Influenza

Susan McDiarmid, EdD, MS, PA-C and Michelle E Duffelmeyer, MD Reviewed 04/2024

BASICS

DESCRIPTION

Acute, typically self-limited, febrile infection caused by orthomyxovirus influenza types A and B marked by inflammation of nasal mucosa, pharynx, conjunctiva, and respiratory tract

EPIDEMIOLOGY

DIAGNOSIS

HISTORY

Sudden onset of:

Fever (37.7–40°C), especially within 3 days of illness onset
Anorexia. Chills, sweats, malaise, myalgia, arthralgia
Headache. Sore throat/pharyngitis
Nonproductive cough...

TREATMENT

Symptomatic treatment (saline nasal spray, analgesic gargle, antipyretics, analgesics, expectorants, suppressants)
Cool-mist or ultrasonic humidifier to increase moisture of inspired air
Couns...

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Mild cases: follow up typically not required. Moderate/severe: follow up until symptoms and secondary sequelae resolve.

PROGNOSIS

Good

COMPLICATIONS

Sepsis. Pneumon...

REFERENCES

Centers for Disease Control and Prevention. Preliminary Estimated Influenza Illness, Medical visits, Hospitalizations, and Deaths in the United States—2022-2023 Influenza Season. https://w...

ADDITIONAL READING

Sriwilaijaroen N, Vavricka CJ, Kiyota H, et al. Influenza A Virus Neurominidase Inhibitors. Methods in Mol Biol. 2022;2556:321-353. doi: 10.1007/978-1-071...

CODES

ICD10

J10.08 Influenza due to other identified influenza virus with other specified pneumonia
J11.89 Influenza due to unidentified influenza virus with other manifestations
J10.81 Influenza due to ...

CLINICAL PEARLS

Influenza is an acute, (typically) self-limited, febrile infection caused by influenza virus types A and B.
All persons >6 months should be vaccinated against influenza on an annual ...

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