Myocarditis: Symptoms, Treatment, Clinical Guidelines

2024 Author: Rachel Wainwright | [email protected]. Last modified: 2024-01-15 19:51

Myocarditis

The content of the article:

1. Causes
2. Forms of the disease
3. Disease stages

4. Myocarditis symptoms

   Heart failure

5. Diagnostics

   Diagnostic criteria

6. Myocarditis treatment

   Myocarditis: clinical guidelines

7. Forecast
8. Prevention
9. Video

Myocarditis is an inflammation of the heart muscle (myocardium) caused by infectious, infectious-toxic or infectious-allergic causes. Inflammation of myocytes (myocardial cells) leads to their necrosis or degeneration, which causes heart failure and arrhythmic disorders. Heart failure can be rapid and severe, even fatal.

Myocarditis is common at a young age

Men suffer from myocarditis more often than women, the ratio of men to women is estimated at 1.5: 1. The average age of patients is 42-45 years old, adults are characterized by a subacute form of the disease, while children, especially newborns, are fulminant (fulminant). In addition, the fulminant form occurs in weakened, immunocompromised individuals and pregnant women.

Causes

Often, myocarditis occurs in people without obvious health problems, and the cause cannot be established.

Possible causes of myocarditis are divided into three groups:

Causal factor	Description
Infection	Viruses: parvovirus B19 (the most common cause of acute myocarditis, leading to acute heart failure with ST segment elevation), herpesvirus type 6, Coxsackie virus type B, adenoviruses. Bacteria: Mycobacterium tuberculosis (the causative agent of tuberculosis), Borrelia burgdorferi (the causative agent of Lyme disease), Haemophilus influenza (the causative agent of hemophilic infection), Salmonella spp. (causative agents of salmonellosis, typhoid, paratyphoid fever), Legionella spp. (causative agent of legionellosis), Corynebacterium diphtheriae (causative agent of diphtheria), Streptococcus pyogenes (causative agent of scarlet fever), etc. Fungi, such as the yeast-like fungi of the genus Candida. Protozoa: Entamoeba histolytica, Toxoplasma gondii. Helminths such as Trichinella spiralis.
Autoimmune and allergic processes	Autoimmune diseases (systemic lupus erythematosus), autoimmune reactions caused by organ transplantation, post-vaccination reaction, bronchial asthma.
Intoxication	Some drugs (anti-tuberculosis, antiepileptic, non-steroidal anti-inflammatory, diuretics, methyldopa, clozapine, amitriptyline), heavy metal salts, cocaine, snake venom.

Forms of the disease

Myocarditis happens:

• primary - arises as an independent isolated pathological process (idiopathic myocarditis of Abramov - Fiedler);
• secondary - in this case, myocarditis acts as one of the symptoms of another, general disease.

Secondary myocarditis, depending on the cause that caused it, has the following forms:

• rheumatic - associated with autoimmune pathology;
• infectious - associated with a bacterial, viral or fungal infection (also infectious-allergic, often caused by foci of infection in the tonsils, paranasal sinuses, teeth);
• allergic - serum, medicinal, post-vaccination, caused by bronchial asthma;
• myocarditis caused by trauma (extensive burns, exposure to ionizing radiation, polytrauma).

Depending on the course, myocarditis is distinguished:

1. Fulminant. Has a sudden onset with pronounced symptoms, with rapidly progressive heart failure, up to the development of cardiogenic shock; however, it often resolves spontaneously and safely, although in rare cases it can be fatal.
2. Acute. It begins less pronounced in comparison with fulminant, heart failure grows, although less rapidly, but rather quickly. In some patients, left ventricular myocardial dysfunction transforms into dilated cardiomyopathy.
3. Subacute or chronic. It is active and persistent. Chronically active occurs with frequent relapses, characterized by increased myocardial fibrosis. Chronically persistent does not lead to dilatation of the left ventricle, but it is characterized by severe and prolonged pain syndrome.

The most common classification of myocarditis is Dallas - by the name of the American city in which it was adopted in 1986. The disease is classified in four areas:

Classified feature	Forms of myocarditis
Degree of inflammation	· Light; · Moderate; · Heavy.
The prevalence of inflammation	· Focal (focal); · Merging; · Diffuse.
Fibrosis	· Usual; · Increased.
Type of inflammatory infiltrate	· Eosinophilic; · Neutrophilic; · Giant cell; Lymphocytic; · Mixed.

Disease stages

Since the most common cause of myocarditis is a viral infection, the stages of the disease are determined specifically for this form.

1. Viremia stage. It starts from the moment the virus enters the body, lasts from several hours to several days, during which the virus enters the myocardium with blood flow, first accumulating on the surface of myocytes, and then penetrating into the cells. This triggers a powerful immune response, due to which the virus is removed from the myocardium within 10-14 days, although it can be detected in the blood for up to three months. In most cases, this disease is safely resolved. If this does not happen, the second stage begins.
2. The stage develops with an inadequate immune response on days 5-6, characterized by an increased content of antibodies, which further damage the myocardium (foci of hypoxia and necrosis are formed). Heart failure is forming and growing.
3. The stage of recovery in a favorable case. Areas of necrosis are replaced by fibrous tissue, inflammatory edema and cellular infiltration are reduced, and cardiac function is restored. In an unfavorable case, this is a stage in the development of a chronic process, which is characterized by the appearance of cardiomegaly (enlargement of the heart), cardiosclerosis, and further progression of heart failure.

Myocarditis symptoms

Often (in 70-80% of cases) the disease proceeds in a subclinical form, that is, it is mild. In this case, symptoms are limited to general mild to moderate malaise, fatigue, weakness, dizziness (especially characteristic of infectious myocarditis), mild shortness of breath and muscle pain.

In a small number of cases, pronounced symptoms develop due to massive inflammation of the myocardium, with fulminant congestive heart failure.

The clinical picture of myocarditis can include several syndromes, depending on the severity and form of the disease.

Syndrome	Description
Flu-like syndrome	It is observed in about half of the patients. Often preceded by a detailed clinic of heart failure, but can also accompany it. It is characterized by respiratory symptoms, fever (usually not higher than 38 ° C), headaches, muscle and joint pain.
Chest pain	Localized on the left side of the chest. At the beginning of the disease, minor and short-term, then become moderately pronounced and constant (less often paroxysmal). The character is pressing or stabbing, dependence on physical or psycho-emotional stress or the time of day is not traced, however, the pain intensifies when raising the left arm and with a deep breath.
Dyspnea	It occurs during physical exertion, even a slight one, and in severe cases even at rest. Focal forms of myocarditis can occur without it.
Increased heart rate, abnormal heart rhythms	Observed in 40-50% of cases. Usually appear during physical or psycho-emotional stress, but in severe cases, they can occur at rest. Cardiac arrhythmias, paroxysmal tachycardia, bradycardia, syncope (an unfavorable sign that can be a harbinger of sudden death due to atrioventricular blockade) may occur.

Blood pressure is usually normal, but in some cases it can drop.

Different forms of myocarditis are distinguished by their inherent features:

1. Acute: History of recent viral infection, may mimic acute coronary syndrome.
2. Acute rheumatic fever: polyarthralgia, chorea, marginal erythema, the presence of subcutaneous nodules on the background of heart failure.
3. Eosinophilic: exanthema (macular-papular rash, accompanied by itching), sometimes eosinophilia in the peripheral blood. A history of the use of certain medications. In the most severe form (acute necrotizing eosinophilic myocarditis), acute heart failure develops with a fulminant course.
4. Giant cell: manifests itself as symptoms of progressive heart failure, prolonged ventricular tachycardia, less often ventricular arrhythmias or blockade predominate.
5. Sarcoid: arrhythmia, lymphadenopathy, sarcoid organ infiltration.
6. Cardiomyopathy of pregnancy: heart failure occurs at the end of gestation, or in the period 4-5 months after delivery.

Heart failure

Heart failure is a life-threatening condition and therefore requires special attention.

Signs of acute heart failure are:

• cardiac edema (symmetrical, arising on the limbs);
• tachycardia, galloping heart rhythm;
• mitral regurgitation;
• the appearance of heart murmurs from pericardial friction (with the addition of pericarditis).

Subacute heart failure:

• severe shortness of breath;
• cyanosis of the nasolabial triangle;
• increased body temperature;
• decreased appetite, sweating while eating;
• bradycardia.

Diagnostics

The possibility of acute myocarditis should be considered in young people with sudden onset of signs of heart failure, persistent heart rhythm and / or conduction disturbances, signs of myocardial infarction in the absence of changes in coronary angiography. In patients with heart failure with an indistinct onset, other possible causes of dilated cardiomyopathy should be ruled out.

The main diagnostic methods used when myocarditis is suspected:

1. Laboratory blood tests. In 70% of patients, an increased ESR is found, in 50% - neutrophilic leukocytosis; with systemic vasculitis and myocarditis of parasitic origin - eosinophilia. Increased levels of creatine phosphate kinase (CPK) and cardiac troponins. In patients with acute, fulminant myocarditis or with a sudden deterioration, CPK activity is increased.
2. ECG (electrocardiography). Supraventricular and ventricular arrhythmias, changes in the ST segment and the T wave in many leads, disturbances in intraventricular and atrioventricular conduction are found, the Q wave can be changed.
3. ECHO-KG (echocardiography). With fulminant myocarditis, diastolic volumes are within normal limits, a significant generalized violation of contraction and thickening of the left ventricular wall, with the development of heart failure, a picture of dilated cardiomyopathy is found.
4. MRI (magnetic resonance imaging). Edema and late enhancement on MRI with gadolinium.
5. Endomyocardial biopsy. It is indicated for advanced heart failure, recurrent ventricular tachycardia or ventricular fibrillation. Necessarily carried out with a fulminant course of the disease. Allows you to identify specific forms of myocarditis (eosinophilic, giant cell). When carrying out PCR (polymerase chain reaction) of myocardial cells, a positive result indicates in favor of viral myocarditis, a negative result - autoimmune (can be confirmed by anticardial autoantibodies in the blood serum).

Diagnostic criteria

In 2013, the European Community of Cardiology developed clinical diagnostic criteria for myocarditis.

	Criterion	Decoding
	Symptoms	a) Acute chest pain of a pericardial or ischemic nature; b) acute (up to 3 months) or progressive shortness of breath at rest or during exercise and / or fatigue; c) subacute or chronic (more than 3 months) shortness of breath at rest or on exertion and / or fatigue; d) palpitations and / or arrhythmias of unknown etiology and / or syncope and / or sudden arrest of blood circulation; e) cardiogenic shock of unknown etiology.
	Research results	a) New ECG changes - atrioventricular block or bundle branch block, ST segment elevation, T wave inversion, sinus block, ventricular tachycardia, ventricular fibrillation, asystole, atrial fibrillation, decreased R amplitude, slowed ventricular conduction (QRS expansion) Q wave, low voltage of teeth, extrasystole, supraventricular tachycardia; b) an increase in the level of cardiospecific markers (TnT, TnI); c) functional or structural changes during visualization (ECHO-KG, MRI, angiography) - new, not identified by other methods, changes in the function and structure of the left and / or right ventricle, including those that have no clinical manifestations and were discovered by chance; d) MRI reveals edema or a characteristic picture of late intensification (with MRI with gadolinium).

Myocarditis should be suspected if ≥ 1 clinical sign (1 a – d) and ≥ 1 characteristic test result are observed, provided that other cardiac pathology and diseases that can cause similar manifestations (heart defects, hyperthyroidism) are excluded. The more criteria are confirmed, the more reasonable the suspicion is. In asymptomatic patients (no criteria 1 a – d), myocarditis can be assumed if there are ≥ 2 deviations in the study results (different groups 2 a – d).

Myocarditis treatment

Etiotropic treatment is prescribed based on the cause of the disease:

• cancellation of causative drugs (with myocarditis of medicinal origin);
• antimicrobial therapy (if the cause is infectious);
• immunosuppressive therapy (with autoimmune, giant cell myocarditis, sarcoidosis).

Symptomatic treatment consists of maintaining heart function, eliminating pain, arrhythmia. Standard treatment for heart failure is provided.

With fulminant myocarditis, strict bed rest, extracorporeal membrane oxygenation, mechanical support of blood circulation are shown. Treatment is carried out in a specialized hospital.

Treatment of fulminant myocarditis is carried out in a specialized hospital

In severe cases, if other methods are ineffective, heart transplantation may be considered.

Myocarditis: clinical guidelines

1. Restriction of physical activity, especially for fever and other common symptoms of infection or heart failure.
2. Limiting the use of stimulants (strong coffee, tea, caffeinated drinks), avoiding alcohol.
3. Refusal to take drugs of the NSAID group (non-steroidal anti-inflammatory drugs), as they can aggravate the symptoms of myocarditis, especially viral.

Forecast

Most patients with acute and fulminant myocarditis recover. Some patients develop dilated cardiomyopathy. The prognosis worsens with a subacute course of the disease.

Prevention

Prevention of myocarditis is adequate treatment of those diseases that can lead to it.

Video

We offer for viewing a video on the topic of the article.

Anna Kozlova Medical journalist About the author

Education: Rostov State Medical University, specialty "General Medicine".

The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!