Summary
Definition
History and exam
Key diagnostic factors
- cough
- influenza-like illness
- conjunctivitis
- dyspnea
- fever
- rales, rhonchi
- wheeze
- decreased breath sounds
- tachypnea
Other diagnostic factors
- abdominal pain, vomiting, diarrhea
- altered mental status
- seizures
Risk factors
- close contact with infected birds or poultry
- close contact with infected animals or mammals
- recent travel to a country with H5N1 virus outbreaks
- environmental exposure to H5N1 virus
- close contact with infected humans
- laboratory work with H5N1 virus
Diagnostic tests
1st tests to order
- CBC with differential
- LFTs
- chest x-ray
- pulse oximetry
- sputum Gram stain
- sputum and blood bacterial culture
- real-time reverse transcription polymerase chain reaction (rtRT-PCR)
Tests to consider
- viral culture
Treatment algorithm
close contact of confirmed or probable case
suspected or probable or confirmed infection
Contributors
Authors
Timothy M. Uyeki, MD, MPH, MPP
Chief Medical Officer
Influenza Division
National Center for Immunization and Respiratory Diseases
Centers for Disease Control and Prevention
Atlanta
GA
Disclosures
TMU declares that he is an unpaid member and clinical Chair of the World Health Organization Guidelines Developmental Group: Clinical Management of Influenza Guidelines 2023-2024.
Acknowledgements
Dr Timothy M. Uyeki would like to gratefully acknowledge Dr Justin R. Ortiz, a previous contributor to this topic.
Disclosures
JRO declares that he has no competing interests.
Peer reviewers
Richard Martinello, MD
Professor
Departments of Internal Medicine and Pediatrics
Yale School of Medicine
New Haven
CT
Disclosures
RM declares that he has no competing interests.
An De Sutter, MD, PhD
Associate Professor
Department of General Practice and Primary Health Care
Ghent University
Belgium
Disclosures
ADS declares that she has no competing interests.
References
Key articles
Centers for Disease Control and Prevention. Interim guidance on the use of antiviral medications for treatment of human infections with novel influenza A viruses associated with severe human disease. Sep 2024 [internet publication].Full text
Centers for Disease Control and Prevention. Highly pathogenic avian influenza A(H5N1) virus: interim recommendations for prevention, monitoring, and public health investigations. Dec 2024 [internet publication].Full text
Centers for Disease Control and Prevention. Interim guidance on specimen collection and testing for patients with suspected infection with novel influenza A viruses associated with severe disease or with the potential to cause severe disease in humans. Sep 2024 [internet publication].Full text
World Health Organization. Clinical practice guidelines for influenza. Sep 2024 [internet publication].Full text
Centers for Disease Control and Prevention. Interim guidance for follow-up of close contacts of persons infected with novel influenza A viruses associated with severe human disease or with potential to cause severe human disease, and use of antiviral medications for post-exposure prophylaxis. Aug 2024 [internet publication].Full text
Reference articles
A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.
Differentials
- Coronavirus disease 2019 (COVID-19)
- Community-acquired pneumonia
- Atypical pneumonia
More DifferentialsGuidelines
- Highly pathogenic avian influenza A(H5N1) virus: interim recommendations for prevention, monitoring, and public health investigations
- Interim guidance on the use of antiviral medications for treatment of human infections with novel influenza A viruses associated with severe human disease
More GuidelinesPatient information
Flu
Pneumonia
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