Overview of viral pericarditis
Viral pericarditis (viral periearditis) is an inflammatory lesion of the pericardium caused by various viral infections. After viral infection of the pericardium, pericardial mucosal epithelial cells become swollen, degenerated, fibrous tissue proliferation, inflammatory exudation, and to a certain extent, cardiac function can be affected. People with pre-existing connective tissue disease or allergies are more likely to develop viral pericarditis. If treatment is not timely, it can be transformed into chronic viral pericarditis, which can eventually lead to complications such as constrictive pericarditis, pericardial tamponade and myocardial infarction.
Causes
There are various viruses that can cause pericarditis, the more common ones are enterovirus, orthomyxovirus and paramyxovirus. The more common viruses are coxsackieviruses group A and B, echoviruses, influenza viruses and parainfluenza viruses. The main source of infection is virus-infected persons or virus carriers, mainly through the respiratory tract and fecal-oral transmission. In addition to respiratory transmission, children are more susceptible to gastrointestinal transmission. Especially the susceptible people with low immunity are more likely to be infected with the virus and cause viral pericarditis.
Symptoms
Viral pericarditis can be categorized into acute, subacute and chronic pericarditis according to the duration of the disease. Acute viral pericarditis occurs when the duration of the disease is shorter than 6 weeks; subacute viral pericarditis occurs when the duration of the disease is between 6 weeks and 6 months; and chronic viral pericarditis occurs when the duration of the disease is longer than 6 months.
Viral pericarditis occurs most often in adolescents, and 1-2 weeks before the onset of pericarditis, patients often have symptoms of upper respiratory tract viral infection. Such as fever, sore throat, cough, nasal congestion, runny nose, sneezing, fatigue, etc., may be accompanied by muscle and joint pain, abdominal pain, diarrhea, etc.. When pericarditis occurs, there is severe pain in the precordial area, which may radiate to the left side of the neck and the back of the left shoulder, accompanied by palpitations, chest tightness, etc. Deep breathing, change in position, coughing, swallowing may aggravate the pain.
Examination
1. Physical signs
Pericardial friction can be heard in the precordial area and left axillary region. Pericardial friction is a specific sign of pericarditis and can be heard in both systole and diastole. The cardiac border is normal or slightly enlarged. When the condition improves or pericardial effusion increases, the pericardial friction may disappear. The signs of pericardial effusion are weakened or absent apical pulsation, heart percussion shows that the heart turbid tone boundary is enlarged to both sides, pericardial friction disappears on auscultation, and the heart sounds are low and distant. Arrhythmia and tachycardia may occur in some cases.
2. Laboratory tests
(1) Peripheral whole blood cytology: lymphocytes and monocytes are increased.
(2) Immunological tests: Since there are many types of viruses that can cause pericarditis, immunological tests can be performed against certain viral antigens and specific antibodies to help differentiate between viral types.
(3) Virus isolation: Viruses can be isolated from throat swabs, feces, blood and other specimens in the early stages of the disease, and should be carefully analyzed in relation to their biological characteristics, pathogenic effects and the time of detection to determine whether they are the causative agent of pericarditis.
(4) Serum enzyme assay: Because viral pericarditis is often accompanied by myocarditis, certain enzymes such as creatine phosphokinase, lactate dehydrogenase, aspartate aminotransferase and lactate dehydrogenase isoenzymes are elevated in the patient’s serum.
3. Electrocardiogram
ST-segment elevation, flat or inverted T-wave, and QRS wave hypervoltage in the presence of pericardial effusion can be found in the early stage.
4. Echocardiography
Pericardial effusion and pericardial thickening can be found. In the late stage, pericardial narrowing may occur. At the same time, myocardial thickening, diastolic and systolic movement weakening can be found.
5. CT and magnetic resonance examination
When there is pericardial seepage, fluid-filled areas can be shown between the wall and dirty layers of the pericardium, and the amount of seepage can also be quantified. It has a greater diagnostic value in neoplastic pericarditis and can detect the presence of primary or metastatic tumors. In constrictive pericarditis, pericardial thickening is characterized by CT and magnetic resonance: the ventricles are normal in size while the right atrium, inferior vena cava and hepatic veins are dilated.
6. Pericardiocentesis
Pericardiocentesis is a diagnostic puncture, which can relieve the symptoms of cardiac tamponade; the pericardial fluid is taken for cell sorting and bacterial culture, to identify the causative organisms and search for tumor cells; antibiotics and chemotherapeutic drugs are injected into the pericardial cavity. If the amount of pericardial effusion is large, pericardiocentesis can be performed under the guidance of cardiac ultrasonography for examination of the composition, nature and etiology of the effusion, which will help to clarify the diagnosis.
7. Pericardial biopsy
Pericardial histologic and bacteriologic examination can be performed to clarify the etiology.
Diagnosis
The disease is diagnosed according to the following aspects:
1. the presence of symptoms of pericardial inflammatory chest pain.
2. pericardial friction sounds are audible on auscultation.
3. new widespread ST-segment elevation or PR-segment downshift on ECG.
4. Cardiac ultrasound suggests pericardial effusion or cardiac tamponade.
The diagnosis of the disease is confirmed by the presence of two of the above manifestations.
The following can be used as additional evidence to support the diagnosis:
1. Increased ESR, CPR, LDH, and white blood cell count in blood tests.
2. If pericardial myocarditis is present, inflammation involves the myocardium, and markers of myocardial injury such as CK-MB and cTnI are increased.
3. Pericardial fluid examination can determine the etiology.
4. Cardiac CT or MRI can help determine the cause.
5. If it is difficult to determine the cause, pericardioscopy and pericardial biopsy can be performed.
Treatment
1. General treatment
Attention to rest, it is advisable to keep the surrounding environment quiet, clean and air circulation. Patients with acute fever should be isolated.
2. Symptomatic treatment
Targeted treatment for the patient’s symptoms, if necessary, apply sedatives, oxygen, adrenocorticotropic hormone and cardiotonic agents. For patients with acute fever, prednisone or dexamethasone can be used. When the patient develops heart failure, cediran can be used.
3.Pathogen treatment
For RNA virus infection with early fever, ribavirin can be tried. For cases of DNA virus infection with early fever, acyclovir or famciclovir can be tried.
4. Treatment of complications and comorbidities
When the patient has complications such as pericardial constriction, pericardial tamponade, myocardial infarction, heart failure and so on. Corresponding treatment should be given to eliminate symptoms and restore cardiac function.
Prognosis
The prognosis of viral pericarditis is related to the severity of pericarditis, pre-existing diseases and the patient’s heart function. The more severe the pericarditis, the worse the prognosis. Patients with chronic viral pericarditis have a poor prognosis and tend to die of heart failure. Patients with acute viral pericarditis may recover within weeks to months after the onset of the disease.
Prevention
Avoiding contact with infectious agents is important in the prevention of viral pericarditis. At the same time, early detection and treatment are important to improve the prognosis of viral pericarditis.