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Cardiotropic virus infection

Introduction
Cause
Examine
Diagnosis

Introduction

Introduction Viral myocarditis refers to the infection of a human heart with a corticovirus that causes non-specific interstitial inflammation of the myocardium. It may be localized or diffuse; the course of the disease may be acute, subacute or chronic. Most patients with acute viral myocarditis can return to normal, with few sudden deaths, and some chronically developed viral myocarditis can evolve into cardiomyopathy. Some patients have sequelae after myocardial scar formation: a certain degree of heart enlargement, cardiac dysfunction, arrhythmia or persistent abnormal ECG.

Cause

Cause

Various viruses can cause myocarditis, and the most common virus infection is the infection of the committee that causes intestinal and upper respiratory tract infections. The enterovirus is a picornavirus, in which Coxsackie, Echo (ECHO), and poliovirus are the main viruses causing myocarditis; it is not uncommon to see myocarditis caused by vitic viruses such as influenza, parainfluenza, and respiratory syncytial virus. Adenovirus also causes myocarditis. In addition, measles, mumps, Japanese encephalitis, hepatitis, cytomegalovirus, etc. can also cause myocarditis.

Examine

an examination

Related inspection

Enzyme-linked immunosorbent assay specific IgE antibody scanning electron microscope

The diagnosis of viral myocarditis must be based on evidence of myocarditis and evidence of viral infection. Chest tightness and palpitations can often indicate heart attack, heart enlargement, arrhythmia or heart failure as a manifestation of significant impairment of the heart. ST-T changes and ectopic rhythm or conduction disorders on the electrocardiogram reflect the presence of myocardial lesions. The evidence for viral infection has the following points:

1 There are fever, diarrhea or flu symptoms, and heart symptoms or ECG changes occur shortly after the onset.

2 serum virus neutralizing antibody determination positive results, because Coxsackie B virus is the most common, usually detect the neutralizing antibody of this group of viruses, take blood samples once in the early stage of onset and 2 to 4 weeks, such as secondary antibody titer A 4-fold rise or one of 1:640 can be used as a basis for recent infection with the virus.

3 pharyngeal and anal swab virus isolation, such as positive for auxiliary significance, some normal people can also be positive, the significance must be combined with the results of positive neutralizing antibody assay.

4 Detection of viral RNA from feces, serum or myocardial tissue by polymerase chain reaction.

5 myocardial biopsy: from the obtained living tissue for virus detection, virological examination is helpful for the diagnosis of myocarditis.

Diagnosis

Differential diagnosis

(1) Rheumatic heart disease

Cardiomyopathy may also have systolic murmurs in the mitral or tricuspid valve area, but generally do not have diastolic murmurs, and are louder in heart failure, and reduce or disappear after heart failure control, as opposed to rheumatic heart disease. Cardiomyopathy often has multiple heart chambers that expand at the same time. It is better for rheumatic heart disease than left atrium, left ventricle or right ventricle. Ultrasound is helpful to distinguish.

(2) pericardial effusion

In cardiomyopathy, the heart expands and the heart beats weakened, which must be distinguished from pericardial effusion. In cardiomyopathy, the apical beat shifts to the lower left, which is consistent with the left outer edge of the heart sounding boundary. The apical beat is often not obvious or is located inside the left outer edge of the heart sounding boundary. Mitral or tricuspid systolic murmur, ventricular hypertrophy on the electrocardiogram, abnormal Q wave, various complex arrhythmias, all indicate cardiomyopathy. Ultrasound examination is not difficult to distinguish the two, a large number of liquid flat or dark areas in the pericardium indicate pericardial effusion, and heart enlargement is cardiomyopathy. It must be noted that there may be a small amount of pericardial effusion during cardiomyopathy, but it is not enough to cause cardiac tamponade, nor does it affect the signs and heart function of the heart. It is only the discovery of ultrasound. The contraction time interval is obviously abnormal in cardiomyopathy, and the pericardial disease is normal.

(3) Hypertensive heart disease

Cardiomyopathy may have transient hypertension, but the diastolic blood pressure does not exceed 14.67 kPa (110 mmHg), and in acute heart failure, the blood pressure decreases after the heart failure improves. Unlike hypertensive heart disease, the fundus, urine, and kidney function are normal.

(4) coronary heart disease

Patients with middle-aged or older, if there is heart enlargement, arrhythmia or heart failure, and other reasons, coronary heart disease and cardiomyopathy must be considered. There are prone factors such as hypertension, hyperlipidemia or diabetes, and segmental abnormalities in the wall activity are conducive to the diagnosis of coronary heart disease. In recent years, coronary artery lesions cause long-term extensive ischemia and fibrosis of the heart, and the development of cardiac insufficiency is called "ischemic cardiomyopathy". If there is no angina or myocardial infarction in the past, it is difficult to distinguish it from cardiomyopathy. In addition, cardiomyopathy can also have pathological Q waves and angina pectoris. At this time, the identification must be based on coronary angiography.

(5) Congenital heart disease

Most have obvious signs and it is not difficult to distinguish. Tricuspid valvular malformation has tricuspid murmur, and may have galloping, heartbeat weakening, right heart enlargement and failure, must be different from cardiomyopathy, but the symptoms of this disease appear in early years, the left ventricle is not large, purpura With. Echocardiography can confirm the diagnosis.

(6) Secondary cardiomyopathy

Systemic diseases such as systemic lupus erythematosus, scleroderma, hemochromatosis, amyloidosis, glycogen accumulation, and neuromuscular diseases all have their primary manifestations. More important is the distinction between myocarditis. Acute myocarditis often occurs at the time of viral infection or soon after, and the difference is not very difficult. Chronic myocarditis, if there is no clear history of acute myocarditis, is difficult to distinguish from cardiomyopathy. In fact, many dilated cardiomyopathy develop from myocarditis, the so-called "myocardial post-myocardial disease."

In recent years, endocardial myocardial biopsy has been performed clinically. Specimens obtained from cardiac catheters with biopsy forceps for pathological and viral examinations can be used to find evidence of myocardial inflammation, but the current diagnostic criteria for histopathology and There are still some problems to be solved in removing artifacts.