Influenza in children

Influenza in children is an acute infection from influenza A, B, C; characterized by respiratory infection, intoxication and high likelihood of secondary bacterial complications. Influenza in children occurs with high fever (up to 39-40 ° C), chills, general weakness, catarrhal phenomena (rash, runny nose, dry cough, bladder hyperemia). The diagnosis of influenza in children is based on clinical and epidemiological data, laboratory evidence of the virus (RIF, PCR, ELISA, RSK, RTGA). Symptomatic treatment of influenza in children is carried out through antipyretic, desensitizing, expectorant; etiotropic therapy – antiviral drugs.

Influenza in children belongs to the group of acute respiratory viral infections (ARVI), which also includes parainfluenza, adenovirus infection, respiratory syncytial infection, rhinovirus infection. Every year, the flu causes seasonal epidemics that affect up to 30% of the population, half of whom are children and adolescents. Children from 3 to 14 years old are most susceptible to influenza. At a Child is the influenza up to 4-5 times higher than in adults. Influenza in children often occurs with complications (compliance with bronchitis, pneumonia, sinusitis, etc.), exacerbation of chronic diseases, so the prevention of influenza epidemics is a serious pediatric problem.

Causes of Influenza in Children

Influenza is a highly infectious infection that is easily transmitted from person to person. Seasonal influenza epidemics in children caused by RNA viruses contain three types – A, B and C. The main surface antigens of the influenza virus are hemagglutinin (H) and neuraminidase (N), on which antigen subtypes of viruses are isolated.

The most highly variable antigen structure has a type A virus capable of causing an epidemic or pandemic. 15 presents its hemagglutinin subtypes (H1-H15) and neuraminidase – 10 subtypes (N1-N10). Usually circulate during seasonal influenza, H1N1 and H3N2 strains. Type A virus strains are common among humans, birds and pets.

The antigenic variability of the type B virus is less pronounced; As a rule, the pathogen causes local outbreaks or epidemics within the same country. Mass outbreaks of type B flu are often associated with or coincide with outbreaks of type A influenza. Type B flu only circulates in the human population, more often among children.

The influenza C virus has a stable antigenic structure; infects humans and pigs; only causes sporadic cases of the disease. Therefore, all flu vaccines (Influvac, Vaxigripp, Grippol, Inflex B, Agrippol, etc.) contain topical antigens of viruses A and B during this epidemic season.

Influenza viruses in children are mainly spread through droplets in the air during the conversation, sneezing, coughing. Children can also get influenza from contaminated hygiene products, toys and other items. The variability of weather conditions (fluctuations in air humidity and air temperature) contributes to the spread of influenza in children, a decrease in immunoreactivity, hypovitaminosis, a lack of sunlight and occurrence in groups of children.

Influenza viruses enter the body through the nose or oropharynx and are fixed in the cylindrical epithelium of the respiratory tract. With viruses, influenza hemagglutinin are attached to the cage and thanks to neuraminidase, destroying cell membranes, penetrates into the cell, where it begins the production of viral proteins and viral RNA replication. Then new viruses emerge from the host cells, hit other healthy cells and continue the reproductive process. In clinical terms, these processes are expressed in catarrhal inflammation. Through the damaged epithelial barrier, the viruses enter the bloodstream and are transported through the body, which leads to flu-like poisoning.

Influenza symptoms in children

The time of the hidden virus carrying lasts from a few hours up to 2-4 days. The onset of influenza in children is acute, with the intoxication syndrome predominating over catarrhal phenomena. In an infant, the only manifestation of influenza can be a high fever; in children under 5 years – high fever up to 39-40 ° C, runny nose and cough; in older children – fever, sweating, chills, dry cough, sweat and sore throat.

The general toxic effect on the body is accompanied by a worsening of appetite, lethargy, adynamy, headache, myalgia and arthralgia, vomiting. Capillary redoxicosis causes an increase in the permeability of the vascular walls, the development of hemorrhagic syndrome – nosebleeds, bleeding on the skin and mucous membranes, vascular scleral injection. Influenza in children can cause toxic damage to the central nervous system: encephalopathy, neurotoxicosis, convulsions, hallucinations, delirium. From the side of the cardiovascular system, tachycardia and muffled heart sounds are recognized; from the side of the urinary organs – microalbuminuria, microhematuria, a decrease in diuresis.

The severity of catarrhal manifestations and intoxication symptoms isolate mild, moderate, severe, and hypertoxic forms of influenza in children. With typical mild and moderate flu in children, the condition improves after 3-4 days, but the catarrhal inflammation lasts 1.5-2 weeks. In convalescence, asthenia can persist for a long time (rapid fatigue, weakness, sweating). Hypertensive form of influenza in children occurs with a high percentage of mortality due to fatal pulmonary edema, fulminant pneumonia, DIC syndrome, acute lung failure, cardiovascular and kidney failure.

Complications of influenza in children are divided into respiratory and non-respiratory. The most common complications of the first group occur in children under 5 years of age and include viral and secondary bacterial pneumonia caused by pneumococci, pathogenic staphylococci, hemolytic streptococci; false cereals, bronchiolitis, otitis media, sinusitis. Complications of the non-respiratory type include myocarditis, myositis, encephalitis, Reye’s syndrome, etc.

Children under the age of 2 and children with concomitant diseases (bronchial asthma, congenital heart defects, immune deficiency, diabetes, kidney diseases) are most at risk of serious complications from influenza.

Diagnosis of influenza in children

When diagnosing influenza in children, the pediatrician takes into account the epidemiological data and the clinical picture (fever, intoxication, catarrhal symptoms, physical changes).

Laboratory confirmation of influenza in children can be carried out using express methods (PCR and RIF), which detect viral antigens in smears of the nasal mucosa and oropharynx. In some cases, serological and virological methods are used (ELISA, RSK – complement fixation reaction, RTGA hemagglutination inhibition reaction, etc.).

To rule out complications of influenza children may need consultation specialists (child otolaryngologist, child neurologist, pediatric pneumology, pediatric nephrology), examine the general analysis of urine and blood, chest x-ray, bacteriological examination of sputum, blood cultures for sterility.

Differential diagnosis of influenza in children should be carried out with other SARS, enterovirus infection, hemorrhagic fever, prodromal stage of hepatitis A and measles, mononucleosis.

Treatment of influenza in children

Treatment of children with mild and moderate forms of influenza is carried out at home. Children of younger age, as well as with severe or complicated infections, are shown in an infectious hospital stay. During the period of fever, it is necessary to observe bed rest, drink plenty of warm drink.

Causal treatment of influenza in children should be as early as possible be administered. In pediatric patients, the following antiviral drugs:. Rimantadine, umifenovir, seltamivir, alpha-interferon, tilorona etc. symptomatic influenza therapy in children receiving antipyretic and anti-inflammatory drugs (paracetamol, ibuprofen), expectorants (ambroxol, bromhexine, fenspirid), antitussive drugs, prenameloxadin drugs Instilling vasoconstrictor nasal drops etc ..

used antihistamines, vitamin B complex, a complex drug treatment of influenza in children. With the development of laryngitis tracheitis, effective ultrasound inhalation (healing, alkaline). In the event of bacterial complications appointed anti-infectives (penicillins, macrolides, cephalosporins, etc.). In the period of recovery from the flu in children recommended to receive adaptogens and immunomodulators.

Prediction and prevention of flu in children

Typical cases of seasonal flu usually lead to the recovery of children. Danger to life exists in severe, hypertoxic and complicated forms of influenza in children at risk.

In order to prevent mass outbreaks of seasonal infections and to increase collective immunity, an additional vaccination of children against influenza is carried out annually. With the incidence of a child in the family, influenza, other children and family members, it is necessary to carry out emergency prophylaxis with antiviral drugs and interferons. During the epidemic of influenza, measures are taken to separate children (isolation of patients, limitation of mass events, extraordinary holidays), anti-epidemic measures are carried out (wet cleaning of rooms with disinfectants, ventilation, quartz).