Table of Contents
Definition of Bronchitis
INFLAMMATION of the bronchi, the airways that branch from the TRACHEA into the LUNGS. Bronchitis may be viral, bacterial, or the result of irritation such as cigarette smoking or exposure to environmental pollutants. It may also occur as an acute condition that comes on suddenly, runs its course, and heals without lasting damage or persistently recur as a chronic condition.
Acute infectious bronchitis is especially common during the “cold and flu” season, when it typically follows a viral INFECTION of the upper respiratory tract. Numerous viruses may be responsible, including ADENOVIRUS, coronaviruses, INFLUENZA viruses, and rhinoviruses. Acute viral bronchitis generally runs its course over a period of five to seven days, during which the person feels and appears ill. A residual COUGH may persist for several weeks after the infection subsides.
Acute irritative bronchitis develops in response to inhaled irritants such as fumes, dust, and smoke (cigarette as well as environmental). Symptoms may be difficult to distinguish from those of ASTHMA, particularly in people who do not have a diagnosis of asthma or who have infrequent asthma attacks. The inhaled substance irritates the lining of the bronchi, causing localized inflammation. Most often, the inflammation and resulting bronchitis subsides over the course of a few days.
Repeated exposure to irritants such as cigarette smoke, occupational chemicals, and environmental pollutants may cause persistent or recurrent bronchial inflammation. By far the most common culprit is cigarette smoking or environmental cigarette smoke exposure (second-hand smoking). The hallmark symptom is persistent, productive cough that continues for three months or longer.
Over time, chronic bronchitis may evolve into CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) or BRONCHIECTASIS, two conditions in which damage to the bronchi is extensive and permanent. People who have chronic bronchitis are more vulnerable to bacterial infections such as PNEUMONIA, as well as to complications such as ATELECTASIS (collapse of a bronchial segment).
Symptoms and Diagnostic Path
The symptoms of acute bronchitis include FEVER, productive cough, sore THROAT, and chest discomfort or PAIN, especially when taking a deep breath. SPUTUM that is thick, yellowish green, and foulsmelling suggests bacterial infection. Red or brown streaks in the sputum indicate bleeding, which may be from the irritation of coughing or signal a different diagnosis.
The diagnostic path includes AUSCULTATION to listen to BREATH SOUNDS, which are typically normal. The doctor may request a chest X-RAY to rule out other causes of the symptoms. The doctor may also collect a sputum sample for culture if there is any suspicion the infection could be bacterial.
The primary symptoms of chronic bronchitis are productive cough and DYSPNEA (shortness of breath). Physical exertion tends to exacerbate both. The diagnostic path begins with auscultation, which may reveal abnormalities of breath sounds depending on whether there is damage to the bronchial structures. Chest X-ray may show areas of inflammation as well as atelectasis or bronchiectasis if either is present. The doctor is likely to conduct further diagnostic procedures to rule out other conditions that could cause similar symptoms, such as asthma or, especially in smokers, LUNG CANCER.
Treatment Options and Outlook
Treatment for acute viral bronchitis is primarily supportive and targets symptom relief. The doctor may recommend a cough suppressant or an OVERTHE-COUNTER (OTC) DRUG such as acetaminophen to relieve fever and discomfort. It is important to drink lots of fluids to maintain HYDRATION and to thin bronchial secretions. When fever persists or recurs after acute infectious bronchitis, the likelihood of bacterial infection is high in which case treatment with ANTIBIOTIC MEDICATIONS becomes necessary.
Antibiotics are not helpful for viral bronchitis, however. The doctor may prescribe an inhaled corticosteroid medication to suppress the inflammatory response in acute irritative bronchitis. Bronchodilators may also help if the bronchitis causes bronchospasm and wheezing.
The most effective treatment for chronic bronchitis is removing the cause of the symptoms, which most often is cigarette smoking. Chronic bronchitis becomes inevitable at some point in everyone who smokes. People who work in environments with high exposures to fumes, dust, or pollutants should use appropriate protective gear including masks or respirators. Chronic bronchitis that continues unchecked results in permanent damage to the bronchial structures.
Risk Factors and Preventive Measures
Frequent HAND WASHING is the best defense against viral infections of any sort. Upper respiratory viruses spread through droplet contamination, which may occur through direct touch (such as shaking hands) or breathing droplets coughed or sneezed into the air by those who have upper respiratory viruses. In epidemic circumstances, doctors may prescribe antiviral medications such as rimantadine to reduce the risk or severity of infection.
Removal from the source of irritation reduces symptoms to improve chronic bronchitis. People who have high risk of respiratory infection, such as those who have chronic lung disease or other chronic health conditions, should receive influenza vaccination (flu shot) every year and pneumonia vaccination every five years.