Flu

Answer 1

Definition

The flu is a contagious infection of the nose, throat, and lungs caused by the influenza virus.

See also: Swine flu (H1N1)

Alternative Names

Influenza A; Influenza B

Causes, incidence, and risk factors

In temperate climates, influenza A usually arrives between early winter and early spring. Influenza B can appear at any time of the year.

The most common way to catch the flu is by breathing in droplets from coughs or sneezes. Less often, it is spread when you touch a surface such as a faucet handle or phone that has the virus on it, and then touch your own mouth, nose, or eyes.

Symptoms appear 1 - 7 days later (usually within 2 - 3 days). Because the flu spreads through the air and is very contagious, it often strikes a community all at once, causing an epidemic illness. This creates a cluster of school and work absences. Many students become sick within 2 or 3 weeks of the flu's arrival in a school.

Tens of millions of people in the United States get the flu each year. Most get better within a week or two, but thousands become sick enough to be hospitalized. About 36,000 people die each year from complications of the flu.

Sometimes people confuse colds and flu, which share some of the same symptoms and typically occur at the same time of the year. However, the two diseases are very different. Most people get a cold several times each year, and the flu only once every few years.

People often use the term "stomach flu" to describe a viral illness where vomiting or diarrhea is the main symptom. This is incorrect, as the stomach symptoms are not caused by the flu virus. Flu infections are primarily respiratory infections.

Symptoms

The flu usually begins abruptly, with a fever between 102 and 106 F. (An adult typically has a lower fever than a child.) The fever usually lasts for a day or two, but can last 5 days.

Other common symptoms include:

• Body aches
• Chills
• Dizziness
• Flushed face
• Headache
• Lack of energy
• Nausea
• Vomiting

Somewhere between day 2 and day 4 of the illness, the "whole body" symptoms begin to subside, and respiratory symptoms begin to increase.

The most prominent of the respiratory symptoms is usually a dry, hacking cough. Most people also develop a sore throat and headache. Runny nose (nasal discharge) and sneezing are common.

These symptoms (except the cough) usually disappear within 4 - 7 days. Sometimes, the fever returns. The cough and tiredness usually last for weeks after the rest of the illness is over.

Other symptoms may include:

• Loss of appetite
• Muscle achesand stiffness
• Stuffy, congested nose
• Sweating
• Worsening of underlying illness, such as Asthma or heart failure

Signs and tests

The evaluation of an individual with flu symptoms should include a thorough physical exam and, in cases where pneumonia is suspected, a chest x-ray.

Additional blood work may be needed. They may include a complete blood count, blood cultures, and sputum cultures.

The most common method for diagnosing the flu is an antigen detection test, which is done by swabbing the nose and throat, then sending a sample to the laboratory for testing.

The results of these tests can be available rapidly, and can help decide if specific treatment is appropriate. However, when flu is widespread in the community the diagnosis can often be made by simply identifying symptoms without further testing.

Treatment

If you have mild illness and are not at high risk, take these steps:

• Rest
• Take medicines that relieve symptoms and help you rest
• Drink plenty of liquids
• Avoid aspirin (especially teens and children)
• Avoid alcohol and tobacco
• Avoid antibiotics (unless necessary for another illness)

Most people who get seasonal flu will likely recover without needing medical care. Doctors, however, can prescribe antiviral drugs to treat people who become very sick with the flu or who are at high risk for flu complications. Ask your provider if you are high risk when you receive your flu immunization.

The main benefit of antiviral drugs is that they can shorten the time you have symptoms by about one day, but only if you start taking the medicine within 48 hours of when your symptoms began.

If you need treatment, the U.S. Centers for Disease Control and Prevention (CDC) recommend that your doctor give you zanamivir (Relenza) or osteltamivir (Tamiflu).

Children who are at risk of developing a severe case of the flu should also contact their provider for antiviral medication.

Expectations (prognosis)

Anyone at any age can have serious complications from the flu, but those at highest risk include:

• People over age 50
• Children between 6 months and 2 years
• Women more than 3 months pregnant during the flu season
• Anyone living in a long-term care facility
• Anyone with chronic heart, lung, or kidney conditions, Diabetes, or a weakened immune system

In most individuals who are otherwise healthy, the flu goes away within 7 to 10 days.

Complications

Possible complications, especially for those at high risk, include:

• Pneumonia
• Encephalitis(infection of the brain)
• Bronchitis
• Sinus infections
• Ear infections

Calling your health care provider

Call your health care provider if someone in a high-risk category develops symptoms of the flu, or if your illness seems severe.

Prevention

A yearly vaccine is recommended for children older than 6 months, adolescents, and adults.

The vaccine is available as a flu shot or a nasal spray-type flu vaccine.

For specific recommendations, see influenza vaccine.

References

Harper SA, Bradley JS, Englund JA, et al. Seasonal Influenza in Adults and Children - Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management: Clinical Practice Guidelines of the Infectious Diseases Society of America. Clinical Infectious Diseases. 2009;48:1003-32.

Committee on Infectious Diseases. Policy statement--recommendations for the prevention and treatment of influenza in children, 2009 -2010. Pediatrics. 2009 Oct;124(4):1216-26.

Jefferson T, Jones M, Doshi P, Del Mar C. Neuraminidase inhibitors for preventing and treating influenza in healthy adults: systematic review and meta-analysis. BMJ. 2009 Dec 8;339:b5106.

Linder JA. Influenza. In: Rakel P, Bope ET, eds. Conn's Current Therapy 2009. 1st ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 22.

Answer 2

Definition

The flu is an easily spread infection of the nose, throat, and lungs.

See also: Swine flu (H1N1)

Alternative Names

Influenza A; Influenza B

Causes, incidence, and risk factors

The flu is caused by an influenza virus.

Most people catch the flu when they breathe in tiny droplets from coughs or sneezes of someone who has the flu. You can also catch the flu if you touch something with the virus on it, and then touch your mouth, nose, or eyes.

Sometimes people confuse colds and flu. They do share some of the same symptoms. Most people get a cold several times each year. But they usually get the flu once every few years.

People call a viral illness that makes them throw up or have diarrhea the "stomach flu." This is incorrect. The flu mostly causes symptoms in the nose, throat, and lungs.

Symptoms

Flu symptoms usually begins quickly. Symptoms appear 1 - 7 days after you come in contact with the virus. They usually hit within 2 - 3 days.

The flu spreads easily. It often strikes a community all at once. Students or workers become sick within 2 or 3 weeks of the flu's arrival in a school or workplace.

The first symptom is a fever between 102 and 106 °F. An adult usually has a lower fever than a child.

Other common symptoms include:

• Body aches
• Chills
• Dizziness
• Flushed face
• Headache
• Lack of energy
• Nausea and vomiting

Between day 2 and day 4 of the illness, the fever and aches and pains begin to go away. But new symptoms occur, including:

• Dry cough
• Increased breathing symptoms
• Runny nose (clear and watery)
• Sneezing
• Sore throat

These symptoms (except the cough) usually go away in 4 - 7 days. Sometimes, the fever returns. The cough and feeling tired may last for weeks.

Some people may not feel like eating.

The flu can make asthma, breathing problems, and other long-term illnesses worse.

Signs and tests

Most people of do not need to see a doctor or nurse when they have flu symptoms. This is because most people are not at risk for a severe case.

People who become very sick with the flu may want to see a health care provider. People who are at high risk for flu complications may also want to see a doctor if they get the flu.

When many people in an area have flu, a doctor can make a diagnosis after hearing the symptoms. No further testing is needed.

There is a test to detect the flu. It is done by swabbing the nose and throat. The results of this test can be available rapidly. Sometimes, this test can help your health care provider decide the best treatment.

Treatment

HOW DO I TREAT MY SYMPTOMS?

Acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) help lower fever. Sometimes doctors suggest you use both types of medicine. Do NOT use aspirin.

A fever does not need to come all the way down to normal. Most people will feel better if their temperature drops by 1 degree.

Over-the-counter cold medicines may make some of your symptoms better. Cough drops will help with your sore throat.

You also need a lot of rest. Drink plenty of liquids. Avoid alcohol and tobacco.

WHAT ABOUT ANTIVIRAL MEDICATIONS?

Most people with milder symptoms feel better in 3 - 4 days. They do not need to see a doctor or take antiviral medications.

Doctors may give antiviral drugs to people who get very sick. People who are at high risk for problems from the flu may need these medicines.

These medicines may shorten the time you have symptoms by about 1 day. They work better if you start taking them within 2 days of your first symptoms.

Children at risk of a severe case of the flu may also need these medicines.

Expectations (prognosis)

Millions of people in the United States get the flu each year. Most get better within a week or two.

But thousands of people with the flu develop pneumonia or a brain infection. They need to stay in the hospital. About 36,000 people die each year of problems from the flu.

Anyone at any age can have serious complications from the flu. Those at highest risk include:

• People over age 65
• Children younger than 2 years
• Women more than 3 months pregnant during the flu season
• Anyone living in a long-term care facility
• Anyone with chronic heart, lung, or kidney conditions, diabetes, or a weakened immune system

Complications

Possible complications, especially for those at high risk, include:

• Pneumonia
• Encephalitis(infection of the brain)
• Menigitis
• Seizures

Calling your health care provider

Call your health care provider if you get the flu and think you are at risk for having complications. Also call your doctor if your symptoms are very bad.

Prevention

You can take steps to avoid catching or spreading the flu.

Stay in your apartment, dorm room, or home for at least 24 hours after any fever is gone. Wear a mask if you leave your room.

Avoid sharing food, utensils, cups, or bottles. Cover your cough with a tissue and throw away after use. Carry hand sanitizer with you. Use it often during the day and always after touching your face.

Cough into your sleeve if a tissue is not available. Avoid touching your eyes, nose, and mouth.

The Centers for Disease Control and Prevention (CDC) recommends that everyone 6 months and older should receive the influenza vaccine.

References

Jefferson T, Jones M, Doshi P, Del Mar C. Neuraminidase inhibitors for preventing and treating influenza in healthy adults: systematic review and meta-analysis. BMJ. 2009 Dec 8;339:b5106.

Fiore AE, Fry A, Shay D, et al; Centers for Disease Control and Prevention (CDC). Antiviral agents for the treatment and chemoprophylaxis of influenza --- recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2011 Jan 21;60(1):1-24.

Reviewed By

Review Date: 09/16/2011

David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine.

Answer 3

Your head is throbbing. Your throat is burning. You're coughing nonstop, and your whole body aches. This is no run-of-the-mill cold. You may have the flu. Let's talk about influenza, also known as the flu.

Winter is a time for sledding, snowball fights, and flu. Every winter, millions of Americans come down with this respiratory ailment and feel absolutely miserable.

Like the common cold, the flu is caused by a virus. But with the flu, it's the influenza virus that makes people so sick. The flu virus comes in a few different forms. Influenza A is most common between early winter and spring. You can catch influenza B year-round. Swine Flu, or H1N1, is a specific type of influenza A.

You catch the flu from someone who has it. When people with the flu sneeze or cough, they send a spray of droplets filled with the flu virus into the air. If you're unlucky enough to be nearby, you could breathe in those droplets. Or, you might touch a surface that the droplets have fallen on and then touch your nose or mouth.

Two to three days later, the first flu symptoms will appear. Usually you'll start running a fever. Then you'll feel achy and tired. You may have the chills and feel sick to your stomach. After a couple of days, the sore throat and cough will set in.

So, how do doctors treat the flu?

Because a virus causes the flu, antibiotics won't treat it, they only kill bacteria. There are antiviral medicines, but you need to start taking them within the first 2 days after your symptoms appear.

Until the illness runs its course, help yourself feel better by getting a lot of rest and drinking extra fluids. You can take an over-the-counter cold medicine to relieve your congestion and cough. Tylenol, Advil, or Motrin can bring down your fever and take some of the pain out of your sore throat. Aspirin isn't recommended during the flu, especially under age 18, because it could increase the risk for a rare, but serious, condition called Reye syndrome.

By itself, the flu usually isn't harmful. But it can make existing conditions like asthma and breathing problems worse. In older people or those with a weakened immune system, the flu can turn into pneumonia, bronchitis, and other more serious diseases.

For most healthy people, the flu is a short-term annoyance. They're stuck in bed for a week or two, and then their symptoms go away and they're back up and around. But thousands of people each year get very sick from the flu, especially the elderly, young children, and pregnant women. Many are hospitalized, and about 36,000 people die from flu complications.

To avoid getting the flu, eat well, get plenty of exercise and sleep, and practice good hygiene. Wash your hands often with warm water and soap or use an alcohol-based hand sanitizer. Don't share cups, plates, or utensils, especially during flu season. And most effective, get your flu shot every fall to protect you through the whole flu season.

Reviewed By

Review Date: 10/25/2011

Alan Greene, MD, Author and Practicing Pediatrician; also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

Answer 4

Influenza, commonly known as the flu, is a viral respiratory illness that can cause mild to severe symptoms like fever, cough, body aches, and fatigue. It can be prevented through annual vaccination and good hygiene practices such as handwashing. Treatment typically involves rest, fluids, and sometimes antiviral medications.