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Avian Flu

- Centers for Disease Control and Prevention. Avian influenza A virus infections in humans. http://www.cdc.gov/flu/avianflu/avian-in-humans.htm. Acessed July 3, 2015. - Gao пїЅHN, Lu пїЅHZ, Cao пїЅB, et al. Clinical findings in 111 cases of influenza A (H7N9) virus infection. N Engl J Med. 2013;368(24):2277-2285. - World Health Organization. Cumulative number of confirmed human cases for avian influenza A (H5N1) reported to WHO, 2003-2015. Updated June 23, 2015. World Health Organization Web site. http://www.who.int/influenza/humananimal interface/H5N1cumulativetablearchives/en/. Accessed July 3, 2015. - World Health Organization. Interim WHO surveillance recommendations for human infection with avian influenza A (H7N9) virus. World Health Organization Web site. http://www.who.int/influenza/humananimalinterface/influenzah7n9/en/. Accessed July 3, 2015. - World Health Organization. Risk Assessment of human infection with avian influenza A (H7N9) virus. Updated February 23, 2015. World Health Organization Web site. http://www.who.int/influenza/humananimalinterface/influenzah7n9/RiskAssessmentH7N9_23Feb20115.pdf?ua=1. Accessed July 3, 2015.

para>Pediatric treatment is weight based. Safety and efficacy not established for children <1 year of age

  • Oseltamivir 30 mg PO BID for 5 days ≤15 kg
  • Oseltamivir 45 mg PO BID for 5 days 16 to 23 kg
  • Oseltamivir 60 mg PO BID for 5 days 24 to 40 kg
  • Oseltamivir 75 mg PO BID for 5 days >40 kg

Postexposure prophylaxis: Dosing is weight based as above but administered once daily for 7 to 10 days.

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Geriatric Considerations

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Pregnancy Considerations

  • Oseltamivir is pregnancy Category C.
  • Use with caution only if potential benefits outweigh possible risk.
  • Unknown if distributed in breast milk

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ALERT

  • The use of amantadine (Symmetrel) and rimantadine (Flumadine) is not considered beneficial unless access to newer agents is unavailable.
  • Vaccine is available only through U.S. Strategic National Stockpile, to be distributed by public health officials.

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Second Line

  • Zanamivir (Relenza) is considered second-line agent. Not recommended for patients with underlying respiratory disease (asthma, chronic obstructive pulmonary disease).
  • Treatment (ages 13 to ≥65 years)Zanamivir 10 mg (2 inhalations) BID for 5 days
  • Postexposure prophylaxis (ages 13 to ≥65 years)Zanamivir 10 mg (2 inhalations) once daily for 7 to 10 days
  • Adverse effectsHypersensitivity reactions: Bronchospasms and allergy-like reactions reported.Diarrhea, nausea, vomiting, headache, dizziness, sinusitis, cough, throat infectionsSome adverse effects felt due to lactose in inhaler powder
  • Drug interactions: not metabolized by CYP450

Pediatric Considerations

  • Zanamivir is not licensed for use in children <7 years of age for treatment and <5 years for prophylaxis.
  • Treatment (7 to 13 years of age): zanamivir 10 mg (2 inhalations) BID for 5 days
  • Prophylaxis (5 to 13 years of age): zanamivir 10 mg (2 inhalations) once daily 7 to 10 days

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Geriatric Considerations

No dosage adjustment for renal or hepatic impairment

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Pregnancy Considerations

  • Zanamivir is pregnancy Category C.
  • Use only if potential benefits outweigh possible risk.
  • Unknown if distributed in breast milk
  • Other medications: broad-spectrum antibiotics: Follow hospital protocols for community-acquired pneumonia.
  • High-dose corticosteroids use is associated with increased mortality.

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INPATIENT CONSIDERATIONS

Admission Criteria/Initial Stabilization

  • If known H5N1 activity in the community or if patient has traveled to a country with H5N1 activity, admit if patient presents with severe acute respiratory illness, oxygen requirement, or serious unexplained illness (encephalopathy or diarrhea)
  • Treat with broad-spectrum antibiotics, antiviral agents, with or without corticosteroids, until lab confirmation of H5N1 virus is available.
  • Early ventilatory support (1,3)[B]

Nursing

  • Use standard and droplet precautions.
  • N-95 masks

Discharge Criteria

  • Educate patient and families about proper hand hygiene and respiratory precautions.
  • Postexposure prophylaxis should be given to family members and close personal contacts

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

PATIENT EDUCATION

  • Hand hygiene, cough etiquette (cough into elbow)
  • CDC Web site: http://www.cdc.gov/flu/avianflu/

PROGNOSIS

Mortality rate is high in aggressive H5N1 cases. Median time to death in such cases was 9 days (range 6 to 17 days) with or without treatment. пїЅ

COMPLICATIONS

  • Multiorgan failure, acute (1, 2, 3, 4)[C]
  • Renal dysfunction
  • Cardiovascular compromise-dilated cardiomyopathy; tachyarrhythmias
  • Ventilator-associated pneumonia; pulmonary hemorrhage; pneumothorax
  • Pancytopenia
  • Reye syndrome
  • Sepsis syndrome without documented bacteremia

REFERENCES

11 Beigel пїЅJH, Farrar пїЅJ, Han пїЅAM, et al. Avian influenza A (H5N1) infection in humans. N Engl J Med. 2005;353(13):1374-1385.22 Tran пїЅTH, Nguyen пїЅTL, Nguyen пїЅTD, et al. Avian influenza A (H5N1) in 10 patients in Vietnam. N Engl J Med. 2004;350(12):1179-1188.33 World Health Organization. Clinical management of human infection with avian influenza A (H5N1) virus. http://www.who.int/influenza/resources/documents/ClinicalManagement07.pdf?ua=1. Accessed July 3, 2015.44 Centers for Disease Control and Prevention. New laboratory assay for diagnostic testing of avian influenza A/H5 (Asian lineage). MMWR Morb Mortal Wkly Rep. 2006;55(5):127.

ADDITIONAL READING

  • Centers for Disease Control and Prevention. Avian influenza A virus infections in humans. http://www.cdc.gov/flu/avianflu/avian-in-humans.htm. Acessed July 3, 2015.
  • Gao пїЅHN, Lu пїЅHZ, Cao пїЅB, et al. Clinical findings in 111 cases of influenza A (H7N9) virus infection. N Engl J Med. 2013;368(24):2277-2285.
  • World Health Organization. Cumulative number of confirmed human cases for avian influenza A (H5N1) reported to WHO, 2003-2015. Updated June 23, 2015. World Health Organization Web site. http://www.who.int/influenza/human_animal_ interface/H5N1_cumulative_table_archives/en/. Accessed July 3, 2015.
  • World Health Organization. Interim WHO surveillance recommendations for human infection with avian influenza A (H7N9) virus. World Health Organization Web site. http://www.who.int/influenza/human_animal_interface/influenza_h7n9/en/. Accessed July 3, 2015.
  • World Health Organization. Risk Assessment of human infection with avian influenza A (H7N9) virus. Updated February 23, 2015. World Health Organization Web site. http://www.who.int/influenza/human_animal_interface/influenza_h7n9/RiskAssessment_H7N9_23Feb20115.pdf?ua=1. Accessed July 3, 2015.

CODES

ICD10

  • J09.X2 Flu due to ident novel influenza A virus w oth resp manifest
  • J09.X9 Flu due to ident novel influenza A virus w oth manifest
  • J09.X1 Influenza due to identified novel influenza A virus with pneumonia
  • J09.X3 Influenza due to ident novel influenza A virus w GI manifest

ICD9

  • 488.02 Influenza due to identified avian influenza virus with other respiratory manifestations
  • 488.09 Influenza due to identified avian influenza virus with other manifestations
  • 488.01 Influenza due to identified avian influenza virus with pneumonia

SNOMED

  • Avian influenza (disorder)
  • influenza due to influenza virus type A, avian, H5N1 strain (disorder)
  • Influenza due to Influenza A virus with upper respiratory signs (disorder)
  • Pneumonia due to Influenza A virus (disorder)

CLINICAL PEARLS

  • Consider avian influenza in patients presenting with acute febrile respiratory illness and recent travel to high-risk areas (especially Asia) or who have spent time on poultry farms.
  • Oseltamivir is first-line antiviral treatment.
  • Perform CBC, CXR, rapid tests for antigen detection, nasopharyngeal swabs for PCR, blood cultures, aspartate aminotransferase/alanine aminotransferase (AST/ALT)/CD4 if avian flu is suspected.
  • H7N9 avian flu appears to have less human-to-human transmission,but increased resistance to oseltamivir.