Bronchitis
Bronchitis is inflammation of the bronchi in the lungs that causes coughing. This condition usually begins as an infection in the nose, ears, throat, or sinuses before moving down to the airways. Symptoms include coughing up sputum, wheezing, shortness of breath, and chest pain. The disease presents in two distinct forms: acute and chronic. Acute bronchitis typically features a cough lasting around three weeks and is often called a chest cold. In more than 90% of cases, this form stems from a viral infection spread through the air or direct contact. A small number of acute cases arise from bacteria like Mycoplasma pneumoniae or Bordetella pertussis. Chronic bronchitis carries a stricter definition requiring a productive cough for three months or more per year for at least two years. Many people with chronic bronchitis also have chronic obstructive pulmonary disease known as COPD.
Chronic bronchitis is marked by mucus hypersecretion and mucins that thicken airway secretions. The excess mucus is produced by an increased number of goblet cells and enlarged submucosal glands in response to long-term irritation. Mucous glands in the submucosa secrete more than the goblet cells do. Mucins thicken mucus, and their concentration has been found to be high in cases of chronic bronchitis. This correlates with the severity of the disease. Excess mucus can narrow the airways, thereby limiting airflow and accelerating the decline in lung function. In COPD, those with the chronic bronchitic phenotype experience a worse quality of life than those without. The cough is often worse soon after awakening, and the sputum may have a yellow or green color. Effective mucociliary clearance depends on airway hydration, ciliary beating, and rates of mucin secretion, all of which are impaired in this condition.
Most cases of chronic bronchitis are caused by tobacco smoking. Chronic bronchitis in young adults who smoke is associated with a greater chance of developing COPD. There is an association between smoking cannabis and chronic bronchitis as well. Chronic inhalation of air pollution or irritating fumes from hazardous exposures in occupations like coal mining, grain handling, textile manufacturing, livestock farming, and metal moulding also serves as a risk factor. Bronchitis caused in this way is often referred to as industrial bronchitis or occupational bronchitis. Air quality affects the respiratory system with higher levels of nitrogen dioxide and sulfur dioxide contributing to bronchial symptoms. Sulfur dioxide can cause inflammation which aggravates chronic bronchitis and makes infections more likely. While the primary risk factor for chronic bronchitis is smoking, there is still a 4, 22% chance that non-smokers can get the disease due to other factors.
Diagnosis is typically based on a person's signs and symptoms rather than specific laboratory testing. A common sign of bronchitis is a cough lasting ten days to three weeks. If the cough lasts longer than a month, it may become chronic bronchitis. Other causes of similar symptoms include asthma, pneumonia, bronchiolitis, bronchiectasis, and COPD. A chest X-ray may be useful to detect pneumonia but is not always required. The color of the sputum does not indicate if the infection is viral or bacterial. Determining the underlying organism is usually not required. No specific testing is normally needed to diagnose acute bronchitis. In children, protracted bacterial bronchitis is defined as a chronic productive cough with a positive bronchoalveolar lavage that resolves with antibiotics.
One form of prevention is to avoid smoking and other lung irritants. Frequent hand washing may also be protective. Treatment for acute bronchitis usually involves rest, paracetamol, and NSAIDs to help with the fever. Cough medicine has little support for its use and is not recommended in children under the age of six. There is tentative evidence that salbutamol may be useful in treating wheezing though it may result in nervousness and tremors. Antibiotics should generally not be used except when due to pertussis. Getting plenty of rest and drinking enough fluids are often recommended as well. Decline in lung function in chronic bronchitis may be slowed by stopping smoking. Chronic bronchitis may be treated with medications including mucolytics like guaifenesin which lasts for twelve hours. Pulmonary rehabilitation may also be used to manage symptoms.
The British physician Charles Badham was the first person to describe the condition and name the acute form as acute bronchitis in his book Observations on the inflammatory affections of the mucous membrane of the bronchiæ published in 1808. In this book, Badham distinguished three forms of bronchitis including acute and chronic. A second expanded edition of the book was published in 1814 with the title An essay on bronchitis. Badham used the term catarrh to refer to the cardinal symptoms of chronic cough and mucus hypersecretion. He described chronic bronchitis as a disabling disorder. In 1953 findings from a joint research programme undertaken in Chicago and London were published in the Lancet. It stated that since its introduction by Badham, chronic bronchitis had become an increasingly popular diagnosis. A CIBA meeting in 1959 and a meeting of the American Thoracic Society in 1962 defined chronic bronchitis as a component of COPD in terms that have not changed.
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Common questions
What is bronchitis and how does it begin?
Bronchitis is inflammation of the bronchi in the lungs that causes coughing. This condition usually begins as an infection in the nose, ears, throat, or sinuses before moving down to the airways.
How long does acute bronchitis last and what causes most cases?
Acute bronchitis typically features a cough lasting around three weeks and is often called a chest cold. In more than 90% of cases, this form stems from a viral infection spread through the air or direct contact.
What are the diagnostic criteria for chronic bronchitis?
Chronic bronchitis carries a stricter definition requiring a productive cough for three months or more per year for at least two years. Many people with chronic bronchitis also have chronic obstructive pulmonary disease known as COPD.
Who first described acute bronchitis and when was it published?
The British physician Charles Badham was the first person to describe the condition and name the acute form as acute bronchitis in his book Observations on the inflammatory affections of the mucous membrane of the bronchiæ published in 1808.
What are the main risk factors for developing chronic bronchitis?
Most cases of chronic bronchitis are caused by tobacco smoking. Chronic inhalation of air pollution or irritating fumes from hazardous exposures in occupations like coal mining, grain handling, textile manufacturing, livestock farming, and metal moulding also serves as a risk factor.