Bronchitis: Causes, Risk Factors, and Symptoms

Acute bronchitis is mainly caused by a viral infection, whereas cigarette smoking is the most common cause of chronic bronchitis.

Causes of acute bronchitis

Acute bronchitis can be caused viral and bacterial organisms. Out of all, the most common viruses responsible for acute bronchitis include influenza A and B, Respiratory syncytial virus and parainfluenza virus, rhinovirus and adenovirus. Bacterial causes of acute bronchitis include mycoplasma, streptococcus pneumoniae, chlamydia pneumoniae, Haemophilus influenza and Moraxella cattarhalis.

Exposure to irritant substances such as dust, chemical agents and the substances in tobacco smoke can also cause acute bronchitis.

Causes of Chronic bronchitis

Smoking is the number one cause of bronchitis. About 85% to 90% of the patients who smoke cigarettes develop chronic bronchitis and chronic obstructive pulmonary disease (COPD).

Other causes of chronic bronchitis include air pollution, exposure to dust and other irritants in the environment or at the work place.

Are you at risk of developing bronchitis?

• If you are a chronic smoker, then you are at a higher risk of catching bronchitis. The irritant substances in the smoke damage the lining cells of the air passages which ultimately lead to bronchitis.
• If you are suffering from a chronic condition, such as carcinoma, then your immune system is suppressed. This makes you more prone to develop bronchitis. Most often elderly people and infants have a low immunity and therefore are more vulnerable to develop bronchitis.
• If you are working at a textile company or if you work around grains, then you are more exposed to irritants. Long term exposure to these irritants will increase the chance of developing bronchitis.
• If you are a suffering from repeated episodes of gastric reflux (heart burn), the acids will damage the mucosa and predispose you to the development of bronchitis.

How will I know if I have bronchitis?

The signs and symptoms can help your doctor to suspect bronchitis along with a good detailed clinical history. The clinical features of bronchitis include:

• Cough – A cough lasting for more than five days is likely to be of acute bronchitis. This way you can easily differentiate an upper respiratory infection from bronchitis.

If you have acute bronchitis, the cough may last up to about one to three weeks, but if you are suffering from chronic bronchitis you may have the cough for more than three months and have similar episodes every year. If you are diagnosed with chronic bronchitis, it is also possible for you to have periods where the signs and symptoms are severe. At these times you may have an acute attack on top of chronic bronchitis.

• Sputum production – The sputum can be clear, white, yellow, green or sometimes streaked with blood. Yellow sputum often indicates that the cough is due to an infection.
• A low grade fever with chills.
• Runny nose.
• Muscle aches and pains.
• Headache.
• Sore throat.
• Generalized body weakness.
• Discomfort in the chest.
• Dyspnea on exertion – This is a late feature of bronchitis which is not usually observed in adults unless they have developed chronic obstructive pulmonary disease (COPD).
• Mild cyanosis of the mucous membranes – This is the blue discoloration of your mucous membranes such as your tongue. This is a feature of chronic obstructive pulmonary disease (COPD). You will get to this stage with time if you do not stop smoking.

During your physical exam, your doctor may identify the following signs:

• Localized lymphadenopathy – Enlarged lymph nodes which may become palpable during an infection.
• Use of accessory muscles for breathing – This suggests that you have difficulty in breathing and therefore needs to use extra force to inhale the normal amount of oxygen you need.
• Diffuse wheezes – These may be heard on auscultation of your chest.