With the development of the disease, the symptoms may change from chest pain in the fibrinoid phase to dyspnea in the exudative phase, and some patients may suffer from cardiac tamponade due to moderate or large amount of pericardial effusion, which may lead to a series of related symptoms such as dyspnea and edema. Differential diagnosis can be made by questioning.

Kawasaki disease

Similarities: Kawasaki disease is common in preschool children, with symptoms such as fever and malaise in the early stage, and chest pain and dyspnea as the disease progresses.

Differences: Kawasaki disease is characterized by prominent coronary artery lesions, while viral myocarditis mainly affects the myocardium, manifesting symptoms such as arrhythmia, heart enlargement and heart failure. Kawasaki disease is usually preceded by high fever and accompanied by symptoms such as strawberry tongue, while viral myocarditis has symptoms such as sore throat, generalized muscle pain and diarrhea. It can be differentiated by clinical symptoms and physical examination.

Endocarditis

Similarity: Fever and malaise may occur in both cases.

Differences: 80% of patients with endocarditis have circulating immune complexes, and 50% of patients with more than 6 weeks of disease are positive for rheumatoid factor; endocarditis is usually accompanied by redundant organisms, perivalvular complications, etc. Therefore, it can be differentiated by immunologic examination and physical examination. Therefore, it can be differentiated by immunologic examination and echocardiography.

Treatment

General treatment

The general treatment of viral myocarditis consists of rest and diet aimed at reducing the cardiac load and preventing heart failure and cardiac enlargement.

Rest

Bed rest is recommended to prevent overexertion.

The duration of bed rest should be in accordance with the doctor’s instructions, and the patient should not get out of bed until the symptoms have disappeared. Generally, bed rest is required for 3 to 4 weeks in the acute stage, and 3 months for those with cardiac insufficiency.

Strenuous exercise and overexertion should not be allowed even after the symptoms have disappeared, and should still be restricted for a period of time.

Diet

Eat small and frequent meals to avoid consuming a large amount of food at one time, which will aggravate the burden on the heart.

If heart failure has already occurred, water and salt intake need to be restricted, the specific method of restriction and the amount that can be consumed should follow the doctor’s instruction.

It is recommended to eat more foods rich in water-soluble dietary fiber to prevent constipation, such as cabbage, radish, mushrooms, seaweed and sweet potato.

Medication

There are no specific drugs for viral myocarditis, but the following drugs can be used to control symptoms and improve myocardial function. Increase myocardial nutrition to improve myocardial metabolism: commonly used drugs include high-dose vitamin C, 1,6-bisphosphate fructose, sodium phosphocreatine, pan-decanolone (coenzyme Q10) and so on.

Anti heart failure treatment: digitalis drugs can be used, such as digoxin or furfuracin propyl; circulatory system congestion can be appropriate application of diuretics; reduced cardiac output can be applied to vasoactive drugs such as dopamine.

Arrhythmia control: digoxin can be used for supraventricular tachyarrhythmia; lidocaine can be used for ventricular tachyarrhythmia.

Immunomodulators: intravenous immunoglobulin, hormones and other immunosuppressants.

Glucocorticoids: glucocorticoids such as dexamethasone and hydrocortisone may be used when other medications are not effective.

Other treatments

Pacemaker

A pacemaker is a medical device that mimics the electrical activity of the heart, replacing the heart’s electrical signals with artificial electrical stimulation, thus ensuring a normal heartbeat and maintaining systemic organ function.

It is suitable for viral myocarditis complicated by severe arrhythmia.

Ventilator

A machine that replaces voluntary respiration, ensures oxygen demand, improves ventilation, and expels carbon dioxide at the same time.

Suitable for patients with respiratory failure.

Prognosis

Cure

Viral myocarditis can be cured, but some viral myocarditis may leave complications.

Harmfulness

Affects normal life

Symptoms caused by viral myocarditis can make people feel uncomfortable and affect the state of work, study and life.

Viral myocarditis requires bed rest and avoiding exertion, which can affect normal work and life.

Causes complications

Viral myocarditis may induce serious complications such as cardiogenic shock, heart failure and dilated cardiomyopathy in severe cases. In severe cases, it may lead to sudden death or congestive heart failure and death.

Daily

Daily Management

Dietary management

Eat small and frequent meals, and each meal should not be too full.

The principle of diet is light and easy to digest. More green vegetables and fresh fruits can be eaten to prevent constipation; at the same time, sufficient amount of high quality protein should be consumed.

If combined with heart failure, also need to reduce the input of salt, avoid eating pickled and processed food.

Avoid drinks such as coffee and strong tea. Abstain from alcohol.

Food and water must be clean to prevent intestinal infections.

Lifestyle management

Take more bed rest and ensure sufficient sleep.

Avoid excessive stress and relax.

Pay attention to increase or decrease clothing according to the season to prevent upper respiratory tract infectious diseases.

Exercise appropriately and enhance physical fitness as long as cardiac function permits.

Quit smoking.

Emotion management

Positively adjust the bad mood and keep a good mindset.

Disease monitoring

Monitor blood pressure and heart rate daily and record them. More obvious fluctuations require prompt medical attention.

Follow-up

Follow the doctor’s instructions for regular follow-up.

If you experience rapid heartbeat, chest tightness, dizziness and blackouts, it is recommended that you consult a doctor promptly.

Prevention

Prevent infection, avoid going to crowded places during the period of high incidence of viral infection, or go to the hospital to get vaccinated, and go to the hospital in time if you have any symptoms.

Strengthen the body, reasonable exercise, improve the body’s immunity.

Eat a reasonable diet, eat more vegetables and fruits, eat less fried, spicy food.

Regular work and rest, usually do not stay up late, to ensure adequate sleep.

Good attitude, learn to regulate emotions, keep optimistic and positive attitude.