Bronchitis

Bronchitis

Bronchitis is inflammation of the main air passages to the lungs. Bronchitis may be short-lived (acute) or chronic, meaning that it lasts an extended time and often recurs. Bronchitis is the inflammation of the mucous membranes of the bronchi and the airways that carry airflow from the trachea into the lungs. Bronchitis can be divided into two categories, acute and chronic, each of which has unique etiologies, pathologies, and therapies.

Causes, incidence, and risk factors

Bronchitis occurs most often during the cold and flu season, usually coupled with an upper respiratory infection.

* Several viruses cause bronchitis, including influenza A and B, commonly referred to as "the flu."

* A number of bacteria are also known to cause bronchitis, such as Mycoplasma pneumoniae, which causes so-called "walking pneumonia"

* Bronchitis also can occur when a person inhales irritating fumes or dust. Chemical solvents and smoke, including tobacco smoke, have been linked to acute bronchitis

* People at increased risk both of getting bronchitis and of having more severe symptoms include the elderly, those with weakened immune systems, smokers, and anyone with repeated exposure to lung irritants

Acute bronchitis generally follows a viral respiratory infection. At first, it affects the nose, sinuses, and throat and then spreads to the lungs. Sometimes, another (secondary) bacterial infection is found in the airways. This means that bacteria have infected the airways, in addition to the virus.

People at risk for acute bronchitis include:

* The elderly, infants, and young children

* Persons with heart or lung disease

* Smokers

Chronic bronchitis is a long-term condition. To be diagnosed with chronic bronchitis, you must have a cough that produces excessive mucus most days of the month for at least 3 months.

Chronic bronchitis is one type of chronic obstructive pulmonary disease, or COPD for short. (Emphysema is another type of COPD.)

The following can make bronchitis worse:

* Air pollution

* Allergies

* Certain occupations (such as coal mining, textile manufacturing, or grain handling)

* Infections

Symptoms

Acute bronchitis most commonly occurs after an upper respiratory infection such as the common cold or a sinus infection. The affected person may have symptoms such as fever with chills, muscle aches, nasal congestion, and sore throat. The symptoms of either type of bronchitis may include:

* Chest discomfort

* Cough that produces mucus; if it's yellow-green, you are more likely to have a bacterial infection

* Fatigue

* Fever -- usually low

* Shortness of breath worsened by exertion or mild activity

* Wheezing, even after acute bronchitis has cleared, a dry, nagging cough may linger for several weeks

Additional symptoms of chronic bronchitis include:

* Ankle, feet, and leg swelling

* Blue-colored lips from low levels of oxygen

* Frequent respiratory infections (such as colds or the flu)

A health care provider will listen to your lungs with a stethoscope. Abnormal sounds in the lungs called rales or other abnormal breathing sounds may be heard.

Tests may include:

Chest x-ray

Lung function tests provide information that is useful for diagnosis and your outlook.

Pulse oximetry helps determine the amount of oxygen in your blood. This quick and painless test uses a device that is placed onto the end of your finger

* Arterial blood gas is a more exact measurement of oxygen and carbon dioxide levels, but it requires a needle stick and is more painful

Sputum samples may be taken to check for signs of inflammation or bacterial infection