- The essential symptoms of acute bronchitis are cough and expectoration of sputum that have lasted less than 3 weeks. In addition, there are usually other symptoms of respiratory tract infection (rhinitis, sore throat, hoarseness).
- Acute bronchitis is usually a viral infection that does not require antimicrobial therapy.
- The most important issue in the diagnostics is to exclude pneumonia.
- The causative pathogens vary according to the epidemiological situation. The most common causative agents include coronaviruses, rhinoviruses, respiratory syncytial (RS) viruses, adenoviruses, parainfluenza and influenza viruses.
- An aetiological diagnosis cannot be made based on symptoms and clinical findings.
- Symptoms of acute bronchitis include:
- often purulent sputum
- thoracic pain
- fever rather rarely (10–30% of patients present with fever).
- The duration of cough is about 2 weeks in most patients.
- Acute bronchitis is usually associated with an infection in the upper respiratory tract and therefore the patient simultaneously has rhinitis, sore throat and hoarseness.
- General symptoms are common: headache and debilitation occur in half of patients, muscle pain in one in four.
- Diagnosis is based on patient history, clinical examination and follow-up of the further course.
- Microbiological tests are of no benefit, except when influenza is suspected in cases where its drug treatment would be indicated.
- It is essential to identify the patients in whom pneumonia should be suspected (see Differential diagnosis).
- In a generally healthy person without significant general symptoms (heart rate < 100/min, respiratory rate < 20/min, body temperature < 38°C) and without pneumonic rales on auscultation or dullness to percussion, the probability of pneumonia is very small.
- The most important differential diagnosis to consider is pneumonia (Pneumonia). It is significantly less common than bronchitis.
- The differential diagnosis cannot be based on clinical symptoms and laboratory findings alone. Bronchitis and pneumonia are often caused by the same microbes – these diagnoses constitute differences in severity of the same disease.
- In bronchitis the infection is limited to the mucous membranes of the bronchial tree while pneumonia represents an inflammation of the lung parenchyma, and its symptoms are therefore more severe.
- Pneumonia may be suspected if the patient has the following symptoms:
- increased respiratory rate > 20/min
- tachycardia (> 100/min)
- abnormal findings in the respiratory exam
- decreased breath sounds
- dullness to percussion
- vocal resonance over a larger area than normal
- oxygen saturation < 92% in room air.
- If pneumonia is suspected, plain x-ray of the chest should be performed.
- Taking a chest x-ray is further recommended in patients
- with impaired general condition
- with a prolonged or unusual course of the disease
- with a primary disease, e.g. COPD, bronchiectasis, diabetes, or chronic cardiac, hepatic or renal disease predisposing them to pneumonia
- with a history of pneumonia within the past year.
- CRP > 100 mg/l strongly suggests pneumonia. If the CRP is < 20 mg/l and there are no symptoms or signs fitting pneumonia, pneumonia is unlikely.
- In patients with severe symptoms, low CRP concentration does not exclude the possibility of a serious bacterial disease. CRP measurement is not reliable in the differential diagnostics if the symptoms have lasted less than 24 h.
Other differential diagnoses
- The possibility of sinusitis (Acute maxillary sinusitis) should be excluded by ultrasound examination or x-ray in patients with persisting symptoms or local signs of sinusitis. Cough is a common symptom also in common cold, asthma and COPD.
- The following conditions that sometimes resemble bronchitis should be borne in mind:
- farmer's lung (Allergic alveolitis)
- pulmonary toxicity of nitrofurantoin.
Treatment and management
- Supportive care
- Symptomatic treatment
- Symptomatic treatment may help the patients cope with their symptoms. There is no clear evidence for the effectiveness of cough medicines [Evidence Level: D].
- Honey, eucalyptus oil or any liquid that moistens the pharynx or larynx may alleviate cough, particularly when it is associated with an upper respiratory infection.
- Of symptoms of upper respiratory tract infection, nasal congestion and mucus production can be alleviated by anticholinergics and sympathomimetics.
- The benefit from sympathomimetics in the treatment of bronchitis is debatable [Evidence Level: C]. Patients with obstruction associated with acute respiratory tract infection may benefit from sympathomimetics.
- Generally, antimicrobial drugs should not be used for acute bronchitis, because it is usually a viral infection.
- Antimicrobial treatment may be considered if the patient's condition is regarded as an exacerbation of COPD (Chronic obstructive pulmonary disease (COPD)).
- Because the course of the disease cannot be predicted from the clinical picture or the laboratory findings, regardless of whether or not antimicrobial therapy is performed, a patient with acute bronchitis must be given a new appointment if symptoms persist or become worse.
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