Flu – Symptoms, Causes and Treatment

Influenza (say: in-floo-en-zah) is also called the flu. It's an infection that causes fever, chills, cough, body aches, headaches, and sometimes earaches or sinus problems. The flu is caused by the influenza virus (say: vy-rus). A virus is a microorganism (say: my-croh-or-gah-nih-zum), which means it's so small that you can't see it without a strong microscope.

Flu Causes

Somewhere between day 2 and day 4 of the illness, the "whole body" symptoms begin to subside, and respiratory symptoms begin to increase. The flu virus can settle anywhere in the respiratory tract, producing symptoms of a cold, croup, sore throat, bronchiolitis, ear infection, or pneumonia.

Flu Symptoms

Symptoms of influenza can start quite suddenly one to two days after infection. Usually the first symptoms are chills or a chilly sensation, but fever is also common early in the infection, with body temperatures as high as 39 °C (approximately 103 °F). Many people are so ill that they are confined to bed for several days, with aches and pains throughout their bodies, which are worse in their backs and legs.[1] Symptoms of influenza may include:

Body aches, especially joints and throat

Coughing and sneezing

Extreme coldness and fever

Although nausea, vomiting, and diarrhea can sometimes accompany influenza infection, especially in children, gastrointestinal symptoms are rarely prominent. The term "stomach flu" is a misnomer that is sometimes used to describe gastrointestinal illnesses caused by other microorganisms.

Preventing Seasonal Flu: Get Vaccinated

The single best way to prevent the flu is to get a flu vaccination each year. There are two types of vaccines:

The "flu shot" – an inactivated vaccine (containing killed virus) that is given with a needle. The flu shot is approved for use in people 6 months of age and older, including healthy people and people with chronic medical conditions.

The nasal-spray flu vaccine – a vaccine made with live, weakened flu viruses that do not cause the flu (sometimes called LAIV for “Live Attenuated Influenza Vaccine”). LAIV is approved for use in healthy* people 2-49 years of age† who are not pregnant.

Flu Diagnosis

You can usually diagnose flu yourself based on the characteristic of your symptoms. It is unusual for any other diagnostic tests to be necessary unless there are complications.

Your GP cannot normally say exactly which virus is causing your flu-like symptoms. The main role of laboratory diagnosis is to identify the main circulating types and strains of the flu virus.

Treatment of Flu

Usually, you'll need nothing more than bed rest and plenty of fluids to treat the flu. But in some cases, your doctor may prescribe an antiviral medication such as oseltamivir (Tamiflu) or zanamivir (Relenza).

These drugs, which treat both influenza A and B, work by deactivating an enzyme the virus needs to grow and spread. If taken soon after you notice symptoms, they may shorten your illness by a day or so.

Relenza ™ (Zanamir): This is a novel new drug only approved in the summer of 1999. It is an inhaled nasal spray that acts in the lungs, at the site of primary infection. In addition to treating the influenza type A and B, it successfully prevented flu in four out of five healthy family members who lived with someone already infected with flu.