Differential diagnosis


• upper respiratory infection

• pneumonia

• acute bronchitis 

• acute exacerbation of chronic bronchitis 

• asthma exacerbation

• streptococcal pharyngitis

• RSV infection

• acute sinusitis in children and adolescents

• allergic rhinitis

• infectious mononucleosis

• severe acute respiratory syndrome (SARS) 

• recent vaccination with live, attenuated influenza 
vaccine 


Management


• antiviral treatment

  
  • efficacy (but results may vary with antiviral resistance patterns)
    • neuraminidase inhibitors may reduce time to symptom resolution by 0.5 to 3 days in children with influenza 
    • oseltamivir may reduce complications and hospitalization in children with influenza and chronic medical conditions 

  • recommended as soon as possible (before laboratory confirmation) for patients with suspected influenza who
    • have severe, complicated, or progressive illness

    • require hospitalization

    • are at higher risk for influenza complications

  • consider for any outpatient with confirmed or suspected influenza if the treatment can be started within 48 hours of illness onset

  • drug choice based on
    • type of virus circulating

    • antiviral resistance patterns

  • give treatment for 5 days with drug dosing based on age and weight
    • oseltamivir (Tamiflu) is given orally twice daily
      • 75 mg for adolescents and children > 40 kg (88 lbs)

      • 60 mg for children 24-40 kg (53 to 88 lbs)

      • 45 mg for children 15-23 kg (33 to 51 lbs)

      • 30 mg for children ≤ 15 kg (33 lbs)

      • 3 mg/kg children < 12 months old

    • zanamivir (Relenza)
      • 2 inhalations of 10 mg twice daily in children ≥ 7 years old

      • not recommended in patients with airways disease 

    • reduce doses to once daily if renal impairment 
(creatinine clearance 10 to 30 mL/minute)

    • adamantanes (amantadine [Symmetrel], rimantadine [Flumadine])
      • active against influenza A only

      • NOT recommended for treatment or prophylaxis of currently circulating influenza A due to resistance

• antipyretics

  
  • may reduce fever and provide analgesia

  • no evidence of any effect on course of illness

  • Combined or alternating acetaminophen and ibuprofen regimens may be more effective than either monotherapy for reducing fever in children. 

  • avoid aspirin due to association with Reye syndrome

• complementary medicine—insufficient evidence for treatment or prevention of influenza


Prevention


• antiviral prophylaxis 

  
  • may be considered for
    • high-risk close contacts

    • patients at higher risk for influenza complications

    • unvaccinated staff members in institutional settings

  • post-exposure prophylaxis
    • may be given for up to 10 days after the last known exposure only if antivirals can be started within 48 hours of exposure.

  • pre-exposure prophylaxis for unexposed children
    • in the community, give based on the duration of influenza activity for
      • up to 28 days for zanamivir

      • up to 42 days for oseltamivir 

  • in institutional settings, give for ≥ 2 weeks and until about 10 days after onset of illness in last ill child 

• exclusion from school for at least 24 hours after the last fever 

  
  • appropriate for most situations

  • not appropriate in healthcare settings and places with significant numbers of high-risk children

• vaccination

  
  • annual influenza vaccination are recommended for all persons ≥ 6 months old without contraindications

  • begin vaccination efforts as soon as vaccines are available and continue through illness season

• hand hygiene

  
  • may prevent influenza transmission in households if initiated within 36 hours of symptom onset.

Alan Drabkin, MD is a senior clinical writer for DynaMed (), a database of comprehensive updated summaries covering more than 3,200 clinical topics, and assistant clinical professor of population medicine at Harvard Medical School.

From the January 01, 2016 Issue of Clinical Advisor