Influenza, including the A/H3 variant viruses, joins the ranks of common contagious conditions causing seasonal disease. In the general population, the prevalence does not increase with age; patients with flu-like symptoms aged 18-59, 60-74, and 75+ get the type A influenza diagnosis in 12.2%, 6.6%, and 5.4% of cases, respectively, and all influenza infections affect up to 20% of the total population. In hospitalized pediatric patients, A/H3 is the second most diagnosed strain after A/H1; influenza-related hospitalizations peak every August to September, and all infections affect 5-20% of children, with life-threatening complications being more widespread in those younger than 5.For epidemiological trends, categorized into HA and NA lineages, influenza A viruses undergo genetic changes in both children and adults, including antigenic shifts, can co-circulate with type B infections, have season-specific peaks, and spread through inhaling the infected individuals’ respiratory droplets.
In pediatric patients, common risk factors for influenza and complications are the preschool age (<5), unsafe living or health conditions conducive to immune weakening or increases in viral load (HIV/AIDS, obesity, etc.), and chronic illnesses.For pathophysiological mechanisms, influenza viruses, including those in the A/H3 strain, engage in replication in the respiratory epithelium, which causes the infection of immune cells and viral protein synthesis and could lead to lung compromise/inflammation.Children’s signs/symptoms typical for seasonal flu viruses pertain to general well-being (fever reaching up to 105°F, fatigue, or chills), the gastrointestinal system (nausea, emesis, or diarrhea), and the respiratory system (cough, rhinorrhea, nasal congestion, or pharyngitis). Type A strains differ from type C strains in symptoms’ severity.
Influenza, including the A/H3 strain infections, is preventable through flu vaccines with annual revaccination, self-isolation, hand hygiene, and practices for respiratory protection, but the influenza virus’s changes pose barriers to prompt vaccine development. Concerning diagnostic workup, symptom evaluation, molecular RP panel tests, rapid influenza diagnostic tests or antigen tests, and polymerase-chain reaction-based approaches to testing are available.For treatment/management, suspected and confirmed influenza cases involve antiviral drug use, including neuraminidase inhibitors effective against both type A and type B viruses, adamantine antiviral drugs active only against type influenza, or analgesic and antipyretic drugs against fever.For care standards, antiviral treatment is recommended in uncomplicated influenza cases, including the specified strain, with oseltamivir (oral suspension/tablets) and peramivir (IV antiviral) as the safest options for children younger than 7.Pre-existing disorders should also be considered to provide the appropriate plans of care.
The patient’s clinical presentation is predominantly typical and incorporates various common signs of influenza. Specifically, fever, nasal congestion, rhinorrhea, sore throat, and abdominal pain present in the child’s case represent the condition’s most widespread manifestations.At the same time, relatively rare atypical features, such as seizure-like symptoms, was denied. The features that slightly differ from the typical clinical picture are mild radiographic abnormalities and the patient’s productive cough; dry cough is much more common in the specified condition.Therefore, despite the condition’s seriousness, which finds reflected in the fever’s duration and the highest documented body temperature, the clinical manifestations are not severely atypical.
Regarding the topic’s importance to clinicians, studying the various manifestations of influenza in pediatric patients is crucially important to provide faster and more effective responses to infections complications, including the atypical signs. Infants and preschool children with influenza might develop a plethora of symptoms, for instance, new-onset neurological symptoms, seizure-like episodes, mental status alterations, and chronic disease exacerbations.Since influenza-related deaths in pediatric populations are not extremely rare, clinicians’ preparedness for assessing and reacting to complicated influenza cases is a priority to protect public health.
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