Coronavirus is an acute infectious pathology with a predominantly aerogenic mechanism of infection caused by an RNA-containing coronavirus. Specific for coronaviruses is the defeat of the upper respiratory tract, less often – the intestines and stomach. Clinically, the infection is manifested by moderate fever and symptoms of intoxication. Diagnosis of the pathological process involves the detection of the virus and antibodies to the pathogen in the blood serum. Treatment includes etiotropic antiviral drugs and symptomatic therapy (antipyretic, expectorant, local vasoconstrictor and others).
ICD 10
B34.2 Coronavirus, unspecified
General information
Coronavirus is an acute viral disease that spreads by airborne droplets. Nosology was first described in 1965 in a patient with acute rhinitis, in 1975 the coronavirus itself was isolated. Now the family of these viruses includes more than 30 species that are widespread everywhere, and is constantly being updated: one of the last in 2015 in South Korea, the Middle East coronavirus (MERS) was isolated. It is generally believed that this pathogen accounts for up to 4-15% of annual cases of ARVI, the largest number of cases of the disease is recorded in winter and spring.
The epidemic of atypical pneumonia that struck China and other Asian countries in 2002-2003 is known, officially called severe acute respiratory syndrome (SARS). In January 2020, a new outbreak of coronavirus infection was recorded in China.
Causes
The causative agents of the disease are a family of RNA-containing coronaviruses. Within the family, there are three groups of infectious agents that are dangerous to humans: human coronavirus 229 E, human OS-43 virus and human intestinal coronaviruses. The cause of the appearance of a new type of virus (the causative agent of SARS) is considered to be a spontaneous mutation. The source of the infectious agent is a sick person (or carrier), the transmission routes are airborne and, much less often, contact–household, sold through toys contaminated with coronavirus, household items. Risk factors are childhood, decreased immunity and prolonged stay in poorly ventilated rooms with a large crowd of people.
The pathogen is unstable in the environment, dies when exposed to conventional doses of disinfectants, ultraviolet light and high temperatures. SARS-associated coronavirus has greater stability outside the body and can persist in the external environment for up to 4 days. Risk groups for the incidence of atypical coronavirus pneumonia are children, HIV-infected persons, the elderly and patients with severe chronic diseases (lung damage, diabetes mellitus, oncological processes), residents of communal apartments, dormitories, barracks, barracks, as well as medical personnel and service workers.
Characteristics of the COVID-2019 pathogen
The strain of the 2019-nCoV virus that caused an outbreak of infection in January 2020 in China belongs to coronaviruses. Its official name is COVID-2019. These pathogens circulate among animals, can be transmitted from them to people. The COVID-2019 virus is 70% of the genome similar to the SARS virus, the main reservoir in the wild is bats.
The outbreak of coronavirus pneumonia in 2020 began in Wuhan, Hubei Province, China, where there is a market with a huge assortment of seafood, domestic and wild animals. Currently, cases of the disease have been confirmed in more than 190 countries, including the USA, Thailand, Japan, South Korea, and Taiwan, in Europe (Italy, Germany, France, Great Britain, etc.), Russia, Australia, Iran, etc.
The transmission of coronavirus occurs by airborne droplets, long-term close and close contacts are dangerous (with animals, in the family, when caring for patients in a medical institution). The epidemiological situation is changing very rapidly.
Pathogenesis
The pathogenesis of coronavirus infection has not been sufficiently studied. After entering the upper respiratory tract, coronaviruses colonize the epithelial cells of the nasopharynx and oropharynx, actively multiply, destroying epithelial cells. With insufficient immune reactivity of the body, coronaviruses penetrate into alveolar epithelial cells, in the cytoplasm of which the pathogen is replicated. Finished virions by exocytosis are located on the outer membrane of the cell, which promotes the fusion of epithelial cells and the formation of syncytium.
In the future, there is excessive sweating of fluid and protein into the lung tissue, massive destruction of the surfactant and collapse of the alveoli with a sharp decrease in gas exchange. During recovery, the affected areas of lung tissue are replaced by connective tissue. Immunity after the disease is type-specific, persistent.
Symptoms of SARS
The incubation period is 2-3 days. The onset of the disease is acute, the symptoms of intoxication (weakness, headache, causeless fatigue) are poorly expressed. Body temperature rarely reaches high figures, most often does not exceed 38 ° C. The main manifestation of coronavirus infection is an abundant watery transparent discharge from the nose, which is replaced by a mucous rhinorrhea. Difficult nasal breathing and decreased sense of smell are characteristic. In children and weakened persons, there is a tickling, sore throat, a rough cough without sputum and an increase in cervical lymph nodes.
Coronaviruses can only cause isolated damage to the digestive system, accompanied by nausea, vomiting, abdominal pain (mainly in the epigastrium) and liquid watery stools. Gastroenteritis usually proceeds benign, without the development of dehydration, although in the case of coronavirus damage to the digestive system of infants, rapid progression to exicosis is possible.
Signs of SARS are the absence of a runny nose, high fever (more than 39 ° C), a painful dry cough and progressive shortness of breath; in some cases, the so-called respiratory distress syndrome of adults develops, leading to severe respiratory failure.
Symptoms of COVID-19
Clinical manifestations – fever (88%), dry cough (68%), shortness of breath, respiratory distress syndrome, weakness, muscle pain. In blood tests, leukopenia, lymphopenia are detected, bilateral infiltrates are determined on radiographs of patients.
The differences between coronavirus 2020 from SARS and MERS, described so far, consist in a lower degree of severity of clinical manifestations, low mortality, low contagiousness, and the absence of nosocomial infection.
Complications
With timely medical treatment and timely treatment, the coronavirus proceeds benign. The most common complication is the addition of secondary inflammation (most often bacterial in nature) with the development of sinusitis, tonsillitis, otitis, bronchitis and pneumonia. With SARS, complications arise due to the progressive failure of the respiratory tract. The most formidable of them are pulmonary embolism, myocarditis, pericarditis, spontaneous pneumothorax, heart failure and cardiac arrhythmias. There is evidence of the detection of coronaviruses in cerebrospinal fluid in patients with multiple sclerosis.
Diagnostics
If coronavirus is suspected, it is mandatory to consult an infectious disease specialist, an otorhinolaryngologist and a therapist, a pulmonologist – after the appearance of symptoms of lung damage, a gastroenterologist – in the presence of gastroenteritis. Nosology diagnostics is carried out by laboratory and instrumental methods, including:
- Clinical and biochemical blood testing. In the blood test, leukopenia, lymphocytopenia and thrombocytopenia, anemia, acceleration of ESR are observed. When secondary bacterial flora is attached, leukocytosis appears. Biochemical indicators reflect an increase in the activity of AST, ALT, creatine phosphokinase, a decrease in total protein and hypoalbuminemia, rarely hypoglobulinemia.
- Identification of infectious agents. It is possible to isolate the pathogen from the nasal discharge, sputum, washing waters, vomit, liquid stool of the patient with the help of PCR from the first day of the disease. In dynamics (at the initial treatment of the patient and after 2 weeks) is carried out Blood ELISA for the presence of antibodies to coronavirus. The minimum increase in the titer of antibodies to confirm the diagnosis is twofold. The most informative ELISA becomes 10 or more days after the first clinical manifestations. For the purpose of differential diagnosis, a bacteriological examination of bowel movements and a coprogram are used.
- Radiation diagnostics. When signs of pneumonia appear, chest X-rays are performed, less often multispiral computed tomography (CT of the lungs) is used to exclude similar pathologies. The X-ray picture is usually characterized by unilateral interstitial lesion or bilateral focal drain pneumonia.
Differential diagnosis is carried out with other acute respiratory infections, influenza, Ku fever, pneumocystosis, tuberculosis, legionellosis, ornithosis, mycoplasmosis, bacterial rhinopharyngitis, bronchitis and pneumonia. It is necessary to differentiate this pathology with viral diarrhea, salmonellosis, food toxicoinfections, dysentery, enterovirus infection.
Therapy without complications involves outpatient treatment. It is recommended to limit contacts with others, isolate the patient in a separate room if possible, ensure daily wet cleaning and ventilation of the room. No special diet has been developed; preference should be given to light but nutritious dishes, exclude fried, fatty, alcohol, adhere to frequent fractional nutrition and increase the consumption of liquid, mainly boiled water at room temperature.
Treatment involves etiotropic (ribavirin, interferon preparations) and symptomatic therapy (vasoconstrictive nasal drops, the use of sprays and solutions for irrigation of the posterior pharyngeal wall, antipyretics, expectorants; solutions for oral rehydration and sorbents are recommended for gastroenteritis). It is not recommended to use antibiotics without clinical manifestations and bacteriological confirmation. In the presence of complications of coronavirus disease, the advantage is given to drugs with a wide spectrum of action.
Detection or suspicion of SARS is an indication for hospitalization in an infectious hospital. Therapy of atypical pneumonia according to the WHO protocol is carried out in intensive care wards using a combination of antibiotics (levofloxacin, clarithromycin, amoxicillin with clavulanic acid) with an antiviral agent (ribavirin) and glucocorticosteroids (methylprednisolone). For patients with SARS, among others, promising drugs are those containing surfactant.
Prognosis and prevention
In the absence of complications, a complete recovery occurs within 7-10 days. The natural susceptibility of people to coronaviruses is low, and infection occurs only with prolonged close contact (most often in everyday life). With severe lung tissue damage (SARS), mortality reaches 20-38% of cases. Of those with SARS who were admitted to hospitals at a late stage of the disease or who have concomitant pathologies and are over 45 years old, the mortality rate increases by an average of 9.5%. Fibrous changes in the lungs can cause further development of chronic respiratory failure and permanent cardiac disorders.
Means of specific prevention of coronavirus infection (vaccines) have not been developed. To prevent the disease, it is recommended to lead a healthy lifestyle, hardening, feasible physical activity and a balanced diet. Important methods are the use of disposable medical masks in the cold season, avoiding mass events indoors, traveling in crowded public transport, daily ventilation and regular wet cleaning.
