Bronchitis, an inflammation of the lung's air passages, can be caused by several viruses. Viral bronchitis is often caused by the influenza virus or as a complication from a common cold virus. Bronchitis resulting from viral infections is more prevalent in the cold and flu season of the winter months. Up to 90 percent of the cases of acute bronchitis are caused by a virus, with the remaining 10 percent occurring from a bacterial infection.
When a viral infection attacks the bronchial tubes (the large air passages of the lungs) the tubes respond to the attack by becoming inflamed, producing mucus and swelling. These passages narrow and may even close, making breathing difficult. The mucus produced as a response to the viral attack builds up in the passageways and the body attempts to remove this mucus by coughing. Often viral bronchitis occurs during a bout of the flu or after a cold.
A bronchitis infection always includes a cough, but the symptoms that accompany the cough may vary. Frequently, the cough of viral bronchitis is associated with large amounts of dark yellow or green mucus. Additional symptoms of viral bronchitis may include chest congestion, fever, fatigue, chills, sinus congestion, wheezing, sore throat or aching in the chest.
Viral bronchitis is typically diagnosed based on the patient's symptoms. Inflammation of the bronchial tubes can be confirmed by listening to the chest with a stethoscope. A chest X-ray may also be performed to rule out the possibility of pneumonia. In some cases, a sputum sample is collected to determine whether the bronchitis is caused by a virus or bacteria.
Viral bronchitis is treated with rest and nonprescription cough medications. If the cough is severe, a prescription cough suppressant, expectorant or inhaler may be prescribed. Because antibiotics are ineffective against viral infections, they are not used to treat viral bronchitis. The risk of contracting viral bronchitis can be reduced by obtaining a flu vaccination, avoiding cigarettes and by washing hands frequently during cold and flu season.
Several things can be done at home to ease the symptoms of viral bronchitis. Warm steam from a vaporizer or hot shower can loosen phlegm, making the cough more productive. Medications to reduce fever can help with associated discomfort. A cough suppressant should not be used to treat viral bronchitis as the cough from the illness helps get rid of excess mucus in the lungs.