• 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:
  • cough
  • often purulent sputum
  • dyspnoea
  • wheezing
  • 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

• 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
    • rales
    • 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.

• 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.
  • Long-acting inhaled medicines should not be started in an acute situation, and appropriate investigations should be arranged for the patient later if asthma (Asthma: symptoms and diagnosis) or COPD (Chronic obstructive pulmonary disease (COPD)) is suspected.
• Generally, antimicrobial drugs should not be used for acute bronchitis Dynamed, 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)) Dynamed.
• 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.