Management of influenza.

Influenza is a contagious airborne viral illness characterized by abrupt onset of symptoms. Fever, myalgia, headache, rhinitis, sore throat, and cough are commonly reported symptoms. The diagnosis should be made clinically, and the decision to begin antiviral therapy should not be delayed for laboratory confirmation of influenza. The 2009 pandemic influenza A (H1N1) virus is expected to continue to circulate during the 2010-2011 season, but it is not certain whether it will replace or cocirculate with seasonal influenza A subtypes that have been circulating since 1977. The 2009 H1N1 virus is largely resistant to adamantanes, but it is sensitive to neuraminidase inhibitors such as oseltamivir. Neuraminidase inhibitors have modest effectiveness in reducing influenza-related symptoms in patients at low risk of complications. Patients at high risk of complications, including pregnant women, should be treated with antiviral agents, preferably within 48 hours of symptom onset. Family physicians should follow guidelines from the World Health Organization and the Centers for Disease Control and Prevention when treating patients with influenza or influenza-like symptoms.