Current perspectives of influenza
Physicians frequently use the term “the flu” to explain various symptoms of their office patients, but too often this diagnosis is a catchall term meaning “I don’t know what’s wrong with you.” The disease caused by the influenza virus is not a gastrointestinal syndrome characterized by nausea, vomiting, and diarrhea; it is not the “common cold” characterized by coryza and headache; and it is not generalized aches and pains; nor does it occur in the summer, except rarely and under unusual circumstances.
Influenza is an acute infectious disease caused by an RNA containing myxovirus. This disease begins abruptly with fever, frequently recurring short chills, headache, malaise, retroorbital eye pain especially on eye motion, hacking, irritating, nonproductive cough, and severe myalgias. The paucity of respiratory symptoms relative to the intensity of the systemic symptoms is impressive. As is true with many infectious diseases, influenza may have a wide spectrum of manifestations ranging from inapparent infection (up to 25% of cases) to rapidly overwhelming pneumonia causing death in hours to days. In general, the disease tends to be mild; however, the impact of influenza on the community may be substantial. It is estimated that the 1968 Hong Kong influenza epidemic cost the US economy 3.5 to 5.0 billion dollars. In addition, 30,000 more deaths than the number expected for the same time period (“excess mortality”) were attributed to the Hong Kong flu virus. Since that time, except for one epidemiologic season, there have been annual outbreaks of influenza resulting in 2,000 to. . .