Influenza infection

Last reviewed: 7 Jan 2023
Last updated: 13 Dec 2022

Summary

Definition

History and exam

Key diagnostic factors

  • winter season
  • current influenza outbreak
  • unvaccinated
  • fever with cough
More key diagnostic factors

Other diagnostic factors

  • sore throat
  • cervical lymphadenopathy
  • dyspnea
Other diagnostic factors

Risk factors

  • age ≥65 years
  • age 6-59 months
  • chronic cardiovascular or respiratory conditions
  • diabetes
  • hemoglobinopathy
  • immunocompromise
  • chronic kidney disease (CKD)
  • pregnancy
  • caregivers and household contacts of high-risk groups
  • healthcare workers
More risk factors

Diagnostic investigations

1st investigations to order

  • clinical diagnosis
More 1st investigations to order

Investigations to consider

  • molecular assays
  • antigen detection tests
  • viral culture
  • serology
  • chest x-ray
More investigations to consider

Treatment algorithm

INITIAL

exposure to infected individual(s) in at-risk population

ACUTE

adults

children

Contributors

Authors

Kyle Eggleton, MBChB PhD FRNZCGP(Dist)

Associate Dean Rural

Department of General Practice and Primary Health Care

University of Auckland

Auckland

New Zealand

Disclosures

KE declares that he has no competing interests.

Rachel Roskvist, MBChB, FRNZCGP

Senior Lecturer

Department of General Practice and Primary Health Care

University of Auckland

Auckland

New Zealand

Disclosures

RR declares that she has no competing interests.

Bruce Arroll, MBChB PhD FRNZCGP

Department of General Practice and Primary Health Care

University of Auckland

Auckland

New Zealand

Disclosures

BA declares that he has no competing interests.

Acknowledgements

Dr Kyle Eggleton, Dr Rachel Roskvist, and Professor Bruce Arroll would like to gratefully acknowledge Dr Cristine Radojicic, a previous contributor to this topic.

Disclosures

CR declares that she is on Advisory boards for CSL Behring and Speakers Bureau Biocryst.

Peer reviewers

Waleed Javaid, MD, FACP, FIDSA

Associate Professor

Medical Director of Infection Control

Infectious Disease

Department of Medicine

SUNY Upstate Medical University

Syracuse

NY

Disclosures

WJ declares that he has no competing interests.

Rachel L. Miller, MD, FAAAAI

Associate Professor of Clinical Medicine and Environmental Health Sciences

Columbia University College of Physicians and Surgeons

New York

NY

Disclosures

RLM declares that she has no competing interests.

Mark Sands, MD, FAAAAI

Chief

SUNY Buffalo School of Medicine

Division Allergy and Immunology

Buffalo

NY

Disclosures

MS declares that he has no competing interests.

An De Sutter, MD, PhD

Associate Professor

Department of General Practice and Primary Health Care

Ghent University

Ghent

Belgium

Disclosures

ADS declares that she has no competing interests.

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