The number of flu patients is growing daily, again children are a particularly vulnerable group. Influenza viruses are classified into subtypes depending on the presence of hemagglutinins (hemagglutinin -H) and neuraminidase (neuraminidase – N) as surface proteins. Influenza A and B are the seasonal causes of epidemics, influenza C causes sporadic cases. The A/H5N1 strain, known as ” bird flu “, periodically causes pandemics and has a more severe course, with a higher incidence of complications.
The flu virus is highly contagious and its most characteristic is that it occurs with a high fever. There may be several accompanying symptoms: chills, muscle and joint pain, headache, dizziness, pharyngitis, rhinitis, non-productive cough, cervical lymphadenopathy, and even conjunctivitis. The onset is always sudden with a sudden temperature rise.
Conjunctivitis, gastrointestinal involvement, and rhinitis are more common in infants and children than in adults.
Typical symptoms appear after a short incubation period, about 2-3 days after contact with a sick person. Fever and complaints of muscle and joint pain, headache, and fatigue last from 3-4 days to about 2 weeks. Complaints from the upper respiratory tract
are quickly added, with the appearance of a runny nose, inflammation of the throat (pharyngitis, tonsillopharyngitis), and a dry, irritating cough.
Some are at a particularly increased risk of complications, in children risk factors such as chronic respiratory diseases, chronic cardiovascular diseases, chronic renal failure, diabetes mellitus, immunosuppression or prolonged stay in medical institutions should be taken into account.
Complications occur around the 4-5th day after the beginning of the infection. The influenza virus can lead to the development of both primary viral pneumonia and secondary bacterial pneumonia. Other possible complications in the course of influenza are the appearance of croup, myositis, myocarditis, toxic shock syndrome, development of Guillain-Barre syndrome, Ray syndrome, acute respiratory distress syndrome, etc.
How is the diagnosis made?
The influenza virus has a pronounced seasonality for temperate latitudes and a characteristic clinical picture. Influenza should always be suspected in cases of contact with a patient with a confirmed diagnosis.
The diagnosis is confirmed with the help of tests, the most available and widely distributed are rapid flu tests. There are combined variants that detect antigens of both influenza A, and influenza B, and in combination with other SARS Cov-19 viruses, which work on the principle of immunochromatographic analysis. Nasal/nasopharyngeal secretions or saliva are used for the procedure. The result is ready in minutes. In severe infection data and complications, additional influenza virus typing is discussed, as avian influenza A (H5N1) tends to develop pandemics and causes severe complications with greater frequency.
Treatment
The most effective way of prevention is immunization. Vaccines provide good protection, and after administration, at least 10-14 days are needed to achieve an immune response and effective protection. With this type, two doses are required for primary immunization, with an interval of at least 4 weeks.
Antiviral therapy is mandatory for certain groups of high-risk patients – children with bronchial asthma, congenital heart malformations, etc.
Treatment for all includes primarily symptomatic remedies. Antipyretics, respectively containing paracetamol or ibuprofen, are applied, in high-febrile conditions that are not affected by the applied treatment, analgin can be given once a day in the form of oral drops.
Adequate oral fluid intake is monitored. Depending on the accompanying symptoms, ready-made rehydration solutions may also be offered. If it is impossible to take fluids by mouth, a doctor should be consulted immediately and the need for parenteral rehydration should be assessed.
The initiation of antiviral therapy should be at the discretion of the attending physician, taking into account the age and severity of the manifestations and contact with higher-risk patients.
Approved for therapy so far are:
- Oseltamivir and zanamivir (can be used for treatment as well as prevention when in contact with a sick person);
- Peramivir ;
- From August 2022, baloxavir can be used in children over 5 years of age.
References:
1. Influenza B Virus-associated Pneumonia in Pediatric Patients: Clinical Features, Laboratory Data, and Chest X-ray Findings;
2. Pediatric Influenza, Itzhak Brook, MD, MSc; Editor-in-Chief: Russell W Steele, MD;
3. Influenza , https://www.cdc.gov/flu/index.htm
