Download Acute inflammation of the tracheobronchial tree in patients with

Acute bronchitis is inflammation of the tracheobronchial tree, commonly following
a URI, that occurs in patients without chronic lung disorders. The cause is almost
always a viral infection. The pathogen is rarely identified. The most common
symptom is cough, with or without fever, and possibly sputum production.
Diagnosis is based on clinical findings. Treatment is supportive; antibiotics are
usually unnecessary. Prognosis is excellent.
Acute bronchitis is frequently a component of a URI caused by rhinovirus,
parainfluenza, influenza A or B virus, respiratory syncytial virus, coronavirus, or
human metapneumovirus. Less common causes may be Mycoplasma
pneumoniae, Bordetella pertussis, and Chlamydia pneumoniae. Less than 5% of
cases are caused by bacteria, sometimes in outbreaks.
Acute inflammation of the tracheobronchial tree in patients with underlying
chronic bronchial disorders (eg, COPD, bronchiectasis, cystic fibrosis) is
considered an acute exacerbation of that disorder rather than acute bronchitis. In
these patients, the etiology, treatment, and outcome differ from those of acute
bronchitis (see also Chronic Obstructive Pulmonary Disease (COPD) : Treatment
of Acute COPD Exacerbation).
PEARLS & PITFALLS

Acute cough in patients with COPD, bronchiectasis, or cystic fibrosis
should typically be considered an exacerbation of that disorder rather
than simple acute bronchitis.
Symptoms and Signs
Symptoms are a nonproductive or mildly productive cough accompanied or
preceded by URI symptoms, usually by > 5 days. Subjective dyspnea
results from chest pain or tightness with breathing, not from hypoxia. Signs
are often absent but may include scattered rhonchi and wheezing. Sputum
may be clear, purulent, or occasionally contain blood. Sputum
characteristics do not correspond with a particular etiology (ie, viral vs
bacterial). Mild fever may be present, but high or prolonged fever is
unusual and suggests influenza or pneumonia.
On resolution, cough is the last symptom to subside and often takes 2 to 3
wk or even longer to do so.
Diagnosis
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Clinical evaluation
Sometimes chest x-ray to exclude other disorders
Diagnosis is based on clinical presentation. Testing is usually unnecessary.
However, patients who complain of dyspnea should have pulse oximetry to
rule out hypoxemia. Chest x-ray is done if findings suggest serious illness
or pneumonia (eg, ill appearance, mental status change, high fever,
tachypnea, hypoxemia, crackles, signs of consolidation or pleural effusion).
Elderly patients are the occasional exception, as they may have pneumonia
without fever and auscultatory findings, presenting instead with altered
mental status and tachypnea.
Sputum Gram stain and culture usually have no role. Nasopharyngeal
samples can be tested for influenza and pertussis if these disorders are
clinically suspected (eg, for pertussis, persistent and paroxysmal cough
after 10 to 14 days of illness, only sometimes with the characteristic whoop
and/or retching, exposure to a confirmed case—see also Pertussis :
Diagnosis).
Cough resolves within 2 wk in 75% of patients. Patients with persistent
cough should undergo a chest x-ray. Evaluation for noninfectious causes,
including postnasal drip and gastroesophageal reflux disease, can usually
be done clinically. Differentiation of cough-variant asthma may require
pulmonary function testing.
Treatment


Symptom relief (eg, acetaminophen, hydration, possibly antitussives)
Inhaled β-agonist or anticholinergic for wheezing
Acute bronchitis in otherwise healthy patients is a major reason that
antibiotics are overused. Nearly all patients require only symptomatic
treatment, such as acetaminophen and hydration. Evidence supporting
efficacy of routine use of other symptomatic treatments, such as
antitussives, mucolytics, and bronchodilators, is weak. Antitussives should
be considered only if the cough is interfering with sleep (see Treatment).
Patients with wheezing may benefit from an inhaled β 2 -agonist
(eg, albuterol) or an anticholinergic (eg, ipratropium) for a few days. Oral
antibiotics are typically not used except in patients with pertussis or during
known outbreaks of bacterial infection. A macrolide such
as azithromycin 500 mg po once, then 250 mg po once/day for 4 days
or clarithromycin 500 mg po bid for 14 days is given.
PEARLS & PITFALLS

Treat most cases of acute bronchitis in healthy patients without using
antibiotics.
Key Points

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Acute bronchitis is viral in > 95% of cases, often part of a URI.
Diagnose acute bronchitis mainly by clinical evaluation; do chest xray and/or other tests only in patients who have manifestations of
more serious illness.
Treat most patients only to relieve symptoms.