OVERVIEW

What is bronchitis?

Bronchitis is a chronic nonspecific inflammation that primarily affects the bronchi, bronchial mucosa, and surrounding tissues^[1]. Its main symptoms include coughing, sputum production, wheezing, shortness of breath, and chest discomfort.

Bronchitis is categorized into acute and chronic types.

• Acute bronchitis is mostly caused by viral infections and typically presents as a cough lasting 2–3 weeks. Treatment focuses on rest, fever reduction, and relieving wheezing. If a bacterial infection is present, antibiotics may be used. With prompt and proper treatment, it is generally curable.

• The primary risk factor for chronic bronchitis is smoking. Clinically, it is characterized by coughing, sputum production, or wheezing lasting at least three months per year for two consecutive years. Treatment includes smoking cessation, oxygen therapy, anti-inflammatory medications, bronchodilators, and expectorants.
  Chronic bronchitis is difficult to cure and can affect a patient's maximum exercise capacity and quality of life. Measures such as pulmonary rehabilitation can help prevent acute exacerbations and reduce their frequency.

Is bronchitis common?

Yes.

Chronic bronchitis is a respiratory disease caused by multiple factors. In China, its prevalence among the elderly is 6.8% (meaning about 68 out of every 1,000 elderly individuals have chronic bronchitis), with a large patient population and severe conditions^[2]. Acute bronchitis is more common in children and is a frequent respiratory infection in pediatrics, though specific epidemiological data are currently lacking^[3].

SYMPTOMS

What are the common symptoms of bronchitis?

• The most common symptom of acute bronchitis is coughing. Other symptoms include phlegm production, wheezing, shortness of breath, and chest tightness. Symptoms typically last about three weeks, though a few patients may experience them for up to six weeks.

• Symptoms of chronic bronchitis include coughing, phlegm production, wheezing, and shortness of breath, especially during exertion. Coughing often worsens in the morning and may be accompanied by yellow or green phlegm or small amounts of blood-streaked sputum.

What are the complications of bronchitis?

Complications of bronchitis include pneumonia, bronchiectasis, emphysema, and chronic obstructive pulmonary disease (COPD).

• Pneumonia: If bronchitis is not treated promptly, it may worsen and affect the alveoli and lung parenchyma, leading to pneumonia. Common symptoms include coughing (with or without phlegm), chest tightness, shortness of breath, and fever.
• Bronchiectasis: Caused by recurrent bronchial infections, it manifests as persistent or recurrent coughing, purulent sputum, and sometimes hemoptysis or difficulty breathing.
• Emphysema: This refers to abnormal, persistent dilation of the distal air spaces and terminal bronchioles, accompanied by destruction of alveolar walls and bronchioles without significant fibrosis. Long-term recurrent bronchial inflammation reduces tissue elasticity, leading to overinflation, increased lung volume, and emphysema. Symptoms include progressively worsening difficulty breathing.
• Chronic Obstructive Pulmonary Disease (COPD): A condition characterized by persistent airflow limitation. Bronchitis can lead to respiratory infections, contributing to COPD. Symptoms include chronic cough, phlegm production, shortness of breath, wheezing, and chest tightness.

CAUSES

What are the causes of bronchitis?

Over 90% of acute bronchitis cases are caused by viral infections (such as influenza virus, respiratory syncytial virus, rhinovirus, etc.). People who smoke, inhale dust, or are exposed to air pollution are more susceptible to infection.

• A small number of acute bronchitis cases are caused by severe air pollution or bacterial infections.
• Most chronic bronchitis cases result from smoking. Additionally, air pollution, irritant gases, and occupational dust exposure (e.g., coal mining, grain handling, textile manufacturing, livestock farming, metal forging) are also risk factors for chronic bronchitis.
• Chronic bronchitis can experience acute exacerbations, often triggered by bacterial infections. Common infectious bacteria include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.
• Immune factors: Abnormal immunity or weakened immune function makes individuals more vulnerable to bacterial and viral infections, increasing the likelihood of bronchitis.
• Seasonal factors: The incidence of chronic bronchitis is higher in winter, with more cases of acute infections occurring during this time.

Who is more likely to develop bronchitis?

• Smokers: Long-term smoking impairs the bronchial ability to clear viruses, making smokers more prone to bronchitis.
• People exposed to irritant gases or harmful dust in their work environment (e.g., coal mining, grain handling, textile manufacturing, livestock farming, metal forging): These irritants can inflame the bronchi, leading to bronchitis.

Is bronchitis contagious?

Acute bronchitis caused by viruses may be contagious. Viruses (such as influenza virus, respiratory syncytial virus, rhinovirus, etc.) can spread through respiratory droplets or direct contact. Mycoplasma infections can also transmit within close-contact settings like households.

DIAGNOSIS

How is bronchitis diagnosed?

If you experience symptoms such as coughing, phlegm production, wheezing, shortness of breath, or chest tightness, seek medical attention promptly. A chest X-ray may be necessary to rule out pneumonia. A doctor will make a definitive diagnosis based on symptoms, clinical presentation, and test results.

What tests are needed for bronchitis?

Tests may include a chest X-ray, complete blood count (CBC), sputum smear or culture, and serological tests.

• A chest X-ray helps detect pneumonia early.
• A CBC helps determine whether the infection is viral or bacterial.
• Sputum smear/culture and serological tests help identify the causative pathogen.
• Chronic bronchitis requires pulmonary function tests to assess airway obstruction and disease progression.

Which diseases are easily confused with bronchitis?

• Lung cancer: Both conditions may cause coughing and chest tightness, but lung cancer patients may also experience bloody sputum, weight loss, and difficulty swallowing. A chest CT can differentiate them.
• Bronchial asthma: Both share symptoms like shortness of breath, chest tightness, and coughing, but asthma may also cause cyanosis (bluish skin). A chest X-ray can help distinguish them.

TREATMENT

Which department should I visit for bronchitis?

Adult patients are advised to visit the respiratory department, while pediatric patients can go to pediatrics, pediatric internal medicine, or pediatric respiratory departments.

Does bronchitis require treatment?

It depends on symptoms, severity, lung function, etc., and should be evaluated by a specialist. Mild cases may resolve on their own.

Treatment is usually symptomatic. If bacterial infection is present, antibiotics may be required.

How is acute bronchitis treated?

Medication:

• Azithromycin: An antibacterial macrolide drug. Suitable for acute bronchitis caused by infection, may cause side effects like indigestion and bloating^[4].
• Carbocisteine: Reduces sputum viscosity, suitable for acute bronchitis with yellow phlegm, may cause nausea, stomach discomfort, or diarrhea^[3].

How is chronic bronchitis treated?

• Medication:
  • Corticosteroids: Control chronic (non-infectious) airway inflammation, helping to relieve swelling and inflammation of the airway epithelium^[5]. Suitable for chronic bronchitis patients.
  • Aminophylline: Reduces airway spasms, alleviating symptoms like wheezing and shortness of breath. May cause nausea, vomiting, agitation, or insomnia^[1].
  • Expectorants (e.g., Bromhexine): Help loosen phlegm and suppress coughs, also effective for acute exacerbations of chronic bronchitis. May cause nausea or stomach discomfort^[1].
  • Antibiotics (e.g., Penicillin, Cefalexin): Control bacterial infections, may cause nausea, vomiting, diarrhea, or rashes^[1].
• Nebulization: Common drugs include budesonide and salbutamol. Helps dilute secretions for easier expectoration. May cause hoarseness, throat irritation, or coughing^[5].
• Oxygen therapy: Recommended for patients with oxygen saturation below 90%. Long-term low-flow oxygen can relieve hypoxemia and improve survival rates.

How is pediatric bronchitis treated?

• Ambroxol Hydrochloride: A mucolytic agent that thins mucus. Suitable for children, may cause allergic reactions (e.g., swelling, rash, itching)^[6].
• Ribavirin: Inhibits respiratory syncytial virus in pediatric bronchitis. May cause nausea, vomiting, or loss of appetite^[6].

Can bronchitis be completely cured?

Acute bronchitis can be cured^[3]; chronic bronchitis is usually incurable but treatment can slow lung function decline^[1].

DIET & LIFESTYLE

What should bronchitis patients pay attention to in their diet?

• Consume adequate fluids in small, frequent amounts. This not only helps thin mucus and facilitates expectoration but also promotes blood circulation, accelerates metabolism, and aids in reducing body temperature while maintaining fluid balance.
• Eat more protein-rich foods such as lean meat, eggs, fish, shrimp, and milk to boost immunity.
• Increase intake of fresh vegetables and fruits like leafy greens, tomatoes, kiwis, lemons, and apples to replenish vitamins and strengthen physical health.

What should bronchitis patients pay attention to in daily life?

• Maintain a balanced diet and engage in moderate exercise to enhance physical fitness. Ensure sufficient sleep daily.
• Practice self-regulation when experiencing high stress or emotional tension.
• Adjust clothing according to weather changes to avoid catching cold.
• Keep living environments clean and hygienic, disinfect regularly to prevent bacterial infections, and ventilate frequently to avoid inhaling irritants or dust.
• Reduce outdoor activities during flu season, wear masks when going out, and minimize exposure to viruses.
• Schedule rest and activity appropriately to avoid overexertion.

PREVENTION

How to prevent bronchitis?

• Prevention of acute bronchitis includes frequent handwashing, quitting smoking (avoiding secondhand smoke), and avoiding environmental pollution.
• The most important prevention for chronic bronchitis is quitting smoking. Additionally, avoiding colds and respiratory irritants helps reduce acute flare-ups of chronic bronchitis.
• Get vaccinated against influenza and pneumonia to prevent illness.