Bronchitis causes

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]; Nate Michalak, B.A.

Overview[edit | edit source]

Virus are thought to be the most common cause of acute bronchitis. Influenza A and B, parainfluenza, respiratory syncytial virus, coronavirus are the most commonly involved pathogens. Bacteria, such as mycoplasma, chlamydiae and bordetella pertussis, are also found to cause acute bronchitis. Smoking, occupational exposures, air pollutants, and genetic factors are etiologies of chronic bronchitis.

Causes[edit | edit source]

• Acute Bronchitis: may be caused by either viruses, bacteria or environmental factors.

Viruses: Influenza virus, parainfluenza virus, respiratory syncytial virus, coronavirus, adenovirus, enterovirus, rhinovirus, coxsackievirus, and human metapneumovirus^[1][2][3]

Bacteria: Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Bordetella pertussis^[4]

Environmental factors: Toxic fume inhalation, tobacco, dust, and aerosols^[5]

• Chronic Bronchitis: may be caused by smoking, air pollutants, occupational exposures, and genetic factors

Smoking

The primary risk factor for COPD is chronic tobacco smoking. In the United States, 80 to 90% of cases of COPD are due to smoking.^[6][7] Exposure to cigarette smoke is measured in pack-years, the average number of packages of cigarettes smoked daily multiplied by the number of years of smoking.^[8] The likelihood of developing COPD increases with age and cumulative smoke exposure. Almost all life-long smokers will develop COPD.^[9]

Occupational Exposures

Intense and prolonged exposure to workplace dusts found in coal mining, gold mining, and the cotton textile industry, and chemicals such as cadmium, isocyanates, and fumes from welding, have been implicated in the development of airflow obstruction, even in nonsmokers.^[10] Workers who smoke and are exposed to these particles and gases are even more likely to develop COPD. Intense silica dust exposure causes silicosis, a restrictive lung disease distinct from COPD; however, less intense silica dust exposures have been linked to a COPD-like condition.^[11] The effect of occupational pollutants on the lungs appears to be substantially less important than the effect of cigarette smoking.^[12]

Air Pollution

Studies in many countries reveal that people who live in large cities have a higher rate of COPD compared to people who live in rural areas.^[13] Urban air pollution may be a contributing factor for COPD, as it is thought to slow the normal growth of the lungs, although the long-term research needed to confirm the link has not been performed. Studies of the industrial waste gas and COPD/asthma-aggravating compound, sulfur dioxide, and the inverse relation to the presence of the blue lichen Xanthoria (usually found abundantly in the countryside, but never in towns or cities) suggest that combustive industrial processes do not aid COPD sufferers. In many developing countries, indoor air pollution from cooking fire smoke (often using biomass fuels such as wood and animal dung) is a common cause of COPD, especially in women.^[14]

Genetics

Some factor in addition to heavy smoke exposure is required for a person to develop COPD. This factor is probably a genetic susceptibility. COPD is more common among relatives of COPD patients who smoke than unrelated smokers.^[15] The genetic differences that make some peoples' lungs susceptible to the effects of tobacco smoke are mostly unknown. Alpha 1-antitrypsin deficiency is a genetic condition that is responsible for approximately 2% of cases of COPD. In this condition, the body does not make enough of the protein alpha 1-antitrypsin. Alpha 1-antitrypsin protects the lungs from damage caused by protease enzymes, such as elastase and trypsin, that can be released as a result of an inflammatory response to tobacco smoke.^[16]

Common Causes[edit | edit source]

• Adenovirus
• Air pollution
• Bordetella pertussis
• Coal dust
• Coronavirus
• Influenza
• Mycoplasma pneumoniae
• Parainfluenza
• Respiratory syncytial virus
• Rhinovirus
• Tobacco smoking

Causes by Organ System[edit | edit source]

Causes in Alphabetical Order[edit | edit source]

Causes Based on Classification[edit | edit source]

Acute Bronchitis[edit | edit source]

• The cause of acute bronchitis depends on several factors including season of the year (winter and fall), vaccination level, age and immune status of the patient.
• Viruses are considered to be the most common cause of acute bronchitis. Common viruses include influenza A and B, parainfluenza, respiratory syncytial virus, coronavirus, adenovirus and rhinovirus.
• Human metapneumovirus is also found to cause bronchitis.
• Some atypical bacteria are also found to act as causative factors for bronchitis namely bordetella pertussis, Chlamydia pneumonia and mycoplasma pneumonia.

The following factors exacerbate bronchitis:

• Air pollution
• Allergens
• Certain occupations (such as coal mining, textile manufacturing, or grain handling)

Chronic Bronchitis[edit | edit source]

Chronic bronchitis is a long-term condition. People have a cough that produces excessive mucus. To be diagnosed with chronic bronchitis, a patient must have a cough with mucus most days of the month for at least 3 months.

References[edit | edit source]

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