Acute bronchitis

The primary symptom is cough with sputum that may be purulent. The illness may also cause shortness of breath or wheezing. Upper respiratory tract infections (URTI's) often precede acute bronchitis, with overlapping symptoms including headache, nasal congestion, sore throat. Fever and other systemic symptoms are rare in acute bronchitis; their presence raises suspicion for influenza or pneumonia.[14][15]

Acute bronchitis can be caused by contagious pathogens, most commonly viruses. Typical viruses include respiratory syncytial virus, rhinovirus, influenza, and others. Bacteria are uncommon pathogens but may include Mycoplasma pneumoniae, Chlamydophila pneumoniae, Bordetella pertussis, Streptococcus pneumoniae, and Haemophilus influenzae.[16]

• Damage caused by irritation of the airways leads to inflammation and leads to neutrophils infiltrating the lung tissue.
• Mucosal hypersecretion is promoted by a substance released by neutrophils.
• Further obstruction to the airways is caused by more goblet cells in the small airways. This is typical of chronic bronchitis.
• Although infection is not the reason or cause of chronic bronchitis, it is seen to aid in sustaining the bronchitis.

Mild peribronchial cuffing as seen in viral bronchitis

A physical examination will often reveal decreased intensity of breath sounds, wheezing, rhonchi, and prolonged expiration. During examination, physicians rely on history and the presence of persistent or acute onset of cough, followed by a URTI with no traces of pneumonia. Acute bronchitis is typically a clinical diagnosis that relies on patients history and exam, and should be suspected in patients with an acute onset of cough, which often follows a URTI without traces of pneumonia.[17]

Although there is no universally-accepted clinical definition for acute bronchitis, there is a proposed set of practical criteria (Macfarlane, 2001[18]) that include:

• An acute illness of less than three weeks.
• Cough as the predominant symptom.
• At least one other lower respiratory tract symptom, such as sputum production, wheezing, chest pain.
• No alternative explanation for the symptoms.

A variety of tests may be performed in people presenting with cough and shortness of breath:[19]

• A chest X-ray is useful to exclude pneumonia which is more common in those with a fever, fast heart rate, fast respiratory rate, or who are old.[7]
• A sputum sample showing neutrophil granulocytes (inflammatory white blood cells) and culture showing that has pathogenic microorganisms such as Streptococcus species.
• A blood test would indicate inflammation (as indicated by a raised white blood cell count and elevated C-reactive protein).

Decreased breath sounds, crackles, wheezing, and rhonchi that clears with coughs may be heard in the chest. Dullness to percussion and pleural rub suggest disease extension beyond the bronchi such as seen with pneumonia.[14][15] Paroxysms of cough followed by inspiratory whoop and vomiting suggests pertussis.[20]

Prevention is by not smoking and avoiding other lung irritants.[5] Frequent hand washing may also be protective.[5] Furthermore, an oral whole cell nontypeable Haemophilus influenzae vaccine given in the fall has demonstrated short term effectiveness in reducing the frequency and severity of the disease during the winter.[21]

Most cases are self-limited and resolve themselves in a few weeks. Pain medications may help with symptoms.[22] Other recommendations may include rest and keeping well hydrated.[23]

Acute bronchitis usually lasts a few days or weeks.[28] It may accompany or closely follow a cold or the flu, or may occur on its own. Bronchitis usually begins with a dry cough, including waking the patient at night. After a few days, it progresses to a wetter or productive cough, which may be accompanied by fever, fatigue, and headache. The fever, fatigue, and malaise may last only a few days, but the wet cough may last up to several weeks.[29]

Acute bronchitis is one of the most common diseases.[3][13] About 5% of adults are affected and about 6% of children have at least one episode a year.[7][8] It occurs more often in the winter.[7]

In infants under one year of age, acute bronchitis was the most common reason for admission to the hospital after an emergency department visit in the US in 2011.[30]

Wikisource has the text of the 1911 Encyclopædia Britannica article "Bronchitis".

• Acute Bronchitis FamilyDoctor.org (American Academy of Family Physicians)
• "Acute Bronchitis". MedlinePlus. U.S. National Library of Medicine.