Chronic bronchitis Chronic bronchitis, abbreviated as chronic bronchitis, is a chronic non-specific inflammation of the tracheal and bronchial mucosa and its surrounding tissues caused by infectious or non-infectious factors. The occurrence of this disease is related to chronic irritation, such as long-term exposure to smoking, harmful dust, smoke (biomass fuel), and air pollution. In addition, viruses, bacteria, allergens, climate change, etc., can also lead to the onset of the disease.

Closely related to long-term stimulation by infectious or non-infectious factors

Clinical manifestations include cough, sputum production, or wheezing

Occurs annually for 3 months, for 2 years or more

Main treatments include anti-infection, bronchodilation, and expectorant therapy

Chronic bronchitis, commonly referred to as "chronic bronchitis" or "chronic bronchial inflammation," refers to chronic non-specific inflammation of the trachea, bronchial mucosa, and surrounding tissues caused by infectious or non-infectious factors.

The occurrence of this disease is associated with chronic stimulation, such as long-term exposure to smoking, harmful dust, smoke (biomass fuel), and atmospheric pollution. Additionally, viruses, bacteria, allergens, and climate changes can also contribute to the onset of the disease.

Chronic bronchitis is a common and prevalent disease, affecting 3.4% to 22.0% of adults. Individuals over 45 years of age, smokers, those living or working in areas with severe air pollution, and patients with chronic obstructive pulmonary disease (COPD) are all at higher risk of developing chronic bronchitis.

The exact causes of chronic bronchitis are not fully understood, but common factors include the following:

Infection

Viral, mycoplasma, and bacterial infections are significant contributors to the development and progression of chronic bronchitis. Common viral pathogens include influenza viruses, rhinoviruses, adenoviruses, and respiratory syncytial viruses.

Bacterial infections often occur as a secondary infection following a viral infection, with common pathogens including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus. These infectious agents lead to damage to the tracheobronchial mucosa and chronic inflammation.

Other factors

The patient's compromised immune function, airway hyperresponsiveness, and age are all related to the onset and development of chronic bronchitis.

Smoking

Smoking is a major predisposing factor for chronic bronchitis. Smokers have a 2-8 times higher incidence of chronic bronchitis compared to non-smokers. Chemical substances in tobacco, such as tar, nicotine, and hydrogen cyanide, can damage the airway mucosa.

Occupational dust and chemicals

Exposure to occupational dust and chemicals, including smoke, allergens, industrial emissions, indoor air pollution, or biomass fuel, can promote the onset of chronic bronchitis when the exposure concentration and duration are high.

Atmospheric pollution

Harmful gases in the atmosphere, such as sulfur dioxide, nitrogen dioxide, and chlorine, can damage the epithelial cells of the airway mucosa, increasing the susceptibility to bacteria and other pathogens.

Cough

Patients with chronic bronchitis typically experience morning coughing, and may also cough during sleep.

Sputum production

The sputum produced by patients is generally white and frothy or mucoid, occasionally tinged with blood. Sputum production is typically higher in the morning, and patient movement or changes in position can stimulate sputum production.

Wheezing, shortness of breath

Significant wheezing may indicate concurrent bronchial asthma. If accompanied by emphysema, it may manifest as shortness of breath after exertion, indicating progression to the stage of chronic obstructive pulmonary disease (COPD).

X-ray examination

In the early stages, X-ray examinations of chronic bronchitis may show no abnormalities. However, in cases of recurrent attacks, X-ray images may reveal thickened, disordered lung markings, presenting as linear, reticular, or patchy shadows, with more prominent changes in the lower lung fields.

Blood tests

In cases of bacterial infection, blood routine tests may show an increase in total white blood cell count and/or neutrophil percentage.

Sputum examination

Pathogenic bacteria can be cultured from patient sputum. Sputum smear examinations commonly reveal gram-positive or gram-negative bacteria, as well as damaged white blood cells and goblet cells.

Pulmonary function tests

In the early stages, pulmonary function may show no abnormalities. However, the determination of maximum expiratory flow-volume curves may reveal a significant decrease in expiratory flow at 50% and 75% of lung capacity in patients with small airway obstruction.

If the patient's forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) ratio (FEV1/FVC) is less than 0.70 after using bronchodilators, it indicates that chronic bronchitis has progressed to chronic obstructive pulmonary disease (COPD).

Pulmonary tuberculosis

Patients with pulmonary tuberculosis often experience symptoms such as fever, night sweats, fatigue, and weight loss. Acid-fast bacilli can be found in the patient's sputum, and nucleic acid testing and chest X-rays can aid in differentiation.

Eosinophilic bronchitis

This condition presents with clinical symptoms similar to chronic bronchitis, and X-ray examinations may show no abnormalities or only increased lung markings. Bronchial provocation tests are often negative, leading to frequent misdiagnosis. Differential diagnosis requires induced sputum examination, with eosinophilic bronchitis patients having an eosinophil cell proportion of ≥3% in the induced sputum.

Idiopathic pulmonary fibrosis

This disease progresses slowly, with initial symptoms of cough and sputum production, occasional dyspnea, crackles in the lower lungs upon auscultation, decreased arterial oxygen pressure in blood gas analysis, and normal blood carbon dioxide pressure. High-resolution spiral CT examinations aid in diagnosis.

Bronchogenic carcinoma

Patients with bronchogenic carcinoma often have a history of smoking, experience recurrent irritative coughing, or have a history of coughing, with recent changes in the nature of the cough. Some patients may exhibit blood in their sputum. Additionally, some patients experience recurrent obstructive pneumonia, with pneumonia that does not resolve after antibiotic treatment. Cytological examination of sputum, chest CT, and fiberoptic bronchoscopy aid in definitive diagnosis.

Bronchiectasis

Patients typically produce copious amounts of purulent sputum, and some may experience hemoptysis. X-rays commonly show coarse and curly lung markings, and high-resolution spiral CT examinations aid in differential diagnosis.

Bronchial asthma

For some patients, irritative cough is the primary characteristic, triggered by irritants such as cooking fumes, dust, or cold air. However, patients with bronchial asthma often have a family history of the disease, and some have a history of allergies. Positive bronchial dilation tests or bronchial provocation tests can aid in differentiation.

Other diseases causing chronic cough

Differential diagnosis is required to distinguish chronic bronchitis from upper respiratory cough syndrome, gastroesophageal reflux, cough hypersensitivity syndrome, or certain cardiovascular diseases (such as mitral stenosis).

Patients should actively quit smoking.

Avoid exposure to and inhalation of harmful gases or smoke in daily life.

Engage in regular physical exercise and avoid catching colds.

For patients with recurrent respiratory infections, influenza and pneumococcal vaccines can be administered for prevention.

Due to significant individual differences, there is no absolute "best," "fastest," or "most effective" medication. In addition to common over-the-counter drugs, the most appropriate medication should be selected based on individual circumstances under the guidance of a physician.

Infection control

During acute exacerbations of chronic bronchitis, physicians may administer anti-infective therapy. Antibiotics are selected based on the common pathogens in the patient's location, such as levofloxacin, amoxicillin, etc. Oral administration is typical, and in severe cases, short-term intravenous administration may be necessary. If pathogenic bacteria are cultured, antibiotics can be selected based on sensitivity testing.

Antitussive and expectorant drugs

For patients with dry cough, antitussive drugs such as compound licorice preparations, compound methoxyphenamine, or dextromethorphan can be used. Expectorants include acetylcysteine, bromhexine, ambroxol hydrochloride, and primrose oil, among others.

Bronchodilators

Patients with significant wheezing may require exclusion of bronchial asthma and may benefit from bronchodilator therapy, such as theophylline, β2-adrenergic receptor agonists, or anticholinergic drugs for inhalation therapy.

Patients should quit smoking and avoid exposure to secondhand smoke.

Avoid exposure to smoke or occupational dust.

Avoid exposure to indoor and outdoor polluted air.

Avoid cold and catching colds.

Quitting smoking and avoiding exposure to secondhand smoke, as well as avoiding exposure to air-borne irritants to the bronchi, are recommended.

Frequent ventilation to avoid colds and catching colds.

Vaccination with influenza and pneumococcal vaccines is recommended.