Avian influenza or Bird Flu

Avian influenza - Acute

 

Definition  

Human infection with avian influenza A viruses

 

Medical History  

* Contact with infected poultry

 

Findings  

* Dyspnea - Acute

* Respiratory distress

* Diarrhea - Acute

* Fever

* Inspiratory crackles

* Tachypnea

* Abdominal pain - Acute

* Conjunctivitis

* Cough

* Headache

* Myalgia

* Pain in throat

* Vomiting

 

Tests  

 

Suspected avian influenza A (H5N1) infection  

* PCR test for avian influenza A: Influenza H5N1-specific reverse-transcriptase PCR testing conducted under Biosafety Level 2 conditions is the preferred method for diagnosing avian influenza A (H5N1) virus infection .

 

Suspected or known avian influenza  

* White blood cell count: Leukopenia, particularly lymphocytopenia, is a common finding associated with avian influenza A infection .

 

Suspected or known avian influenza  

* Platelet count: Mild-to-moderate thrombocytopenia is a common finding in patients infected with avian influenza .

 

Suspected or known avian influenza  

* Hepatic function panel: Mild-to-moderate elevations in aminotransferase levels are a common finding in patients infected with avian influenza virus .

 

Suspected or known acute renal failure  

* Blood urea nitrogen measurement: A BUN of 50 to 150 mg/100mL suggests serious renal impairment, and a BUN of 150 to 250 mg/100 mL is virtually diagnostic of severe glomerular dysfunction.

 

Suspected and known sepsis  

* Blood culture: In patients with suspected sepsis, at least 2 sets of blood cultures should be obtained, preferably from peripheral venipuncture before antimicrobial therapy is initiated, if obtaining such cultures does not cause a significant delay in antibiotic administration .

 

Suspected avian influenza A  

* Viral culture, Influenzavirus, type A, avian: Viral culture should not be attempted on specimens from patients suspected to have influenza H5N1, unless conducted under Biosafety Level 3 conditions with enhancements .

 

Suspected and known community-acquired pneumonia  

* Pulse oximetry: An assessment of oxygenation by pulse oximetry is indicated for all patients with clinical features suggestive of pneumonia as part of the initial clinical evaluation .

 

Suspected and known avian influenza  

* Plain chest X-ray: Most patients with avian influenza present with radiographic evidence of pneumonia, which tends to worsen with progression of the disease .

 

Hospitalized patients with community acquired pneumonia  

* Arterial blood gas analysis: A PaO2/FiO2 ratio ?250 is an indicator of severe pneumonia and a ratio <150 signals severe hypoxemia

 

Suspected avian influenza A infection  

* Avian influenza virus antibody assay: A 4-fold or greater rise in antibody titer using paired acute and convalescent serum samples indicates recent infection with influenza A (H5N1) and is required for serologic diagnosis .

 

Differential Diagnosis  

* Influenza

* Community acquired pneumonia - Acute

* Acute respiratory distress syndrome - Acute

* Gastroenteritis - Acute

* Viral encephalitis - Acute

 

Treatment  

 

Drug Therapy  

 

Treatment of avian influenza A (H5N1)  

 

OSELTAMIVIR PHOSPHATE  

Adults: 75 mg orally twice daily for 5 days (early mild infection) OR 150 mg orally twice daily for 7 to 10 days (moderate to severe infection); treatment should be initiated as early as possible, preferably within 2 days of illness onset

Pediatrics (>40 kg): 75 mg orally twice daily for 5 days ; treatment should be initiated as early as possible, preferably within 2 days of illness onset

Pediatrics (>23 to 40 kg): 60 mg orally twice daily for 5 days ; treatment should be initiated as early as possible, preferably within 2 days of illness onset

Pediatrics (>15 to 23 kg): 45 mg orally twice daily for 5 days ; treatment should be initiated as early as possible, preferably within 2 days of illness onset

Pediatrics (?15 kg): 30 mg orally twice daily for 5 days ; treatment should be initiated as early as possible, preferably within 2 days of illness onset

 

ZANAMIVIR  

Adults: 10 mg (2 inhalations) twice daily, approximately 12 hours apart, for 5 days ; treatment should be initiated as early as possible, preferably within 2 days of illness onset

Pediatrics (?7 years): 10 mg (2 inhalations) twice daily, approximately 12 hours part, for 5 days ; treatment should be initiated as early as possible, preferably within 2 days of illness onset

 

 

Fever  

 

ACETAMINOPHEN

Adults: 650 to 1000 mg orally every 4 hours as needed (maximum 4 g/day)

Pediatrics: 10 to 15 mg/kg orally every 4 to 6 hours as needed (maximum 5 doses/day)

 

IBUPROFEN

Adults: 400 mg orally every 4 to 6 hours as needed (maximum 3.2 g/day)

Pediatrics: 10 mg/kg orally every 6 to 8 hours as needed (maximum 40 mg/kg/day)

 

Procedural Therapy  

 

Suspected and known avian influenza  

* Infection control procedure: Patients with suspected or confirmed avian influenza should be managed with full barrier isolation precautions .

 

Suspected and known avian influenza with hypoxia  

* Oxygen therapy: Patients with avian influenza A(H5N1) virus infection should be monitored for oxygen desaturation and supported with supplemental oxygen to correct hypoxemia .

 

Respiratory distress  

* Airway management: Airway management must assume the first priority in the management of any seriously ill or injured patient .

 

Suspected and known avian influenza  

* Infectious disease notification: Health care facilities should report to public health authorities all available information regarding possible human cases of avian influenza .