Fast Five Quiz: Key Aspects of Influenza

Michael Stuart Bronze, MD


March 31, 2020

The presentation of influenza virus infection varies. Upon examination, patients may have some or all of these findings:

  • Fever of 100°-104°F: Fever is generally lower in elderly patients than in young adults and can be absent in some patients

  • Tachycardia, which most likely results from hypoxia and/or fever

  • Pharyngitis: Even in patients who report a severely sore throat, findings may range from minimal infection to more severe inflammation

  • Eyes may be red and watery

  • Skin may be warm to hot depending on core temperature status; patients who have been febrile with poor fluid intake may show signs of mild volume depletion with dry skin

  • Pulmonary findings may include dry (nonproductive) cough with clear lungs or rhonchi, as well as focal wheezing

  • Nasal discharge or stuffiness (rhinitis) is not uncommon in most patients, especially children

  • Fatigued appearance

Patients with influenza who have preexisting immunity or who have received the vaccine may have milder symptoms.

Myalgias are common and range from mild to severe. Frontal or retro-orbital headache is common and may be severe. Ocular symptoms develop in some patients with influenza and include photophobia, burning sensations, or pain upon motion. Patients with influenza may develop rhinitis of varying severity, but it is generally not the chief symptom in adults, although it is more common in children.

Cough and other respiratory symptoms may be initially minimal but frequently progress as the infection evolves. Patients may report nonproductive cough, cough-related pleuritic chest pain, and dyspnea. Children may experience diarrhea.

Read more on the presentation of influenza.


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