myocarditis
Introduction
Introduction to myocarditis Myocarditis refers to localized or diffuse inflammation of the myocardium caused by various causes, although some myocarditis may be regarded as secondary in some scholars due to transition to congestive or restrictive cardiomyopathy at the end stage. Cardiomyopathy, but in the pathogenesis, myocarditis is a distinguishable type of disease. There are many causes of myocarditis. Viruses, bacteria, fungi, parasites, immune reactions, and physical and chemical factors can cause myocarditis. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: arrhythmia acute heart failure cardiogenic shock
Cause
Cause of myocarditis
The causes of myocarditis can be divided into the following categories:
Infectious factors (25%):
Viruses such as Coxsackie virus, Echo virus, influenza virus, adenovirus, hepatitis virus, etc.; bacteria such as diphtheria, streptococcus, etc.; fungi; rickettsia; spirochetes; protozoa. Among them, viral myocarditis is the most common, and myocardial localized or diffuse acute or chronic inflammatory lesions caused by viral infection are infectious myocardial diseases.
Autoimmune disease (20%):
It refers to the disease caused by the body's immune response to its own antigen, which causes damage to its own tissues. For example, systemic lupus erythematosus and giant cell myocarditis, most of the reasons are unknown, may be related to genetics, infection, drugs and the environment.
Physical factors (15%):
Such as myocardial damage caused by radiotherapy of the chest.
Chemical factors (10%):
Such as a variety of drugs such as some antibiotics, tumor chemotherapy drugs.
Prevention
Myocarditis prevention
Strengthen physical exercise, improve the body's ability to resist disease, avoid fatigue to prevent viruses, bacterial infections, pay attention to rest after the onset, enter a nutrient-rich diet to facilitate heart recovery.
To prevent myocarditis in spring: In recent years, due to the widespread use of antibiotics, the rheumatic fever caused by streptococcal infection has gradually decreased, the incidence of rheumatic myocarditis has decreased significantly, and the incidence of viral myocarditis has increased. Viral myocarditis can be caused by various viral infections. Among them, Coxsackie B virus is the most common, chickenpox and EB virus can also be caused. According to the study, about 5% of infected people can affect myocarditis in the heart after infection, which can directly affect the myocardium after viral infection. It is caused by autoimmune reaction after viral infection. The former is more common in children, the latter is more common in adolescents, and spring is a high season of viral myocarditis, which should cause people to be vigilant.
Complication
Myocarditis complications Complications arrhythmia acute heart failure cardiogenic shock
Most patients recover after appropriate treatment without leaving any symptoms or signs. Very few patients die in the acute phase due to severe arrhythmia, acute heart failure and cardiogenic shock, and some patients become pregnant after weeks or months. Stable, but with a certain degree of heart enlargement, cardiac dysfunction, arrhythmia or ECG changes, this situation has remained unchanged for a long time, roughly after the acute phase of myocardial scar formation, becoming a sequelae, and some patients continue to have inflammation after the acute phase, Switching to chronic myocarditis, progressive progressive heart enlargement, cardiac dysfunction, arrhythmia, after several years or one or twenty years later died of the above complications, the time division of each stage is more difficult, generally 6 months The acute phase is internal, the recovery period is from June to 1 year, and the chronic phase is more than one year. Chronic patients with unclear acute phase are difficult to distinguish from cardiomyopathy. According to current knowledge and evidence, some cardiomyopathy is evolved by myocarditis. Come.
Symptom
Symptoms of Myocardial Inflammatory Symptoms Symptoms of palpitations with fatigue, pale palpitations, abnormal heart rate, fatigue, young women, palpitations, chest tightness, job burnout, arrhythmia, muscle soreness, rapid heart rate, heart rate, palpitations, diarrhea, atrial contraction
Young adults have more onset, often with primary infections. For example, viral people often have fever, sore throat, cough, vomiting, diarrhea, muscle soreness, etc. Most of the symptoms of myocarditis occur after 1-3 weeks of viral infection. Because of arrhythmia, heart palpitations can be weak due to decreased blood output. When the pericardium and pleura are involved, chest tightness, chest pain, and similar angina pectoris, severe cardiac insufficiency, common signs, sinus tachycardia Parallel to body temperature, there may be sinus bradycardia and various arrhythmias, and the heart-bound enlargement accounts for 1/3-1/2. Seen in severe myocarditis, the mitral or tricuspid valve can be closed due to enlarged heart. Incomplete, systolic murmur in the apex of the apex or the lower left sternum, severe myocardial damage or heart failure, can be heard in the diastolic period, the first heart sound is weakened, and those with pericarditis can hear the pericardial friction sound.
Light can be completely asymptomatic, severe heart failure or sudden death, disparity, according to clinical manifestations can be divided into six types:
1, asymptomatic: S-T changes in the electrocardiogram 1-4 weeks after infection, asymptomatic;
2, arrhythmia type: showing various types of arrhythmia, ventricular premature contraction is most common;
3, heart failure type: the symptoms and signs of heart failure;
4, myocardial necrosis: clinical manifestations similar to myocardial infarction;
5, heart enlargement: heart enlargement, systolic murmur in the mitral and tricuspid valve;
6, sudden death type: no aura, sudden death.
Examine
Myocarditis examination
1. Electrocardiogram: The positive rate of abnormal electrocardiogram is high, and it is an important basis for diagnosis. After the onset, the electrocardiogram can suddenly become abnormal and disappear with the regression of infection. The main performance is ST segment down, T wave low or Inverted.
2, X-ray examination: due to the extent of the lesion and the severity of the lesion, the radiation examination is also quite different, about 1/3-1/2 of the heart is enlarged, mostly mild to moderate enlargement, and the enlarged enlargement is often accompanied by pericardial effusion The heart shadow is spherical or flask-shaped, the heart beat is weakened, localized myocarditis or mild lesions, the heart can be completely normal.
3, blood test: white blood cell count in viral myocarditis can be normal, high or decreased, erythrocyte sedimentation rate is mostly normal, but also slightly increased, C-reactive protein is mostly normal, GOT, GPT, LDH, CPK normal or elevated, chronic myocarditis In the normal range.
4, conditional can do virus isolation or antibody determination.
Diagnosis
Diagnosis and diagnosis of myocarditis
diagnosis
Diagnosis can be based on the cause, clinical symptoms and related tests.
Differential diagnosis
1. Primary endocardial fibroelastosis
The similarity is that the heart is enlarged, heart failure occurs repeatedly, and cardiogenic shock can be seen, but the disease mostly occurs in small infants under 6 months. The endocardial elastic fiber hyperplasia and myocardial degeneration affect the whole heart, electrocardiogram and Echocardiography showed mainly left ventricular hypertrophy, clinical manifestations of recurrent left heart failure symptoms, cardiac hypertrophy, heart sounds weakened, no murmur or mild systolic murmur, no history or symptoms of viral infection, no virus Laboratory tests for myocarditis have changed.
2, toxic myocarditis
Have a history of serious infection or drug poisoning, often complicated by severe pneumonia, typhoid fever, sepsis, diphtheria, scarlet fever and other diseases, often with the improvement of the symptoms of the primary disease and gradually recover, using ipecaine, expectorant, etc. can cause myocarditis, with The drug is reduced or deactivated and gradually improved or recovered.
3, rheumatic carditis
Have a history of recurrent respiratory infections, symptoms of rheumatism such as high fever, multiple migratory arthritis, ring erythema and subcutaneous nodules, mitral systolic and/or diastolic murmurs in valvular lesions, laboratory examination Evidence of increased ESR, positive C-reactive protein, increased mucin and anti-hemolytic streptococcus "O", increased streptococcal kinase titer and positive for throat swab culture.
4, Keshan disease
Similarities are heart enlargement, heart rhythm disorder, heart failure or cardiogenic shock, but Keshan disease is endemic, often in a prevalent area, with multiple seasons (such as northeastern winter and spring, southwestern summer is more) and age. Object points (such as young women in Northeast China, children aged 2-5 years in the southwest), ST-T changes on the electrocardiogram, right bundle branch block, low voltage is more common; arrhythmia rhythm is variable, fast change, heart rate is obvious Increased or slowed down, X-ray examination of the heart enlargement is significant, pulsation is significantly weakened, can not retract to normal after control of heart failure, most of the chronic phase becomes chronic after the acute phase, sometimes due to the heart in the heart of the thrombus Embolism, convulsions or hemiplegia.
