Bronchitis

From Wikipedia, the free encyclopedia

Bronchitis
Figure A shows the location of the lungs and bronchial tubes. Figure B is an enlarged view of a normal bronchial tube. Figure C is an enlarged view of a bronchial tube with bronchitis.
Pronunciation	bron-kye-tis
Specialty	Infectious disease, pulmonology
Symptoms	Coughing up mucus, wheezing, shortness of breath, chest discomfort
Types	Acute, chronic
Frequency	Acute: ~5% of people a year Chronic: ~5% of people

Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Symptoms include coughing up sputum, wheezing, shortness of breath, and chest pain. Bronchitis can be acute or chronic.

Acute bronchitis usually has a cough that lasts around three weeks, and is also known as a chest cold. In more than 90% of cases the cause is a viral infection. These viruses may be spread through the air when people cough or by direct contact. A small number of cases are caused by a bacterial infection such as Mycoplasma pneumoniae or Bordetella pertussis. Risk factors include exposure to tobacco smoke, dust, and other air pollution. Treatment of acute bronchitis typically involves rest, paracetamol (acetaminophen), and nonsteroidal anti-inflammatory drugs (NSAIDs) to help with the fever.

Chronic bronchitis is defined as a productive cough – one that produces sputum – that lasts for three months or more per year for at least two years. Most people with chronic bronchitis have chronic obstructive pulmonary disease (COPD). Tobacco smoking is the most common cause, with a number of other factors such as air pollution and genetics playing a smaller role. Treatments include quitting smoking, vaccinations, rehabilitation, and often inhaled bronchodilators and steroids. Some people may benefit from long-term oxygen therapy.

Acute bronchitis is one of the most common diseases. About 5% of adults are affected and about 6% of children have at least one episode a year. Acute bronchitis is the most common type of bronchitis. In the United States, in 2016, 8.6 million people were diagnosed with chronic bronchitis.

Acute bronchitis

Bronchitis

Acute bronchitis, also known as a chest cold, is short term inflammation of the bronchi of the lungs. The most common symptom is a cough, that may or may not produce sputum. Other symptoms include coughing up mucus, wheezing, shortness of breath, fever, and chest discomfort. The infection may last from a few to ten days. The cough may persist for several weeks afterwards, with the total duration of symptoms usually around three weeks. Symptoms may last for up to six weeks.

Cause

In more than 90% of cases, the cause is a viral infection. These viruses may spread through the air when people cough or by direct contact. Risk factors include exposure to tobacco smoke, dust, and other air pollutants. A small number of cases are due to high levels of air pollution or to bacteria such as Mycoplasma pneumoniae or Bordetella pertussis.

Diagnosis

Diagnosis is typically based on a person's signs and symptoms. The color of the sputum does not indicate if the infection is viral or bacterial. Determining the underlying organism is usually not required. Other causes of similar symptoms include asthma, pneumonia, bronchiolitis, bronchiectasis, and COPD. A chest X-ray may be useful to detect pneumonia.

Another common sign of bronchitis is a cough which lasts ten days to three weeks. If the cough lasts a month or a year, it may become chronic bronchitis. In addition, a fever may be present. Acute bronchitis is normally caused by a viral infection. Typically, these infections are rhinovirus, parainfluenza, or influenza. No specific testing is normally needed in order to diagnose acute bronchitis.

Treatment

Prevention is by not smoking and avoiding other lung irritants. Frequent hand washing may also be protective. Treatment for acute bronchitis usually involves rest, paracetamol (acetaminophen), 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; however, it may result in nervousness and tremors. Antibiotics should generally not be used. An exception is when acute bronchitis is due to pertussis. Tentative evidence supports honey and pelargonium to help with symptoms. Getting plenty of rest and drinking enough fluids are often recommended as well.

Epidemiology

Acute bronchitis is one of the most-common diseases. About 5% of adults are affected, and about 6% of children have at least one episode a year. It occurs more often in the winter. More than 10 million people in the US visit a doctor each year for this condition, with about 70% receiving antibiotics which are mostly not needed. There are efforts to decrease the use of antibiotics in acute bronchitis. Acute bronchitis is the most common type of bronchitis.

Chronic bronchitis

When bronchitis, marked by a productive cough, occurs for longer than three months, in two consecutive years, it is classed as chronic bronchitis. When this occurs together with decreased airflow it is known as chronic obstructive pulmonary disease (COPD) or chronic obstructive bronchitis. Most people with chronic bronchitis have COPD however most people with COPD do not have chronic bronchitis. Previously the term "chronic bronchitis" was also used for a type of COPD. Chronic bronchitis is a respiratory tract disease marked by mucus hypersecretion. The cough is often worse soon after awakening, and the sputum produced may have a yellow or green color and may be streaked with specks of blood. The ICD-11 lists chronic bronchitis with emphysema (emphysematous bronchitis) as a "certain specified COPD".

Cause

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. In addition, chronic inhalation of air pollution or irritating fumes or dust from hazardous exposures in occupations such as coal mining, grain handling, textile manufacturing, livestock farming, and metal moulding may also be a risk factor for the development of chronic bronchitis. Bronchitis caused in this way is often referred to as industrial bronchitis. Rarely genetic factors also play a role.

Treatment

Decline in lung function in chronic bronchitis may be slowed by stopping smoking. Chronic bronchitis is treated symptomatically and may be treated with or without medications. Nonpharmacologic approaches may include pulmonary rehabilitation, and oxygen therapy.

A distinction has been made between exacerbations (sudden worsenings) of chronic bronchitis, and otherwise stable chronic bronchitis. A Cochrane review found that mucolytics in chronic bronchitis may slightly decrease the chance of the developing an acute exacerbation. The mucolytic guaifenesin is a safe and effective treatment for stable chronic bronchitis. This has an advantage in that it is available as an extended use tablet which lasts for twelve hours. Erdosteine has been found to be effective in promoting the discharge of mucus and improving lung function in the elderly. Another mucolytic Fudosteine works by inhibiting MUC5AC expression, reducing the secretion of mucin.

In those with chronic bronchitis and severe COPD, the phosphodiesterase-4 inhibitor roflumilast may decrease significant exacerbations.

Epidemiology

Chronic bronchitis affects about 3.4% to 22% of the general population. Individuals over age 45 years of age, smokers, those that live or work in areas with high air pollution, and anybody with asthma all have a higher risk of developing chronic bronchitis. This wide range is due to the different definitions of chronic bronchitis that can be diagnosed based on signs and symptoms or the clinical diagnosis of the disorder. Chronic bronchitis tends to affect men more often than women. While the primary risk factor for chronic bronchitis is smoking, there is still a 4%-22% chance that never smokers can get chronic bronchitis. This might suggest other risk factors such as the inhalation of fuels, dusts, fumes and genetic factor. In the United States, in 2016, 8.6 million people were diagnosed with chronic bronchitis, and there were 518 reported deaths. Per 100,000 of population the death rate of chronic bronchitis was 0.2.