Dear Doctors: I was recently sick with what I thought was the flu. I had a fever, sore throat and a terrible cough. I have asthma, so my husband insisted that I see our family doctor. She said that I did have the flu, but I also had acute bronchitis. Can you please explain what that is?
Dear Reader: Acute bronchitis is a respiratory tract infection that involves two of the major airways in the lungs. It is usually caused by a viral infection, and as happened with you, it can follow a case of the flu. Less often, a bacterial infection can be the cause. If left untreated, acute bronchitis can lead to more serious health problems, including pneumonia. People living with asthma and those who smoke have an increased risk of developing bronchitis during a respiratory illness.
To better understand the condition, we should begin with a bit of anatomy. When you breathe in, air enters through the nose or mouth and is directed into the trachea. Also referred to as the windpipe, this is the long, flexible tube that carries air toward the lungs. At its base, the trachea splits into two branches. These are the bronchi. (For fellow science nerds, each one is called a bronchus.) One of these branches leads to the left lung and the other to the right lung.
After the bronchi enter the lungs, they continue to divide into increasingly smaller and narrower branches, much like the canopy of a tree. At their smallest, now known as bronchioles, they connect to the more than 280 million tiny air sacs, or alveoli, located deep within each lung. These alveoli do the crucial work of delivering oxygen to the blood and receiving carbon dioxide, which is a waste product, to be exhaled.
When someone has bronchitis, it means that an infection of some kind has caused the inner lining of the bronchi to become inflamed. The immune system increases the production of mucus in the bronchi in an effort to trap and clear out the invading microbes, leading to the primary symptom of bronchitis. This is a deep, hacking cough, which typically brings up thick phlegm. It may range in color from clear to yellow to greenish.
People with bronchitis may feel short of breath and hear a wheezing sound as they breathe. Lingering irritation can cause continued coughing for several weeks after the initial infection has cleared. Because the increase in mucus production can decrease the amount of oxygen delivered to the blood by the alveoli, people with bronchitis often feel fatigue and tire easily during exertion. Additional symptoms of this illness are similar to those of other upper respiratory tract infections. They include fever, headache, body aches, chills and a sore throat.
Treatment focuses on management of symptoms. This includes medications to ease cough and physical discomfort and to lower fever. Expectorants, which thin out mucus and make it easier to expel, may be prescribed. It is important to stay hydrated, get plenty of rest and not overdo it when you return to your daily routine.
(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
