What are the diagnostic criteria for bronchitis (inflammation of the bronchial tubes)?

From the Guidelines

Bronchitis is diagnosed through a combination of clinical evaluation, patient history, and sometimes diagnostic tests, with a focus on excluding other conditions such as pneumonia, the common cold, acute asthma, or an exacerbation of COPD, as recommended by the most recent guidelines 1. The diagnosis of bronchitis relies heavily on the pattern of symptoms, particularly a persistent cough with mucus production, along with physical examination findings and, when needed, supporting diagnostic tests.

Key Diagnostic Criteria

• Clinical evaluation and patient history
• Exclusion of other conditions such as pneumonia, the common cold, acute asthma, or an exacerbation of COPD
• Physical examination findings, including abnormal breathing sounds like wheezing or crackling
• Diagnostic tests, such as chest X-rays, pulmonary function tests, blood tests, and sputum cultures, may be ordered to support the diagnosis

Important Considerations

• Acute bronchitis is considered a self-limiting condition, and antibiotics are usually unnecessary unless there's evidence of a bacterial infection 1
• The 2020 guidelines suggest that routine ordering of investigations such as chest x-rays, sputum cultures, measurement of serum inflammatory markers, or other laboratory tests at initial presentation may not be necessary 1
• A detailed review and exploration of preexisting health conditions, exposure history, and consideration of differential diagnoses are crucial in diagnosing acute bronchitis 1

Diagnostic Approach

• The diagnosis of acute bronchitis should be made only when there is no clinical or radiographic evidence of pneumonia, and the common cold, acute asthma, or an exacerbation of COPD have been ruled out as the cause of cough 1
• A chest X-ray may be ordered to rule out pneumonia, while pulmonary function tests might be used for chronic bronchitis diagnosis, as recommended by the guidelines 1

From the Research

Diagnostic Criteria for Bronchitis

The diagnostic criteria for bronchitis are primarily based on clinical presentation, as stated in the studies 2, 3, 4, 5, 6.

• The most common symptom of bronchitis is cough, which can be productive or non-productive, and typically lasts for about two to three weeks 4, 5.
• Other symptoms may include purulent sputum, abnormal lung examinations, and a sore throat 3.
• The presence or absence of colored sputum does not reliably differentiate between bacterial and viral lower respiratory tract infections 4.
• Viruses are responsible for more than 90 percent of acute bronchitis infections, and antibiotics are generally not indicated for bronchitis 4, 5.

Differential Diagnosis

It is essential to differentiate acute bronchitis from other common diagnoses, such as:

• Pneumonia: characterized by tachypnea, tachycardia, dyspnea, or lung findings suggestive of pneumonia, and radiography is warranted 5.
• Asthma: may require specific therapies not indicated for bronchitis 4.
• Pertussis: should be suspected in patients with cough persisting for more than two weeks, accompanied by symptoms such as paroxysmal cough, whooping cough, and post-tussive emesis, or recent pertussis exposure 5.

Diagnostic Evaluation

The diagnostic evaluation of bronchitis includes:

• Clinical assessment: history and physical examination to rule out secondary causes for cough, such as pneumonia 5.
• Laboratory tests: not frequently used in making the diagnosis of acute bronchitis, but may be necessary to rule out other conditions 3, 5.
• Radiography: warranted if pneumonia is suspected 5.