Acute bronchitis is inflammation of the medium and large airways, which in most cases is caused by a viral infection. The diagnosis is made based on symptoms, and the cough lasts longer than many people expect. Below are the definitions, timeframes, and boundaries of what is normal.
What acute bronchitis is
Acute bronchitis is a clinical syndrome. It is based on a cough caused by acute self-limiting inflammation of the medium and large airways, the bronchi, without signs of pneumonia.
The inflammation often also affects the trachea. In that case it is called acute tracheobronchitis.
In most people the condition resolves without treatment in about 3 weeks. General symptoms last 7–10 days, and the cough lasts longer.
Chronic bronchitis is a different condition: a productive cough for at least 3 months a year for two years in a row; it is a form of COPD.
Causes of acute bronchitis
Viral infection accounts for more than 90% of cases. Bacteria are found in 1–10% of cases, and their role is debated.
The causative agent can be identified in only 16–30% of cases.
Typical viruses: rhinoviruses, enteroviruses, influenza A and B viruses, parainfluenza viruses, coronaviruses, metapneumovirus, respiratory syncytial virus.
Less often the cause is Mycoplasma pneumoniae or Bordetella pertussis, as well as high levels of air pollution.
Risk factors: tobacco smoke, dust, air pollution. Viruses are transmitted through the air when coughing and through direct contact.
Symptoms of acute bronchitis
The main symptom is a productive cough, that is, one with sputum. The sputum may be purulent.
The average duration of cough is about 17.8 days. Airway hyperresponsiveness persists for up to 5–6 weeks.
- cough with sputum;
- chest pain when coughing;
- shortness of breath and wheezing;
- sore throat, runny nose;
- fever.
Bronchitis is often preceded by an upper respiratory tract infection: headache, nasal congestion, sore throat.
Fever and systemic symptoms are rare in acute bronchitis. If they are present, influenza or pneumonia is suspected.
About 5% of adults and about 6% of children get sick at least once a year. The peak is in autumn and winter.
How acute bronchitis is diagnosed
The diagnosis is usually based on symptoms. Identifying the causative agent in outpatients is usually not required. A chest X-ray helps detect pneumonia.
The color of sputum does not indicate a viral or bacterial infection.
Similar symptoms occur with asthma, pneumonia, bronchiolitis, bronchiectasis, and COPD. Because of this, the diagnosis of acute bronchitis is often made incorrectly.
How bronchitis differs from pneumonia
The difference is built into the definition: acute bronchitis is diagnosed without signs of pneumonia. Pneumonia is a different disease, and a chest X-ray helps detect it.
In acute bronchitis, fever and systemic symptoms are rare. Fever and a severe general condition shift the suspicion toward influenza or pneumonia.
Rapid breathing — more than 30 breaths per minute — is considered a warning sign.
When to see a doctor urgently
Reasons to see a doctor are a cough lasting longer than 3 weeks, blood or streaks of blood in the sputum, chest pain, shortness of breath.
A temperature of 38 °C or higher for longer than 3 days, a very lethargic state, or confusion are also reasons.
A separate group is people with lung and heart diseases: asthma, heart failure.
A separate risk group is people over 65 years of age, pregnant women, people with diabetes, heart, lung, and kidney diseases, and weakened immunity.
Acute bronchitis by itself is not a reason to call an ambulance. Call 103 or 112 if a person is gasping for breath and cannot speak; the lips or skin have become very pale, blue, or gray; confusion has suddenly appeared; a child cannot be woken up or is lethargic.
This material is for reference: it describes symptoms and diagnosis but does not replace a doctor's consultation.
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This content is for reference and does not replace a doctor's consultation. Medical disclaimer