What are the early symptoms of myocarditis in children?

Now that the country has opened up the two-child policy, families with better living conditions will consider having a second child. One reason is to provide for future retirement, and the other is that one child would be too lonely and they would at least need a companion. In the process of children's growth, they will actually encounter many troubles, not just simple ones in daily life, but more serious ones are diseases. For example, do you know the early symptoms of viral myocarditis in children?

After children suffer from viral myocarditis, they will have symptoms such as poor spirits, pale complexion, and general fatigue, as well as nausea, vomiting, abdominal pain, fever and other symptoms. A small number of children with severe illnesses will have symptoms of cardiogenic shock such as increased heart rate, shortness of breath, enlarged liver and lungs, low blood pressure, and cold limbs.

1. There are prodromal symptoms such as upper respiratory tract infection, diarrhea, vomiting, abdominal pain, fever, etc. 1-3 weeks or several days before the onset of the disease.

2. The child is in poor spirits, pale, sweating all over the body, has discomfort or pain in the upper abdomen, and general fatigue.

3. When the symptoms are severe, there may be manifestations of heart failure such as edema, shortness of breath, and limited movement.

4. A few people may suffer from sudden heart failure, pulmonary edema, severe arrhythmia, cardiogenic shock, and cardio-cerebrovascular syndrome.

5. The heart size is normal or enlarged, the heart sounds are weakened, the first heart sound is low and dull, and there may even be fetal heart sounds or gallop rhythm.

6. The heart rate increases or decreases, and premature beats occur frequently.

7. In some cases, grade I-III systolic murmurs, pericardial friction sounds or pericardial effusion signs may be heard in the precordial area.

8. Severe cases may include signs of heart failure such as shortness of breath, cyanosis, moist rales in the lungs, hepatomegaly, edema, and symptoms of cardiogenic shock such as weak pulse, decreased blood pressure, skin patterns, and cold limbs.

Causes of viral myocarditis in children

It can be caused by a variety of viral infections, such as coxsackie B virus, echovirus, influenza virus, rotavirus, measles virus, mumps virus, adenovirus, varicella-zoster virus, Epstein-Barr virus, etc.

Viral myocarditis caused by group B viruses is the most common. The pathogenesis of this disease is not yet fully understood. It is currently believed that the direct invasion of the virus on the myocardium and the immune dysfunction caused by viral infection are the main pathogenesis of the disease.

Viruses can damage the heart in two ways: one is that after the virus enters the body, it reaches the heart with the blood flow and directly enters the myocardial cells, causing damage to the cells; the other is that after the virus enters the body, it induces the body itself to produce some substances that harm myocardial cells, causing damage to the myocardial cells.

After infection by Coxsackievirus, the spleen can be stimulated to produce reactive, cytolytic T lymphocytes. These cells have an autoimmune effect on myocardial cells that serve as antigens, and have a lytic effect on both infected and uninfected myocardial cells, causing extensive lesions and severe cell necrosis. They can also produce virus-specific cytolytic T lymphocytes. After viral infection, myocardial antigens that have been changed by the virus appear on the surface of myocardial cells. Since T lymphocytes can recognize this antigen, the infected myocardial cells dissolve and cause inflammation. The above two types of T cells are thymus-dependent T cells. After the thymus is removed, the above reactions will not occur even if the virus infects again.