- 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.
- Acute bronchitis is usually caused by a virus.
- 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 of 38.0 °C or more (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.
- 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, a CRP assay is performed; if the plasma CRP is 30 mg/l or more or the patient has symptoms or findings suggestive of pneumonia, radiological confirmation by chest X-ray is recommended.
- A low CRP concentration in association with absence of findings suggestive of pneumonia rules out pneumonia with a high level of certainty.
- A low CRP concentration does not exclude the possibility of a serious bacterial disease in patients with severe symptoms. CRP measurement is not reliable in the differential diagnostics if the symptoms have lasted less than 24 h.
- 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.
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.
- Antimicrobial drugs should not be used for acute bronchitis in patients who are otherwise healthy and in good general condition, because the infection is usually viral. Antimicrobial treatment should be reserved for patients who benefit from it, e.g. those at great risk of pneumonia.
- Antimicrobial treatment should be considered more readily if
- the patient is over 75 years old and has high fever
- the patient suffers from a severe general disease, cardiac insufficiency, COPD, insulin-treated diabetes or severe neurological disease or is on immunosuppressive medication, or
- the patient is an alcoholic.
- If antimicrobial treatment is considered indicated, 750 mg amoxicillin three times daily without clavulanic acid or, in the case of penicillin allergy, 150 mg doxycycline once daily is prescribed. The duration of treatment is 5 to 7 days.
- Doxycycline is the drug of choice if mycoplasma or chlamydia is suspected.
- No broad-spectrum antimicrobials should be used in the treatment of acute bronchitis without special grounds.
- Delayed prescribing decreases the number of antimicrobial drug courses [Evidence Level: A] and revisits. If the physician considers that the patient may be in need of antimicrobial therapy, a prescription is given to the patient with instructions to start the medication if the symptoms have not subsided within 2 weeks.
- Antimicrobial treatment should be considered more readily if
- 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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