Symptoms, Diagnosis and Treatment

What Are the Symptoms of Influenza?

Influenza is a respiratory infection with symptoms that can affect the entire body. Symptoms include:

  • Sudden onset of high fever
  • Headache, muscle aches and joint pain
  • Cough (usually dry)
  • Chills
  • Sore throat
  • Nasal congestion and runny nose
  • Fatigue

How Is Influenza Diagnosed?

It is hard to know for sure you have the flu on the basis of symptoms alone. A doctor's exam may be needed to tell whether you have developed the flu or a complication of the flu. There are tests that can determine if you have the flu as long you are tested within the first 2 or 3 days of illness.

If you develop flu-like symptoms and are concerned about your illness, especially if you are at high risk for complications of the flu, you should talk to your healthcare provider. There are rapid diagnostic tests that can be ordered and many providers use antiviral medications when they are confident of the diagnosis (see the treatment section below).

How Is Influenza Treated?

At this time, two antiviral drugs are available: oseltamivir (trade name Tamiflu®), which comes in pill form, and zanamivir (trade name Relenza®), which is a powder that comes in an inhaler. These two drugs, one inhaled and one in pill form, have been shown to reduce flu symptoms if started within a day or two of getting sick.

Anti-viral medicine is recommended for people with more severe illness, especially those who require hospitalization. Treatment with anti-viral medicine is most important for people with suspected or confirmed influenza who are at higher risk for complications, including:

  • Children younger than 2 years old
  • Adults 65 years and older
  • Pregnant women
  • People with certain chronic medical conditions, such as asthma or COPD, or with suppressed immune systems

It is important to note that people with chronic lung disease, including asthma, should not use the inhaled powder Relenza, because it sometimes worsens breathing problems.