July 07, 2007

Respiratory Problems - Influenza

Quick Fact
The upper respiratory tract includes the:

nasal cavity
ethmoidal air cells
frontal sinuses
maxillary sinus

The functions of the upper respiratory tract are to move air to and from the lungs, and to filter, moisten, and warm the air.

Upper respiratory infection (URI) is an imprecise term that covers any infectious-disease process that usually involves the respiratory system starting with the nose and ending just before the lungs. The infections could be caused by viruses or bacteria, and include conditions such as the common cold, influenza, sinus problems, minor sore throat, and so forth.

Sometimes, bronchitis (inflammation of the bronchi) is called an upper respiratory infection. However, because the bronchi are found in the lungs, bronchitis is actually a lower respiratory infection or lung condition.


Influenza ( flu) is a highly contagious viral respiratory tract infection. An estimated 10 to 20 percent of the population in the US contract influenza each year. Influenza is characterized by the abrupt onset of fever, muscle aches, sore throat, and a nonproductive cough.

Flu Season Statistics
Although each flu season is different, approximately 10 to 20 percent of the population will get the flu each year. Among those who get the flu, one percent will require hospitalization and 8 percent of those hospitalized may die from the flu or its complications. In fact, the flu kills approximately 20,000 Americans every year.

Influenza can make people of any age ill. Although most people are ill with influenza for only a few days, some have a much more serious illness and may need to be hospitalized. Influenza can also lead to pneumonia and death.

Influenza viruses are divided into three types, designated as A, B, and C.

Influenza types A and B are responsible for epidemics of respiratory illness that occur almost every winter and are often associated with increased rates for hospitalization and death. Efforts to control the impact of influenza are focused on types A and B.

Influenza type C usually causes either a very mild respiratory illness or no symptoms at all. It does not cause epidemics and does not have the severe public health impact that influenza types A and B do.

Influenza viruses continually mutate or change, which enables the virus to evade the immune system of its host. This makes people susceptible to influenza infection throughout their lives. The process works as follows:

A person infected with influenza virus develops antibody against that virus.
The virus mutates or changes.
The "older" antibody no longer recognizes the "newer" virus.
Reinfection occurs.

The older antibody can, however, provide partial protection against reinfection. Currently, three different influenza strains circulate worldwide: two type A viruses and one type B. Type A viruses are divided into subtypes based on differences in two viral proteins called hemagglutinin (H) and neuraminidase (N). The current subtypes of influenza A are designated A(H1N1) and A(H3N2).

According to the National Center for Health Statistics (a division of the Centers for Disease Control and Prevention, CDC):

108 million cases of flu are reported in the US annually.
Approximately 192 million days will be spent in bed because of the flu each year in the US.

What causes influenza?
The influenza virus is generally passed from person to person by airborne transmission (i.e., sneezing or coughing). But, the virus can also live for a short time on objects -- such as doorknobs, pens, pencils, keyboards, telephone receivers, and eating or drinking utensils. Therefore, it may also be spread by touching something that has been handled by someone infected with the virus and then touching your own mouth, nose, or eyes.

What are the symptoms of the flu?
The following are the most common symptoms of the flu. However, each individual may experience symptoms differently. Influenza is called a respiratory disease, but the whole body seems to suffer when a person is infected. People usually become acutely ill with any, or all, of the following symptoms:

high fever
clear nose
sneezing at times
cough, often becoming severe
severe aches and pains
fatigue for several weeks
sometimes a sore throat
extreme exhaustion

Fever and body aches usually last for three to five days, but cough and fatigue may last for two weeks or more. Although nausea, vomiting, and diarrhea may accompany the flu, these gastrointestinal symptoms are rarely prominent. "Stomach flu" is an incorrect term sometimes used to describe gastrointestinal illnesses caused by other microorganisms.

The symptoms of the flu may resemble other medical conditions. Always consult your physician for a diagnosis.

Treatment for influenza:
Specific treatment will be determined by your physician based on:

your age, overall health, and medical history

extent and type of influenza, and severity of symptoms

your tolerance for specific medications, procedures, or therapies

expectations for the course of the disease

your opinion or preference
The goal of treatment for influenza is to help prevent or decrease the severity of symptoms. Treatment may include:

medications to relieve aches and fever (Aspirin should not be given to children with fever without first consulting a physician.)

medications for congestion and nasal discharge
bed rest and increased intake of fluids

New flu treatments:
The flu vaccine is still the preferred method for preventing the flu. However, several new medications have shown promise in reducing the duration of the illness and severity of symptoms, including:

Relenza (zanamivir) - Relenza is an oral mist containing an anti-viral drug. Approved by the US Food and Drug Administration (FDA) in 1999, Relenza appears to provide relief for flu symptoms, especially if taken within two days of the onset of the flu.

Tamiflu (oseltamivir phosphate) -Tamiflu, like Relenza, was approved by the US Food and Drug Administration (FDA) in 1999 to treat the flu within 40 hours of the onset of symptoms. Tamiflu is a pill taken over a period of five days to block the flu virus from leaving infected cells.

Flu-mist ™ - Flu-mist™,
an experimental nasal-spray form of the flu vaccine, shows great promise in studies supported by the National Institute of Allergy and Infectious Diseases (NIAID). The nasal-spray vaccine protected several children exposed to a strain of flu not covered by the regular flu shot.

Symmetrel (amantadine) and Flumadine (rimantadine) - Two anti-viral medications, amantadine and rimantadine, have been shown to reduce the severity and duration of the illness when taken shortly after the onset of symptoms. Most anti-viral medications need to be taken within 48 hours of the onset of the flu.

New flu treatments continue to be investigated for future use. Always consult your physician concerning any treatment medication.

To be continued...