Respiratory syncytial viral infection( PC infection) - Causes, symptoms and treatment. MF.

Causes of MS infection
Symptoms and complications
Diagnosis
Treatment of
Prevention of

Respiratory syncytial infection is a group of acute respiratory viral infections that affect a fairly large group of people of mostly early childhood. Among the children of the first year of life, respiratory syncytial infection is the first place in the respiratory-respiratory syndrome group. With relatively easy flow in adults, in the children's age group, this infection can lead to the development of severe pneumonia and can lead to an unfavorable outcome.

Respiratory syncytial infection( RS infection) is an acute infectious viral disease with airborne transmission caused by the virus of the family Paramixoviridae, characterized by a predominant lesion of the lower respiratory tract( bronchitis, bronchiolitis, pneumonia).

RSI, target organ

The causative agent of RS infection was discovered in 1956( Morris, Savage, Blont) when the material was cultivated from chimpanzees during the episode of numerous rhinites among primates. In humans, a similar virus was isolated in 1957( Chanock, MyersRoizman) when examining children with bronchiolitis and pneumonia. The virus owes its name to one feature of its pathological effect, namely: the ability to form syncytium - a networked structure of cells with cytoplasmic processes between themselves, as well as tropism to the cells of the respiratory tract. Thus, the virus was called the "respiratory syncytial virus"( hereinafter RSV).

Causes of occurrence of RS-infection

The causative agent of is a respiratory syncytial virus( RSV) - an RNA-containing virus from the family of Paramixovieidae of Pneumovirus. Currently, two serological strains RSV( Long and Randall) are isolated, which do not have clear distinctions in properties, hence, are assigned to one serotype. The size of the virion varies from 120 to 200 nm, RSV differs polymorphism. RSV has several antigens in the composition:
- nucleocapsid B-antigen or complement-binding antigen( promotes the formation of complement-binding antibodies),
- surface A antigen( promotes the production of virus neutralizing antibodies).

Respiratory syncytial virus

The virus contains the M protein( membrane protein) required to bind to the membranes of infected cells, as well as F proteins, the GP protein( attachment proteins) that facilitate attachment to the target cell of the virus, followed by replication of RSV.

RSV is not very stable in the external environment: already at a heating temperature of 55-60 ° C it is inactivated for 5 minutes, it boils instantly. When frozen( minus 70 °) it retains its viability, but does not survive repeated freezing. The virus is sensitive to disinfectants - solutions of acids, ether, chloramine. It is sensitive to drying. On the skin of the hands, the virus can survive for 25 minutes, on objects of the environment - clothing, toys, tools in fresh secretions can last from 20 minutes to 5-6 hours.

In the human body, as in the culture of cells in the laboratory, RSV has a cytopathic effect - the appearance of pseudo-giant cells due to the formation of syncytium and the symplast( the networked formation of cells with cytoplasmic bridges between them, that is, the absence of a clear boundary between the cells and their specific fusion).

The source of the RS-infection is a sick person and a virus carrier. The patient becomes infectious 1-2 days before the appearance of the first symptoms of the disease and remains so for 3-8 days. The virus-carrier can be healthy( without signs of disease) and convalescent after the transferred illness( that is, after recovery, isolate the virus).

Infection mechanism - aerogenic, transmission path - airborne( when sneezing and coughing, spraying of aerosol with virus particles occurs in a 1.5-3-meter environment from the patient).Air-dust path is of little importance due to low virus resistance to drying. For the same reason, it is of little importance that the transfer is through a household contact through the objects of the surrounding situation.

Susceptibility to infection is universal and high, the children's population is more often ill. The disease is highly contagious, describes nosocomial outbreaks of infection in children's hospitals. Winter-spring seasonality is revealed, but sporadic cases are recorded year-round. Due to "passive immunity" infants( up to 1 year old) are seldom ill, except premature babies. Up to 3 years of age, almost all children already have PC-infection. During one season, outbreaks of MS infection last from 3 to 5 months.

Immunity after an MS-infected is unstable, transient( not more than 1 year).Repeated cases of infection in another epidemic season are described that can be erased with residual immunity or manifest in the absence of such.

Pathological effect of RSV in the human body

The entrance gates of the infection are the nasopharynx and the oropharynx. Here RSV multiplies in the epithelium of the mucosa. Further, it spreads to the lower respiratory tract - small caliber bronchi and bronchioles. It is here that the main pathological effect of RSV occurs - the formation of syncytia and symplasts - pseudo-gigantic cells are formed with cytoplasmic septa between themselves. In the lesion focus, there is inflammation and migration of specific cells - leukocytes and lymphocytes, mucosal edema, hypersecretion of mucus. All this leads to clogging of the respiratory tract by secretion and development of various kinds of disturbances in the respiratory lung excursion: the exchange of gases( O2, CO2) is disrupted, and there is a lack of oxygen. All this is manifested by shortness of breath and increased frequency of heartbeats. Perhaps the development of emphysema, atelectasis.

Also, RSV is able to induce immunosuppression( suppression of immunity), which affects both cellular immunity and humoral immunity. Clinically, this can explain the greater incidence of secondary bacterial lesions in MS infection.

Clinical symptoms of RS-infection

The incubation period lasts from 3 to 7 days. Symptoms of the disease are combined into 2 syndromes:

1) Infectious-toxic syndrome. The onset of the disease may be acute or subacute. The patient's body temperature rises from 37.5 to 39 ° and higher. The temperature reaction lasts about 3-4 days. The fever is accompanied by symptoms of intoxication - weakness, weakness, lethargy, headaches, chills, sweating, capriciousness. Immediately there are symptoms of nasopharyngitis. The nose is laid, the skin is hot to the touch, dry.

2) The respiratory tract syndrome, first of all, manifests itself as a cough. Cough in patients with PC-infection appears on the 1-2 day of the disease - dry, painful, persistent and prolonged. Along with the cough, the number of respiratory movements gradually increases, on the 3-4th day after the onset of the disease, signs of expiratory dyspnea( difficulty breathing out, which becomes noisy whistling and audible at a distance).Due to the fact that patients are more often children of early age, often there are attacks of suffocation, accompanied by a child's anxiety, pallor of the skin, pastoznost and puffiness of the face, nausea and vomiting. Older children complain of pain behind the sternum.

On examination, hyperemia( reddening) of throat, arch, posterior pharynx wall, enlargement of submandibular, cervical lymph nodes, injection of scleral vessels, and with auscultation of the patient, hard breathing, scattered dry and wet rales, blunting of percussion sound. Signs of rhinitis in MS infectionare expressed little and are characterized by small mucous secretions. Possible complications of respiratory syndrome, and in severe form - manifestations, are croup syndrome and obstructive syndrome.

The severity of the manifestations is directly dependent on the patient's age: the younger the child, the harder the disease progresses.

• The mild form is characterized by a low temperature response( up to 37.50), mild
symptoms of intoxication: small headaches, general weakness, dry cough. The mild form is more often recorded in older children.
• The medium-heavy form is accompanied by febrile temperature( up to 38,5-390), mild symptoms of intoxication, persistent dry cough and mild dyspnea( DN 1 degree) and tachycardia.
• Severe form manifested by a pronounced infectious-toxic syndrome, pronounced, persistent, prolonged cough, severe shortness of breath( DN 2-3 degrees), noisy breathing, circulatory disorders. With auscultation, an abundance of small bubbling rales, can be heard crepitation of the lungs. Severe form is most often observed in children of the first year of life, and severity is more associated with the phenomena of respiratory failure than with the severity of intoxication. In rare cases, pathological hyperthermia and convulsive syndrome are possible.

The duration of the disease is from 14 to 21 days.

In the analysis of peripheral blood leukocytosis, monocytosis, the appearance of atypical lymphomonocytes( up to 5%), neutrophil shift to the left with the attachment of secondary bacterial infection, increased ESR.

Features of symptoms in newborns and premature infants: a gradual onset, a mild fever is possible, on the background of a stuffy nose, a persistent cough appears, which is often confused with whooping cough. Children are restless, do not sleep much, eat badly, lose weight, rapidly develop symptoms of respiratory failure, inflammation of the lungs develops rapidly enough.

Complications and prognosis of RS-infection

Complications of RS-infection may be diseases of ENT organs, more associated with the attachment of secondary bacterial flora - otitis, sinusitis, pneumonia.

The prognosis for a typical uncomplicated course of a PC-infection is favorable.

Diagnosis of RS infection

Diagnosis of respiratory syncytial viral infection is based on:

1) Clinical and epidemiological data. Epidemiological data include contact with an ARVI patient, presence in public places, places of high crowding. Clinical data include the presence of 2 syndromes - infectious-toxic and respiratory, and most importantly - a feature of the respiratory syndrome in the form of bronchiolitis( see description above).Presence of the above signs at the age of up to 3 years. Differential diagnosis should be carried out with the entire group of acute respiratory viral infections, laryngitis, tracheitis of various etiologies, pneumonia.

2) Laboratory data - general blood test: leukocytosis, monocytosis, increased ESR, detection of atypical lymphomonocytic cells( 5%), possible neutrophil shift to the left.

3) Instrumental data - chest X-ray: strengthening of pulmonary pattern,
compaction of the roots of the lung, in some places emphysematous areas of the lung.

4) Specific laboratory data:
- virological examination of nasopharyngeal flushing with the help of RIF, express methods;
- serological examination of blood for antibodies to RSV by neutralization reaction, RSK, RTGA in paired sera with an interval of 10-14 days and detection of the growth of antibody titer.

Treatment of RS-infection

1) Organizational-regime measures: hospitalization of patients with moderate and severe disease, bed rest for the entire febrile period.

2) Drug therapy includes:

- Etiotropic therapy:
- antiviral agents( isoprinosine, arbidol, anaferon, tsikloferon, ingavirini others) depending on the child's age;
- antibacterial agents are prescribed with proven attachment of bacterial infection, pneumonia adherence and only by a physician.

- Pathogenetic treatment:
- antitussive, expectorant and anti-inflammatory syrups( erespal, lazolvan, bromhexine, sinecode, potions with althea root, with thermopsis);
- antihistamines( claritin, zirtek, zodak, cetrine, suprastin, erius and others);
- topical therapy( nasol, nasivin and others for the nose, phallimint, pharyngept and others for the throat).

- Inhalation therapy - steam inhalations with herbs( chamomile, sage, oregano), alkaline inhalation therapy, use of nebulizers with medicines.
- If necessary, administration of glucocorticosteroids.

Prevention of RS-infection

There is no specific prevention( vaccination).
Prevention includes epidemiological measures( timely isolation of the patient, timely treatment, wet cleaning of the room, antiviral prophylaxis of contact - arbidol, anaferon, influferon and other drugs);tempering children and promoting healthy lifestyles;prevention of hypothermia in the epidemic season of infection( winter-spring).

The doctor infektsionist Bykova N.I.