Acute bronchitis is a very common respiratory disease that generates symptoms such as mucus-producing cough, chest discomfort and pain, difficult and shallow breathing, wheezing and fever. One of the most commonly diagnosed respiratory diseases in the United States, acute bronchitis is responsible for causing an estimated 2.5 million new cases of breathing insufficiency each year. Although it has the highest incidence in people with ages over 50, acute bronchitis can be seen in young adults and children as well.

Acute bronchitis refers to inflammation of the bronchial mucosal membranes, triggered by various external irritant or infectious agents. Due to prolonged exposure to irritants, pollutants or due to infection with viruses or bacteria, the bronchial region becomes inflamed, resulting in overproduction and expectoration of mucus. Mucus is a substance produced by the soft tissues and membranes involved in breathing. It has a very important role in protecting the respiratory tract against irritants and infectious organisms. However, in the case of acute bronchitis, overproduction of mucus is an inflammatory reaction of the respiratory tract due to irritation of the bronchia. An excessive production of mucus leads to obstruction of the airways, causing wheezing and shallow, accelerated, difficult breathing.

There is a wide range of factors that can lead to the occurrence of acute bronchitis. The most common cause of acute bronchitis is infection with viruses. The viral organisms responsible for triggering the manifestations of acute bronchitis are: adenovirus, influenza virus, parainfluenza virus, coronavirus, coxsackievirus, enterovirus, rhinovirus and respiratory syncytial virus. Commonly developed by children, viral forms of acute bronchitis are usually less serious and generate milder symptoms (mild to moderate fever, non-severe cough and less pronounced obstruction of the airways).

Acute bronchitis can also be the consequence of bacterial infections. Common bacterial agents responsible for causing acute bronchitis are: Streptococcus pneumoniae, Haemophilus influenzae, Bordatella pertussis, Bordatella parapertussis and Branhamella catarrhalis. In some cases, the disease can also be triggered by mycoplasmas, infectious organisms that share the characteristics of both viruses and bacteria. When acute bronchitis is caused by infection with mycoplasmas, the disease is usually severe, has a rapid onset and generates very pronounced symptoms. Some forms of mycoplasma bronchitis can even be life-threatening. Common atypical bacterial agents (mycoplasmas) responsible for causing acute bronchitis are: Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella.

Sometimes, acute bronchitis can also be caused by infection with fungal organisms such as Candida albicans, Candida tropicalis, Blastomyces dermatitidis, Histoplasma capsulatum and Coccidioides immitis. When acute bronchitis is the result of bronchial infection with fungal elements, the disease is generally less serious and generates mild to moderate symptoms.

Non-infectious factors that can lead to the occurrence of acute bronchitis are: dust, pollen, chemicals, pollutants, cigarette smoke, substances with strong, irritant odor (alcohol, paints, benzene). When acute bronchitis is solely the result of exposure to non-infectious irritant agents, the disease is usually less severe and generates mild to moderate symptoms. In this case, the medical treatment is focused towards alleviating the clinical manifestations of the disease. Patients are usually prescribed bronchodilators or cough suppressants for decongestion of the airways and rapid symptomatic relief.