Influenza
Also known as: Flu or Grippe
What is it?
Influenza is a viral infection that is highly
contagious.
Who gets it?
Influenza outbreaks occur throughout the world,
usually during the winter.
What causes it?
There are three different strains of the
influenza virus, called A, B, and C, that are
responsible for outbreaks of the flu. However,
most flu cases are caused by influenza A. The
influenza B and C viruses are less common and
cause an illness with milder symptoms. The virus
is inhaled, usually by being near an infected
person who coughs or sneezes. It can also be
caught by touching something that has been
contaminated by an infected person’s secretions.
The virus attacks cells in the upper respiratory
tract.
What are the symptoms?
Anywhere from 24 to 48 hours after infection,
flu symptoms suddenly begin. Common symptoms are
body aches, headache, high fever, chills, and
fatigue. Body and head aches can be severe enough
that the infected person wants to stay in bed. As
the fever subsides, respiratory symptoms begin
with a sore throat, mild cough, and runny nose.
However, the cough can become severe and
long-lasting. Flu complications, or secondary
infections, include bronchitis, sinus or ear
infections, and heart and lung problems,
particularly in the elderly. You should see a
doctor when symptoms include high fever, chest
pains with breathing, and a cough that brings up
thick mucous. It can take weeks for the patient to
recover from the weakness and fatigue brought on
by the flu. If a child with the flu has symptoms
that include nausea and vomiting, as well as
confusion or delirium, and the child has been
treated with aspirin, he or she needs immediate
medical treatment for possible Reye’s syndrome.
Reye’s syndrome is a complication of aspirin use
in children under the age of 18. The influenza
virus does not usually cause stomach upset and
diarrhea.
How is it diagnosed?
In most cases, the flu is correctly diagnosed
by the patient or a family member and does not
require a visit to the doctor. However, the virus
can be diagnosed by your healthcare provider
according to its distinct set of symptoms, as well
as a blood test or culture of the infected
person’s secretions. If there appears to be a
secondary infection, there are additional tests,
such as physical examination, throat cultures, and
chest x-rays, for diagnosis. Anyone at risk for
severe complications from the flu should see a
doctor.
What is the treatment?
In most cases, the flu must simply run its
course. Symptoms can be relieved with pain
relievers such as acetaminophen, naproxen,
aspirin, or ibuprofin. Children under the age of
18 should not be given aspirin because of the risk
of Reye’s syndrome. Doctors also recommend plenty
of rest, fluids, and good nutrition. You should
not return to normal activities until you feel
fully recovered because you will find that you
tire easily even after the symptoms are gone. Keep
in mind that antibiotics are not effective against
a viral infection. However, antibiotics may be
used to treat a secondary bacterial infection,
such as a sinus or ear infection. Some
over-the-counter medications are designed
specifically for flu symptoms. While these may
provide some relief, you’ll find this with any
medication that contains ingredients that relieve
pain, coughing, and fever. Antiviral drugs are
available through a doctor’s prescription, and are
especially recommended for people for whom the flu
is more likely to cause more serious
complications. These include the elderly and those
with weakened immune systems. These drugs are
called amantadine and rimantadine, and can reduce
the duration of the flu, as well as the severity
of fever and respiratory symptoms. They must be
taken as soon as possible after symptoms begin and
are effective against the type A influenza virus
only. Like any drug, they can cause side effects,
which your doctor should discuss with you. Another
type of antiviral, oseltamivir phosphate, is
effective against type A and B influenza and is
available as a suspension so it can be take by
children older than one year. Alternative flu
treatments include acupuncture and acupressure,
aromatherapy, increased doses of vitamin C, and
herbal remedies such as echinacea, which
stimulates the immune system, and goldenseal and
garlic, which are antivirals. Consult your doctor
before trying any alternative treatments and to be
sure you are taking safe amounts of vitamins. Most
people recover fully from the flu without medical
treatment. However, for the sick and the elderly,
the flu is a serious illness that can result in
death from secondary infections and other
complications.
Self-care tips
A flu vaccine is available every year before
flu season begins. It is given as an injection.
Each year, the vaccine consists of the virus
strains that are expected to cause flu outbreaks
that year. Getting the vaccine helps your body
create antibodies, which are infection-fighting
cells, that will protect you from the flu virus.
It is recommended that everyone gets a yearly
vaccine. However, it is especially important for
the elderly and people of any age with chronic
illnesses (including asthma or other chronic
respiratory illnesses, diabetes, HIV/AIDS, kidney
disorders, cancer patients, and organ transplant
patients), as well as pregnant or nursing women,
who are more likely to develop serious
complications. People who work in nursing homes or
other healthcare facilities where they are more
likely to be exposed to the virus, and people
traveling to foreign countries, should also
receive the vaccine. You should get the vaccine
around two to six weeks before the flu season
begins. In the United States, most cases of the
flu are reported from late December to early
March. Children can also receive the vaccine, but
should receive two doses, one month apart, if they
have never been exposed to the influenza virus
before. The vaccine will not cause the flu, and
serious side effects from the vaccine are unusual.
Some people may have one to two days of mild
symptoms. This is more common in people who have
never been exposed to the influenza virus. Most
people also feel a bit of soreness around the site
of the injection. The influenza vaccine should not
be given to infants or to people who are allergic
to eggs. The vaccine is prepared with hen eggs. In
these cases, amantadine or rimantadine can be used
as a preventive measure against the virus. You can
help avoid exposure to many illnesses by washing
your hands frequently, especially before eating.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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