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 effects
- Hypersensitivity reactions: Bronchospasms and allergy-like reactions reported.
- Diarrhea, nausea, vomiting, headache, dizziness, sinusitis, cough, throat infections
- Some 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. �
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 �JH, Farrar �J, Han �AM, et al. Avian influenza A (H5N1) infection in humans. N Engl J Med. 2005;353(13):1374-1385.22 Tran �TH, Nguyen �TL, Nguyen �TD, 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 �HN, Lu �HZ, Cao �B, 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.