Cough is generally the most common symptom observed amongst patients. It starts early in the course of many acute respiratory tract infections and goes on to become prominent as the disease continues to develop. It is often difficult to distinguish between upper respiratory infection and acute bronchitis within the first few days but cough lasting more than 5 days may suggest acute bronchitis [6].

In patients with acute bronchitis, cough generally lasts from 10-20 days. Sputum production is reported in more than 50% of individuals that present cough as symptom. The sputum may be green, yellow, clear or even blood tinged. In 50% of acute bronchitis cases, purulent sputum is reported. These changes in colour in the sputum is as a result of peroxidase released by leukocytes in sputum and this is why colour alone is not to be considered indicative of bacterial infection.

Fever is an unusual presentation and if this comes with the cough, pneumonia or influenza is often the case. Also, diarrhea, vomiting and nausea are rare. In severe cases, general malaise and chest pain may be presented. When there is severe involvement of the trachea, substernal chest pain association with respiration, coughing and burning will be presented.

Unless the patient has underlying chronic obstructive pulmonary disease or another condition that impairs lung function dyspnea and cyanosis are not observed especially in adults.

Other symptoms of bronchitis include extreme fatigue, muscle aches, headache, runny or stuffy nose and sore throat [7].

Bronchitis may be suspected in patients with an acute respiratory infection with cough; yet, because many more serious diseases of the lower respiratory tract cause cough, bronchitis must be considered a diagnosis of exclusion. A complete blood count with differential may be obtained.

Procalcitonin levels may be useful to distinguish bacterial infections from nonbacterial infections. Studies have shown that they may help guide therapy and reduce the use of antibioics.
If the cough is persistent sputum cytology may be helpful.

Chest radiography should be performed in those patients whose physical examination findings suggest pneumonia. Elderly patients may have no signs of pneumonia; therefore, chest radiography may be warranted in these patients, even without other clinical signs of infection [8].

Bronchoscopy may be needed to exclude foreign body aspiration, tuberculosis, tumors, and other chronic diseases of the tracheobronchial tree and lungs.

Therapy is generally focused on alleviation of symptoms. Toward this goal, a doctor may prescribe a combination of medications that open obstructed bronchial airways and thin obstructive mucus so that it can be coughed up more easily. Care for acute bronchitis is primarily supportive and should ensure that the patient is oxygenating adequately. Bed rest is recommended [9].

The most effective means for controlling cough and sputum production in patients with chronic bronchitis is the avoidance of environmental irritants, especially cigarette smoke.

Prognosis is positive for most bronchitis cases [5]. It may result in absenteeism from work and school but it is generally self-limiting in individuals who are otherwise healthy. Severe cases however may produce deterioration in patients with significant underlying cardiopulmonary disease.

The most common causes of acute bronchitis are respiratory viruses while cigarette smoking is undoubtedly the chief cause of chronic bronchitis.

The most common viral causes of acute bronchitis are influenza A and B virus, parainfluenza, coronavirus and respiratory syncytial virus. However, an etiologic agent is identified in very few cases. Acute bronchitis is also caused by infections like those caused by Haemophilus influenza, catarrhalis, Moraxella, Streptococcus pneumonia, Chlamydia pneumonia and the Mycoplasma species. Exposure to irritants like pollution, chemicals and tobacco smoke can also bring about acute bronchial irritation. 70-80% of acute exacerbations of chronic bronchitis arise from respiratory infections.

For chronic bronchitis, cigarette smoking is the major cause [2] [3]. The risk factors that are common for acute exacerbations of chronic bronchitis include low forced expiratory volume in one second and old age. For chronic bronchitis and chronic obstructive pulmonary disease, cigarette smoking is responsible for about 85-90% of cases. According to research, smoking cigars, pipes and marijuana causes the same damage as the cigarettes. All forms of smoking inhibits ciliary movement and the function of the alveolar macrophages. This leads to hyperplasia and hypertrophy of the mucus-secreting glands.

Bronchitis is common worldwide and is one of the top 5 reasons why people seek medical help in many countries. No difference in racial distribution has been reported. Bronchitis most often occurs in autumn or winter. The disorder is seen frequently in countries with a low socioeconomic status and in people who live in urban and industrialized regions. The condition affects more males than females around the world.

The cells of the bronchial-lining tissue of an individual suffering from acute bronchitis are irritated and the mucous membranes become oedematous and hyperaemic [4]. This brings about reduced mucociliary function and clogs up the air passaged with debris thereby increasing irritation. In response, to this a large amount of secretion ensues and this is what brings about the characteristic cough seen with bronchitis.

Chronic bronchitis may equally result due to persistent acute bronchitis attacks or it may arise as a result of heavy smoking or inhalation of air that is contaminated with other pollutants in the environment. When the cough of the smoker is continual instead of occasional, it shows a bronchial lining that has thickened and narrowed the airways to a point where breathing is no longer easy.

There is no way to prevent all cases of acute bronchitis. However, the risk of bronchitis and complications can be reduced by not smoking and by getting flu shots to reduce the risk of getting the flu, which can lead to acute bronchitis [10].

Bronchitis is the inflammation of the mucous membranes found the bronchi. The bronchi is the medium and larger sized airways which carry airflow from the trachea down to the distal parts of the lung [1]. Bronchitis is of two types: acute and chronic.

With acute bronchitis, there is cough and a small sensation at the back of the throat and sputum may or may not be present. This type of bronchitis is seen during the course of an acute viral illness like common cold or influenza.

Chronic bronchitis is characterised by the presence of cough lasting more than 3 months or more every year for at least two consecutive years. It is a type of chronic obstructive pulmonary disease. This type of bronchitis often develops because of a recurrent injury to the airways caused by irritants inhaled by the individual.

Bronchitis occurs when there is inflammation of the lining of your bronchial tubes. The bronchial tubes are responsible for carrying air to and from the lungs. Individuals with bronchitis have cough that produces mucus that is thickened. The mucus may be discolored. Bronchitis can either be acute or chronic. 

Acute bronchitis is the most common type of bronchitis and it often arises as a result of cold or other respiratory infections. On the other hand, chronic bronchitis is the more serious of the two and it arises from regular irritation and inflammation of the lining of the bronchial tubes. The irritation arises from smoking most of the time. 

Acute bronchitis eases off within a few days without any lasting effects but the accompanying cough may last for weeks or more. If repeated cases of  bronchitis happens it is most likely the chronic form that requires medical attention. 

In many cases, bronchitis doesn't lead to any serious physical damages as outlook is very positive. 

1. Knutson D, Braun C. Diagnosis and management of acute bronchitis. Am Fam Physician. May 15 2002;65(10):2039-44. 
2. Black S. Epidemiology of pertussis. Pediatr Infect Dis J. Apr 1997;16(4 Suppl):S85-9.
3. Jivcu C, Gotfried M. Gemifloxacin use in the treatment of acute bacterial exacerbation of chronic bronchitis. Int J Chron Obstruct Pulmon Dis. 2009;4:291-300. 
4. Sethi S, Murphy TF. Infection in the pathogenesis and course of chronic obstructive pulmonary disease. N Engl J Med. Nov 27 2008;359(22):2355-65. 
5. Macfarlane J, Holmes W, Gard P, et al. Prospective study of the incidence, aetiology and outcome of adult lower respiratory tract illness in the community. Thorax. Feb 2001;56(2):109-14. 
6. Gonzales R, Steiner JF, Sande MA. Antibiotic prescribing for adults with colds, upper respiratory tract infections, and bronchitis by ambulatory care physicians. JAMA 1997; 278:901.
7. Gonzales R, Steiner JF, Lum A, Barrett PH Jr. Decreasing antibiotic use in ambulatory practice: impact of a multidimensional intervention on the treatment of uncomplicated acute bronchitis in adults. JAMA 1999; 281:1512.
8. Evertsen J, Baumgardner DJ, Regnery A, Banerjee I. Diagnosis and management of pneumonia and bronchitis in outpatient primary care practices. Prim Care Respir J 2010; 19:237.
9. Kroening-Roche JC, Soroudi A, Castillo EM, Vilke GM. Antibiotic and bronchodilator prescribing for acute bronchitis in the emergency department. J Emerg Med 2012; 43:221.
10. Schuetz P, Amin DN, Greenwald JL. Role of procalcitonin in managing adult patients with respiratory tract infections. Chest 2012; 141:1063.