Acute respiratory infections are various acute infectious diseases that occur as a result of damage to the epithelium of the respiratory tract by RNA and DNA–containing viruses. Usually accompanied by fever, runny nose, cough, sore throat, lacrimation, symptoms of intoxication; may be complicated by tracheitis, bronchitis, pneumonia. The diagnosis of ARI is based on clinical and epidemiological data confirmed by the results of virological and serological analyses. Etiotropic treatment of acute respiratory viral infections includes taking antiviral drugs, symptomatic – the use of antipyretics, expectorants, gargling, instillation of vasoconstrictive drops into the nose, etc.
Acute respiratory infections (ARI) are airborne infections caused by viral pathogens that mainly affect the respiratory system. ARI are the most common diseases, especially in children. During the peak of the incidence of ARI, 30% of the world’s population is diagnosed, respiratory viral infections are several times higher in frequency of occurrence of other infectious diseases. The highest incidence is typical for children aged 3 to 14 years. The increase in morbidity is noted in the cold season. The prevalence of infection is widespread.
Acute respiratory infections are classified according to the severity of the course: there are light, moderate and severe forms. The severity of the course is determined based on the severity of catarrhal symptoms, temperature reaction and intoxication.
A are caused by a variety of viruses belonging to different genera and families. They are united by a pronounced affinity for the cells of the epithelium lining the respiratory tract. ARI can cause various types of influenza viruses, parainfluenza, adenoviruses, rhinoviruses, 2 RSV serovars, reoviruses. In the vast majority (with the exception of adenoviruses), pathogens belong to RNA-containing viruses. Almost all pathogens (except rheo- and adenoviruses) are unstable in the environment, quickly die when dried, the action of ultraviolet light, disinfectants. Sometimes ARI can cause Coxsackie and ESNO viruses.
The source of ARI is a sick person. The greatest danger is presented by patients in the first week of clinical manifestations. Viruses are transmitted by an aerosol mechanism in most cases by airborne droplets, in rare cases it is possible to implement a contact-household path of infection. The natural susceptibility of people to respiratory viruses is high, especially in childhood. Immunity after infection is unstable, short-term and type-specific.
Due to the multiplicity and diversity of types and serovars of the pathogen, multiple incidence of ARI in one person per season is possible. Approximately every 2-3 years, influenza pandemics associated with the emergence of a new strain of the virus are registered. Acute respiratory infections of non-influenza etiology often provoke outbreaks of morbidity in children’s groups. Pathological changes in the epithelium of the respiratory system affected by viruses contribute to a decrease in its protective properties, which can lead to bacterial infection and the development of complications.
Common features of ARI: a relatively short (about a week) incubation period, acute onset, fever, intoxication and catarrhal symptoms.
The incubation period for infection with adenovirus can range from two to twelve days. Like any respiratory infection, it begins acutely, with a rise in temperature, runny nose and cough. Fever can persist for up to 6 days, sometimes it occurs in two oxen. Symptoms of intoxication are moderate. Adenoviruses are characterized by the severity of catarrhal symptoms: abundant rhinorrhea, swelling of the nasal mucosa, pharynx, tonsils (often moderately hyperemic, with fibrinous plaque). The cough is moist, the sputum is clear, liquid.
There may be an increase and soreness of the lymph nodes of the head and neck, in rare cases – lienal syndrome. The height of the disease is characterized by clinical symptoms of bronchitis, laryngitis, tracheitis. A common sign of adenovirus infection is catarrhal, follicular or filmy conjunctivitis, initially, usually unilateral, mainly of the lower eyelid. After a day or two, the conjunctiva of the second eye may become inflamed. Children under two years of age may have abdominal symptoms: diarrhea, abdominal pain (mesenteric lymphopathy).
The course is long, often undulating, due to the spread of the virus and the formation of new foci. Sometimes (especially when affected by adenoviruses 1,2 and 5 serovars), a long-term carrier is formed (adenoviruses latently persist in the tonsils).
Respiratory syncytial infection
The incubation period, as a rule, takes from 2 to 7 days, for adults and children of the older age group, a mild course of catarrh or acute bronchitis is characteristic. There may be a runny nose, pain when swallowing (pharyngitis). Fever and intoxication are not characteristic of respiratory syncytial infection, subfebrility may be noted.
The disease in young children (especially infants) is characterized by a more severe course and deep penetration of the virus (bronchiolitis with a tendency to obstruction). The onset of the disease is gradual, the first manifestation is usually rhinitis with scanty viscous secretions, hyperemia of the pharynx and palatine arches, pharyngitis. The temperature either does not rise, or does not exceed subfebrile figures. Soon there is a dry obsessive cough of the type of whooping cough. At the end of the coughing attack, there is a release of thick, transparent or whitish, viscous sputum.
With the progression of the disease, the infection penetrates into smaller bronchi, bronchioles, respiratory volume decreases, respiratory insufficiency gradually increases. Shortness of breath is mainly expiratory (difficulty exhaling), breathing is noisy, there may be short-term episodes of apnea. On examination, there is an increasing cyanosis, auscultation reveals scattered small- and medium-bubbly wheezes. The disease usually lasts about 10-12 days, with a severe course, an increase in duration, recurrence is possible.
The incubation period of rhinovirus infection is most often 2-3 days, but it can range from 1-6 days. Pronounced intoxication and fever are also not characteristic, usually the disease is accompanied by rhinitis, abundant serous-mucous discharge from the nose. The amount of discharge is an indicator of the severity of the flow. Sometimes there may be a dry moderate cough, lacrimation, irritation of the eyelid mucosa. The infection is not prone to complications.
ARI can be complicated in any period of the disease. Complications can be both viral in nature and arise as a result of the addition of a bacterial infection. Most often, acute respiratory infections are complicated by pneumonia, bronchitis, bronchiolitis. Common complications also include sinusitis, sinusitis, and frontitis. Often there is inflammation of the hearing aid (otitis media), meningitis, meningoencephalitis, various kinds of neuritis (often neuritis of the facial nerve). In children, often at an early age, a rather dangerous complication can be a false croup (acute laryngeal stenosis), which can lead to death from asphyxia.
With high intoxication (in particular, characteristic of influenza), there is a possibility of seizures, meningeal symptoms, cardiac arrhythmias, and sometimes myocarditis. In addition, acute respiratory viral infections in children of different ages can be complicated by cholangitis, pancreatitis, infections of the genitourinary system, septicopiemia.
Diagnosis of ARI is carried out on the basis of complaints, survey data and examination. The clinical picture (fever, catarrhal symptoms) and epidemiological history are usually sufficient to identify the disease. Laboratory methods confirming the diagnosis are IFA, PCR (viral antigens are detected in the epithelium of the nasal mucosa). Serological research methods (ELISA of paired sera in the initial period and during convalescence, IFA, HI) usually clarify the diagnosis in retrospect.
With the development of bacterial complications of ARI, a consultation of a pulmonologist and an otolaryngologist is required. The assumption of the development of pneumonia is an indication for lung radiography. Changes on the part of the ENT organs require rhinoscopy, pharyngoscopy and otoscopy.
ARI is treated at home, patients are sent to the hospital only in cases of severe course or development of dangerous complications. The complex of therapeutic measures depends on the course, severity of symptoms. Bed rest is recommended for patients with fever until the normalization of body temperature. It is advisable to follow a full-fledged, protein- and vitamin-rich diet, and consume a lot of fluids.
Medicines are mainly prescribed depending on the predominance of one or another symptom: antipyretics (paracetamol and complex preparations containing it), expectorants (bromhexine, ambroxol, marshmallow root extract, etc.), antihistamines for desensitization of the body (chloropyramine). Currently, there are a lot of complex preparations that include active substances of all these groups in their composition, as well as vitamin C, which helps to increase the natural protection of the body.
Locally, vasoconstrictors are prescribed for rhinitis: naphazoline, xylometazoline, etc. With conjunctivitis, ointments with brom-naphthoquinone, fluorenonylglyoxal are placed in the affected eye. Antibiotic therapy is prescribed only in case of detection of an attached bacterial infection. Etiotropic treatment of ARI can be effective only in the early stages of the disease. It involves the introduction of human interferon, anti-influenza gammaglobulin, as well as synthetic drugs: remantadine, oxoline ointment, ribavirin.
Of the physiotherapeutic methods of treating acute respiratory viral infections, mustard baths, cupping massage and inhalations are widespread. Supportive vitamin therapy, herbal immunostimulants, adaptogens are recommended for people who have undergone acute respiratory viral infections.
Prognosis and prevention
The prognosis for ARI is mostly favorable. Deterioration of the prognosis occurs when complications occur, a more severe course often develops with the weakening of the body, in children of the first year of life, senile people. Some complications (pulmonary edema, encephalopathy, false croup) can lead to death.
Specific prevention consists in the use of interferons in the epidemic focus, vaccination with the use of the most common strains of influenza during seasonal pandemics. For personal protection, it is advisable to use gauze bandages covering the nose and mouth when contacting patients. Individually, it is also recommended to increase the protective properties of the body as a prevention of viral infections (rational nutrition, hardening, vitamin therapy and the use of adaptogens).
Currently, specific prevention of acute respiratory viral infections is not effective enough. Therefore, it is necessary to pay attention to general measures for the prevention of respiratory infectious diseases, especially in children’s groups and medical institutions. As measures of general prevention, there are: measures aimed at monitoring compliance with sanitary and hygienic standards, timely identification and isolation of patients, limiting crowding of the population during epidemics and quarantine measures in foci.