Description

• Inflammation of trachea, bronchi, and bronchioles resulting from a respiratory tract infection or chemical irritant (1)
• Cough, the predominant symptom, may last as long as 3 weeks (2,3).
• Generally self-limited, with complete healing and full return of function (2)
• Most infections are viral if no underlying cardiopulmonary disease is present (2).
• Synonym(s): tracheobronchitis

Geriatric Considerations
Can be serious, particularly if part of influenza, with underlying chronic obstructive pulmonary disease (COPD) or congestive heart failure (3)

Pediatric Considerations

• Usually occurs in association with other conditions of upper and lower respiratory tract (trachea usually involved)
• If repeated attacks occur, child should be evaluated for anomalies of the respiratory tract, immune deficiencies, or for asthma.
• Acute bronchitis caused by respiratory syncytial virus (RSV) may be fatal.
• Antitussive medication not indicated in patients age <6 years (2)

Epidemiology

• Predominant age: all ages
• Predominant gender: male = female

• ~5% of adults per year
• Common cause of infection in children

Prevalence
Results in 10 to 12 million office visits per year

Etiology and Pathophysiology

• Viral infections such as adenovirus, influenza A and B, parainfluenza virus, coxsackievirus, RSV, rhinovirus, coronavirus (types 1 to 3), herpes simplex virus, metapneumovirus (2)
• Bacterial infections, such as Chlamydia pneumoniae, Mycoplasma, Bordetella pertussis, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Mycobacterium tuberculosis (2)
• Secondary bacterial infection as part of an acute upper respiratory infection
• Possible fungal infections
• Chemical irritants
• Acute bronchitis causes an injury to the epithelial surfaces, resulting in an increase in mucus production and thickening of the bronchiole wall (1).

Genetics
No known genetic pattern

Risk Factors

• Infants
• Elderly
• Air pollutants
• Smoking
• Secondhand smoke
• Environmental changes
• Chronic bronchopulmonary diseases
• Chronic sinusitis
• Tracheostomy or endobronchial intubation
• Bronchopulmonary allergy
• Hypertrophied tonsils and adenoids in children
• Immunosuppression
  • Immunoglobulin deficiency
  • HIV infection
  • Alcoholism
• Gastroesophageal reflux disease (GERD)

General Prevention

• Avoid smoking and secondhand smoke.
• Control underlying risk factors (i.e., asthma, sinusitis, and reflux).
• Avoid exposure, especially daycare.
• Pneumovax, influenza immunization

Commonly Associated Conditions

• Allergic rhinitis
• Sinusitis
• Pharyngitis
• Epiglottitis (rare but can be rapidly fatal)
• Coryza
• Croup
• Influenza
• Pneumonia
• Asthma
• COPD/emphysema
• GERD