Acute bronchitis is an inflammation of the lining of the bronchi of lungs. It is a very common presentation in an emergency department, urgent care center, and primary care office. About 5% of adults have an episode of acute bronchitis each year. An estimated 90% of these seek medical advice for the same. In the United States, acute bronchitis is among the top ten most common illness among outpatients. Acute bronchitis typically lasts ten to 20 days (median in a study was 18 days) but can last for more than 4 weeks.
Acute bronchitis is most commonly due to viruses and is usually self-limiting. Approximately 95% of acute bronchitis in healthy adults are secondary to viruses. It can sometimes be caused by allergens, irritants, and bacteria. Irritants include smoke inhalation, polluted air inhalation, dust, among others.
Like most of the viral diseases of the respiratory tract, acute bronchitis is most commonly seen during the flu season. In the United States, flu season is most common during autumn and winter. It can follow any viral upper respiratory infection (URI). The common pathogens are a respiratory syncytial virus, Influenza virus A and B, Parainfluenza, rhinovirus, and similar viruses.
Factor like a history of smoking, living in a polluted place, crowding, and a history of asthma, are all risk factors for acute bronchitis. In some people, acute bronchitis can be triggered by particular allergens like pollens, perfume, and vapors.
When the infection is bacterial, the isolated pathogens are usually the same as those responsible for community-acquired pneumonia, for example, Streptococcus pneumonia and Staphylococcus aureus.
Sometimes when a person suffers from URI, the inflammation reaches down to bronchi, causing acute inflammation of bronchi, and the result is bronchitis. Sometimes allergens and pollutants can cause similar inflammation as well. Rarely, in healthy adults, and more often in immunocompromised adults or an at-risk population, this inflammation may be due to a bacterial pathogen.
An acute bronchitis patient presents with a productive cough, malaise, difficulty breathing, and wheezing. Usually, their cough is clear or yellowish, although sometimes it can be purulent. The symptoms may have been preceded by URI symptoms of a runny nose, sore throat, fever, and malaise. A low-grade fever may be present as well. Having high fevers in the setting of acute bronchitis is unusual.
On physical exam, lungs may have wheezing and some rhonchi. Tachycardia can be present reflecting fever as well as dehydration secondary to the viral illness. Rest of the systems are typically within normal limits.
Usually, acute bronchitis is a clinical diagnosis based on history, past medical history, lung exam, and other physical findings. Oxygen saturation plays an important role in judging the severity of the disease along with the pulse rate, temperature, and respiratory rate. In more severe cases a more detailed pulmonary function assessment may be warranted, including forced expiratory volume testing.
A chest x-ray may be needed to differentiate from pneumonia. In cases of acute bronchitis, there is no definitive chest x-ray finding, and it is typically read as normal. Sometimes it can reflect changes of reactive airway disease. However, infiltrates are not seen.
Complete blood count and chemistry may be ordered as workup for fever. White blood count might be mildly elevated in some cases of acute bronchitis. Blood chemistry can reflect dehydration changes.
If there are a persistent cough and hypoxia and the history does not point towards a viral illness or reactive airway disease, then other pathologies like pulmonary emboli should be considered.
Treatment of acute bronchitis is typically symptomatic control and supportive therapy. Analgesic and antipyretic agents may be used to treat associated malaise, myalgia, and fever. Nebulizer and inhalers can be given to help with reactive airway resulting from inflammation. They can help relieve bronchospasm and wheezing. Prednisone or other steroids can be given to help with the inflammation as well. Although there is not enough evidence showing their benefit, it is useful in patients with underlying chronic obstructive pulmonary disease (COPD) or asthma. Typically steroid is used as short-term burst therapy. Sometimes longer tapering dose of steroid might be warranted, especially in patients with underlying asthma or COPD. Cough relief can be provided using cough suppressants like benzoate and codeine. A mucolytic can be used to clear mucus and avoid plugging. If there is an allergic component, then an anti-allergenic can help relieve symptoms. Humidifier use can also achieve symptomatic relief.
Antibiotic is typically not indicated for simple acute bronchitis in otherwise healthy adults. It should be used only in cases where chances of bacterial bronchitis are high or at special risk populations. Procalcitonin might be useful in deciding on antibiotic use. A Cochrane review of nine randomized, controlled trials of antibiotic agents showed a minor reduction in the total duration of a cough (0.6 days). The decrease in the number of days of illness was not significant per this review. Hence antibiotic use should be avoided in simple cases considering the cost of antibiotic, the growing global problem of antibiotic resistance and the possible side effects of antibiotic usage.
Lifestyle modification like smoking cessation and the avoidance of allergens and pollutants play an important role in avoidance of recurrence and complications. Flu vaccine and pneumonia vaccine are especially recommended in special groups including adults older than 65, children younger than two years (older than six months), pregnant women, and residents of nursing homes and long-term care facilities. People with asthma, COPD, and other immunocompromised adults are also at higher risk of developing complications. Recurrence is seen in up to a third of the cases of acute bronchitis.
Data for the use of beta-agonist, steroids, and mucolytic agent, especially in patients with no underlying COPD and asthma, is lacking. Treatment should be guided by the individual response to them and reported benefit, as well as, weighing risk and benefit in each case.
Sometimes secondary pneumonia can develop. This is usually indicated by worsening symptoms, productive cough and fever. In such cases, a chest x-ray is indicated. This is especially important in immunocompromised adults, elderly population, infants and newborns, and smokers. Pulmonary emboli should always be in differentials in a patient with a cough and shortness of breath. Sometimes aggressive coughing can lead to spontaneous pneumothorax and or spontaneous pneumomediastinum. Hence any acute worsening of symptoms usually requires a chest x-ray.
A multidisciplinary approach to acute bronchitis
Acute bronchitis is a very common disorder that frequently presents to the emergency department or the primary provider's office. It is a very common cause of absenteeism from work/school. The condition is best managed by a multidisciplinary team that includes a primary care provider, nurse, a pharmacist, and a pulmonologist. The key is patient education. Patients should be urged to stop smoking and avoid exposure to secondhand smoke. These individuals should get the influenza and pneumococcal vaccines to reduce the morbidity. In addition, the nurse and pharmacist should encourage hand washing to limit the spread of micro-organisms.
The outcomes of patients with acute bronchitis are good; however, it is a common reason for absenteeism from work. In some patients with underlying COPD and other lung problems, acute bronchitis can have a high morbidity. Patients whose symptoms persist for more than six weeks need to be re-evaluated to ensure that the diagnosis is correct. (Level V)