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Influenza (flu) – Symptoms and causes

Publisher/Author : Pacific Cross

This post is also available in: Tiếng Việt (Vietnamese)


Know the basics

What is influenza?

Influenza, or the flu, is common a respiratory viral infection. Each year there are about 10% – 15% cases of influenza, affecting 250.000 – 500.000 people. The flu often begins suddenly and goes away after 7 to 10 days. The flu can be dangerous to some people, especially if they are infected with more advance types of flu virus.

Influenza often begins suddenly, lasts for 7 to 10 days, and goes away for most people. Most people recover completely. However, the elderly, the very young, and those with weak immune system can have a more severe course and even die from complications.

How common is influenza?

Influenza is extremely common and can affect patients at any age.  An adult may get influenza at least 2-3 times/year and 6-7 times/year for children. The flu is most common in the fall – the flu season. It can be managed by reducing your risk factors. Please discuss with your doctor for further information.

Know the symptoms

What are the symptoms of influenza?

You may have symptoms of influenza after 24 to 48 hours after exposure to the flu virus. The symptoms usually last 3 to 5 days. Some common symptoms of influenza are:

  • Headaches;
  • Fever up to 40°C;
  • Body chills;
  • Muscle aches;
  • Weakness, fatigue;
  • Stuffy nose;
  • Sore throat;
  • Cough;
  • Eyes sensitivity to bright light;
  • With some flu virus, diarrhea and vomiting, especially in adults.

There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.

When should I see my doctor?

If you have flu symptoms and are at risk of complications, see your doctor right away. Taking antiviral drugs within the first 48 hours after you first notice symptoms may reduce the length of your illness and help prevent more serious problems.

Know the causes

What causes influenza?

Influenza is caused by viruses. These are classified as type A, B, or C. Type A is most common. Some flu virus you might have heard of: the swine flu (H1N1), bird flu (H5N1, H7N9), etc.

People get the virus that causes influenza when they breathe in air that is infected with the virus. These viruses are spread when you are contacted by an infected object or animal. The flu virus might also live in small droplets of water that an infected person has cough or sneezed into the air. Eating the meat of an infected animal can give you the flu as well.

Know the risk factors

What increases my risk for influenza?

There are many risk factors for influenza. If you are frequently expose to an environment with virus, or if you have weakened immune system, you are at a higher risk of influenza. Some risks factor of influenza are:

  • Age.Young children under 5, especially those under 2 years, and adults older than 65.
  • Living conditions.People who live in nursing homes, military barracks or other closed unit facilities.
  • Weakened immune systems. Cancer treatments, anti-rejection drugs, corticosteroids and HIV/AIDS can weaken your immune system. This can make it easier for you to catch influenza and may also increase your risk of developing complications.
  • Chronic illnesses.Chronic conditions, such as asthma, diabetes or heart problems, may increase your risk of influenza complications.
  • Pregnancy.Pregnant women are more likely to develop influenza complications, particularly in the second and third trimesters.
  • Obesity.People who are very obese, with a body mass index (BMI) of 40 or higher, have an increased risk of complications from flu.

Understand the diagnosis & treatment

The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.

How is influenza diagnosed?

In most cases, the flu can be self-diagnosed. You might recognize it from its symptoms, such as fever and fatigue. There is a test called the Flu Test (or Rapid Flu Test and Influenza Antigen Test) designed to identify influenza virus.

This test is often used in the flu season to control the spreading. The Flu Test may involve taking a sample of liquid from a runny nose or using a blood sample. The doctor may also order a chest x-ray to check for pneumonia – a complication of influenza.

Testing is recommended in particular for people who are hospitalized, have weakened immune systems, or are otherwise at an increased risk of serious complications.

If influenza has already been identified in the community, a health practitioner may order a flu test to confirm the diagnosis and validate possible antiviral treatment.

How is influenza treated?

Most people who get the flu can treat themselves at home and often don’t need to see a doctor.  The best treatment is rest. Most people misunderstand that ani-biotics can cure the flu. However, taking anti-biotic will not make the flu any better, but also will increase your risk of building anti-biotic resistance.

If the symptoms make you feel uncomfortable, you can talk to your doctor about taking medication to treat specific symptoms. You can find some of these medication over-the-counter. Non-aspirin medicines, such as acetaminophen and ibuprofen, are used for pain relief; cough syrups to control the sore throat and coughing; and decongestants for stuffy nose.

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Lifestyle changes & home remedies

What are some lifestyle changes or home remedies that can help me manage influenza?

Some other non-medication methods can help you cope with influenza:

  • Drinking lots of fluids is the most important as it will keep you from dehydrated by the fever.
  • Taking a warm bath to relax your muscle and lessen muscle aches.
  • A humidifier in your house can help with making it easier to breathe.
  • Gargling with warm salt water or mouthwash may ease a sore throat.

To prevent catching the flu as well as spreading to other people, here are a few things you could do:

  • Get a flu vaccination. The best way to prevent the flu is to build immunity to the virus.
  • Avoid sharing personal objects.
  • If you have the flu, use hand sanitizer often, especially after touching your face and before touching public objects.
  • Wear a mask when you go outside and cover your mouth when you sneeze or cough.

If you have any questions, please consult with your doctor to better understand the best solution for you.


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