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 10–20 days (1,2).
• 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; Chest cold

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

• Usually occurs in association with other conditions of upper and lower respiratory tract (trachea usually involved) (4).
• If repeated attacks occur, child should be evaluated for anomalies of the respiratory tract, including immune deficiencies, or for chronic asthma.
• When acute bronchitis is caused by respiratory syncytial virus (RSV), it may be fatal.

Epidemiology

• Predominant age: All ages
• Predominant gender: Male = Female

• ~5% of adults per year (3)
• Common cause of infection in children (4)

Prevalence
Results in 10–12 million office visits per year (3)

Risk Factors

• Infants
• Elderly
• Air pollutants
• Smoking
• 2nd-hand smoke
• Environmental changes
• Chronic bronchopulmonary diseases
• Chronic sinusitis
• Tracheostomy
• Bronchopulmonary allergy
• Hypertrophied tonsils and adenoids in children
• Immunosuppression:
  • Immunoglobulin deficiency
  • HIV infection
  • Alcoholism
• Gastroesophageal reflux disease (GERD)

Genetics
No known genetic pattern

General Prevention

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

Pathophysiology

Acute bronchitis causes an injury to the epithelial surfaces, resulting in an increase in mucous production and thickening of the bronchiole wall (1).

Etiology

• Viral infections, such as adenovirus, influenza A and B, parainfluenza virus, coxsackievirus, RSV, rhinovirus, coronavirus (types 1–3), herpes simplex virus (2)
• Bacterial infections, such as Chlamydia pneumoniae (Taiwan acute respiratory [TWAR] agent), Mycoplasma, Bordetella pertussis, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Mycobacterium tuberculosis (2)
• Secondary bacterial infection as part of an acute upper respiratory infection
• Possibly fungal infections
• Chemical irritants

Commonly Associated Conditions

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