Influenza (acute respiratory viral illness)
Summary/Definition
Influenza is an acute respiratory viral disease caused by influenza viruses and affects the upper respiratory tract. The influenza virus is one of the viruses that cause colds. The disease is called the same name as the virus itself: “influenza.” The period of seasonal activity for influenza is considered to be from October to May, when the weather is cold and dry. Influenza viruses are divided into three main groups: A, B, and C. Influenza A and influenza B viruses mainly cause people to get colds (acute respiratory infections). The influenza C virus rarely causes serious infection in humans, usually resulting in a mild ailment with symptoms that are not epidemiological in nature. Mutations within the viruses continue to occur, resulting in new variants – viruses with antigens lacking immunity. These types of viruses spread rapidly among humans, causing pandemics and epidemics.
Symptoms
The symptoms of influenza are different from those of the common cold. Influenza is characterized by the sudden onset of respiratory symptoms (cough, sore throat, etc.) and systemic symptoms (fever, fever, chills, headache, muscle and joint pain, fatigue, etc.). Children may experience excessive salivation, difficulty eating, nervousness, sleep disturbance, gastrointestinal disorders (nausea, vomiting, diarrhea, abdominal pain), and febrile convulsions. Unlike the common cold, influenza is less common, but much more serious, and can cause fatal complications, so the patient should undergo a differential diagnosis of influenza from the common cold and receive targeted treatment since modern antiviral treatments and effective vaccines against influenza viruses are available today.
Diagnostics
If during an influenza epidemic, a person experiences symptoms similar to the main symptoms of influenza, it can be clinically confirmed that they are infected with influenza viruses. Influenza-like symptoms can be easily confirmed by an antigen test, real-time PCR (RT-PCR) test, virus microflora isolation test or gene amplification test in a pharyngeal swab.
Treatment and course of the disease
There are two types of antiviral drugs effective against influenza viruses: adamantanes (amantadine, rimantadine, etc.), which are effective only against influenza A viruses, and neuraminidase inhibitors, which are effective against both influenza A and B viruses. In particular, it is important to administer antiviral drugs as early as possible because influenza increases the risk of severe complications such as, pneumonia, hospitalization and even death in children, infants, the elderly and patients with serious chronic diseases. Usually, flu symptoms are mild and the patient’s condition improves after 2-3 days of fever. In cases where a high fever persists and the patient has cough, yellow sputum, chest pain, difficulty breathing, etc., it is necessary to exclude pneumonia in him. Influenza patients are treated with antibiotics if acute bacterial complications are suspected, such as secondary bacterial pneumonia, and if acute bacterial complications are confirmed. Symptomatic treatment is mainly prescribed to relieve the patient’s influenza condition. To relieve headaches, muscle aches and fever, paracetamol is prescribed, the administration of which allows the patient to provide sufficient rest and sleep necessary for the restoration of immunity. Aspirin may be another drug prescribed for the flu, but it is contraindicated in children under 18 years of age as it can cause Reye’s syndrome.
Complications
Complications of the upper respiratory tract (croup, acute sinusitis, acute otitis media, etc.) often occur in children with influenza. Influenza can lead to complications such as viral pneumonia, lower respiratory tract diseases, exacerbation of chronic obstructive pulmonary disease, bacterial pneumonia caused by secondary infections (Haemophilus bacillus, Staphylococcus aureus, etc.), which require mandatory hospitalization and inpatient treatment of the patient, as in severe cases they can lead to death. In addition to respiratory complications, prolonged treatment of influenza can lead to such serious diseases as myositis, rhabdomyolysis, myocarditis, toxic shock syndrome, central nervous system disorders (Guillain-Barré syndrome, encephalitis), Reye’s syndrome, and others.
