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Chronic Bronchitis


Chronic bronchitis is a type of chronic obstructive pulmonary disease, along with emphysema and small airway disease, and is one of the most interesting respiratory diseases in recent years. The number of patients is increasing rapidly due to the pollution, the smoking population and the elderly population.

Chronic obstructive pulmonary disease is a disease in which the airway narrows gradually and air flow is restricted (irreversible airway obstruction). As the disease progresses, clinical symptoms and laboratory findings of the two or three diseases are mixed, and it is difficult to differentiate them. Treatments are also similar and collectively called chronic obstructive pulmonary disease.

Airway obstruction usually progresses gradually, causing abnormal inflammatory reactions to the lungs by harmful particles or gases.

Chronic bronchitis may not have airflow obstruction, in which case it is not classified as a category of chronic obstructive pulmonary disease.

Assuming that there is no clinically different condition, chronic bronchitis can be diagnosed if the patient has cough and sputum at least three months a year for two consecutive years. Chronic bronchitis can be divided into three categories as follows.

1. Simple Chronic Bronchitis

Prolonged exposure to bronchial irritants, such as smoking, increases the secretion of mucus in the patient’s airways, and clinically, sputum-related cough appears for more than three months a year for two consecutive years. If there is no specific disease that can cause respiratory symptoms, such as bronchiectasis or pulmonary tuberculosis, chest X-rays can be diagnosed as simple chronic bronchitis.

Patients with simple chronic bronchitis often have colony formations in the airways, and airway infections frequently occur, and when the disease progresses due to repeated airway infections, it is common to transition to chronic obstructive bronchitis.

2. Chronic Obstructive Bronchitis

Chronic bronchitis develops and airway obstruction is accompanied by symptoms of airway obstruction in addition to the symptoms of sputum and cough. In severe cases, it can be accompanied by hypoxia and hypercarbemia. Pulmonary function tests also show obstructive ventilation.

In the early stages of chronic obstructive bronchitis, airway obstruction is often improved by bronchodilators. However, if the disease continues to progress, there are a number of irreversible factors that eventually make it difficult to breathe (breath failure), accompanied by a condition in the heart (pulmonary heart).

3. Asthmatic Bronchitis

Asthma attacks are a common condition in chronic obstructive airway disease. In strict sense, asthma is a reversible airway obstruction.

However, chronic obstructive bronchitis, an irreversible airway obstruction, is often difficult to distinguish from asthma attacks when severe airway obstruction with strong reversible factors develops. When an asthma attack (a sudden symptom of bronchial asthma) subsides, it is a group of disorders with a large number of reversible elements that show only symptoms of chronic bronchitis.

Chronic bronchitis is a relatively common disease. The prevalence of chronic bronchitis is affected by the tobacco habits of the society. One-third of smokers aged 35 to 60 years have chronic bronchitis.

In addition to industrialization and aging, the probability of chronic bronchitis has increased. As a result, the mortality rate and economic and social burdens are significant.

Previously, it was more common in males and urban residents after 40 years of age, but the incidence of chronic bronchitis in women has also increased as women’s smoking rate increases.


Functional and structural changes

Airway obstruction is caused by changes in the airway lumen, airway wall, or airway surroundings. This can be caused by increased secretion (changes in the airways) or inflammation of the airways and swelling (changes in the airway walls) or destruction of the lung parenchyma (changes around the airways). There are many hypotheses about the mechanisms that cause airway obstruction, but the proteolytic enzyme imbalance and reactive oxygen species are known as the main causes.
Inflammatory cells are stimulated by various stimuli such as tobacco smoke and protease production increases. At the same time, reactive oxygen species are produced, destroying lung tissue and causing inflammatory reactions, causing small airway disease. If irritation or inflammation continues in this condition, chronic bronchitis develops.

Infections and inhalation of irritants increase the secretion of mucus in the airways and decrease the function of the cilia, resulting in a loss of mucus output. In addition, phagocytic dysfunction in the lungs reduces resistance to infection, causing airway infections to repeat.


There are many causes of chronic bronchitis, but smoking, recurring airway infections, air pollution, genetic factors and occupational factors exposed to dust and irritant gases are relatively important. These causes cause chronic inflammation in the airways and increase the number and size of mucous glands and mucus secreting cells in the airway mucosa.

1. Tobacco

Smoking is the most important cause of chronic obstructive pulmonary disease. Respiratory symptoms and pulmonary dysfunction are more often seen in smokers than nonsmokers. This difference is directly proportional to the amount of smoking. Most patients have a smoking history. Patients with chronic obstructive pulmonary disease have a smoking history of at least 20 pack years (1 pack year: if they smoke 1 year per day), and most patients have a pack of 40 pack years.

2. Respiratory Infections

Childhood respiratory infections are associated with decreased lung function and increased respiratory symptoms after adulthood, but it is still controversial to consider this as a risk factor for developing chronic bronchitis.

3. Occupational Exposure

If there is strong and constant exposure, occupational dust (eg coal dust) and chemicals (steam, irritants, smoke) can also be the cause.

4. Air Pollution

While it is still unclear what specific elements of air pollution are harmful, there is evidence that dust in air pollution will add to the total inhalation accumulation of the lungs.

In addition, indoor air pollution caused by the combustion of organic energy used for cooking or heating in non-ventilated residential areas can also be a cause.

5. Sex

In the past, men were more likely to have chronic obstructive pulmonary disease because of the higher rate of smoking and occupational exposure than women, but nowadays, the proportion of women is increasing due to the increase in women’s smoking rate and social advancement.

6. Other Possible Factors

Other than that, it is not clear, but it is also associated with atopy, childhood respiratory infections, bronchial hyperresponsiveness, dry physique, low socioeconomic environment, alcohol, diet and nutrition (lack of vitamin C diet), decreased immunity, hormones, family history, genetic predisposition, climate, etc. There is a possibility.


Chronic bronchitis can be diagnosed by clinical findings. In the early stages of the disease, there may be no symptoms. Chronic bronchitis is a major symptom of cough and sputum, initially severe in winter, but can continue throughout the year as the disease progresses.

The initial symptoms are a chronic cough, which sometimes occurs intermittently, but sometimes it is constantly changing day after day, and even worse, the cough continues during sleep.

Sputum is sticky, low in volume and discharged with a cough in the morning. However, sputum can progress and worsen over time.

Respiratory infections can return frequently and dyspnea is an important symptom of visiting a hospital, disrupting daily life and progressing once it occurs.

Shortness of breath does not appear well unless the lung function drops to a certain level. The difficulty of breathing can be thought that the course of the disease is quite old. However, even in the early stages, you may have difficulty breathing compared to your lung function.

Some patients who have already been diagnosed with chronic bronchitis may suddenly worsen their symptoms, such as coughing, sputum and dyspnea more often. Sputum usually comes out as mucus, dark yellow or light green, and sometimes blood comes out. This deterioration usually occurs in winter, when the upper respiratory tract infection is high, and the more severe the chronic bronchitis, the faster it worsens.

The cause of exacerbation is mainly due to bacterial infection of the bronchus and is the most common cause of chronic bronchitis patients being hospitalized. It is an important cause of death.

As the disease progresses, severe weight loss and muscular loss may occur.

1. Clinical Findings

The physical findings of people with mild or moderate chronic bronchitis are usually normal.

The respiratory rate is normal or slightly increased, and in severe cases, the respiratory rate is increased (usually more than 20 times per minute) and hypoxia or hypercarbon dioxide may be present.

The shape of the rib cage can also change, and a โ€œbarreled rib cageโ€ can be observed, which bulges before and after the rib cage.

There may be an overweight initially, and gradually progress in weight loss.

Breathing sounds are reduced in the auscultation and heart sounds are hard to hear. Occasionally, you may hear bubbles or wheezing (wheezing when you exhale).

If hypoxia is severe, cyanosis is seen, with a blue lip on the lips or under the nails. The exhalation of the lips is prolonged and exhaled.

If the course of the disease is very advanced, the inhalation between the ribs can be reduced when you inhale, and the use of secondary respiratory tracts around the neck is observed. Increasing pulmonary artery pressure can overwhelm the heart, which can be accompanied by systemic edema, especially lower extremity or facial edema.

The diagnosis can be made with an accurate medical history and a physical examination, but the examination can determine the severity and can help with treatment.

2. Tests

1) Lung function test / Lung capacity test after bronchodilator

In the case of simple chronic bronchitis, normal lung function tests usually show normal findings.

In patients with obstructive bronchitis, airway obstruction is observed. If there are symptoms such as smoking, coughing, or sputum, even if there is difficulty breathing, there is a screening test. Pulmonary function tests are important because they are used as objective indicators in assessing the effectiveness of treatment and predicting prognosis during diagnosis, during and after treatment.

The test items used were forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and ratio of forced expiratory volume (FEV1 / FVC) for 1 second.

Occasionally, severe symptoms of acute chronic bronchitis show a mild decrease in FEV1. Further progression of the disease at this stage results in irreversible reduction of FEV1 in pulmonary function tests.

Sometimes inhalation of bronchodilators is followed by changes in FEV1 before and after inhalation, which is done to look for reversibility of the bronchus.

2) Chest X-ray

Chest X-rays do not directly help diagnose, but they are useful for differentiating from other diseases, and as the disease progresses, an increase in bronchial-vascular shading is seen.

In chronic bronchitis, chest imaging is usually normal, even with typical clinical symptoms. However, an increase in pulmonary shading in chest images often results in a ‘dirty lung’, or thickening of the bronchial wall and the appearance of railroad tracks can be helpful in diagnosing chronic bronchitis.

3) Sputum test

4) blood test

5) ECG test

6) Other helpful tests

  • Pulmonary Diffusion Test
  • Allergic skin test
  • Blood IgE Test
  • Chest computed tomography (not necessary for diagnosis and useful for differentiating other diseases)
  • Arterial blood gas test (not required for mild but moderate to severe levels, especially in patients with pulmonary vascular hypertension and pulmonary heart)


It is better to look at the treatment of chronic obstructive pulmonary disease without explaining chronic bronchitis separately. Treatment of chronic bronchitis in a steady state provides step-by-step treatment depending on the severity of the disease. It minimizes the side effects of treatment, includes a number of goals, and is based on an individual assessment of the extent of the disease and the response to treatment. The purpose of treatment for chronic bronchitis is to:

  • Airway extension
  • Symptom control
  • Treatment and prevention of airway infections
  • Improve athletic ability
  • Appropriate Treatment of Complications
  • Treatment and prevention in case of exacerbation
  • Stop using sedatives with quitting smoking
  • Treatment of mental illness

Treatment is largely divided into drug treatment and non-drug treatment.

1. Medications

1) Bronchodilator treatment

Generally, the effect of bronchodilator is not obvious in the case of simple chronic bronchus. However, in the case of chronic obstructive bronchitis, bronchodilator may improve the patient’s symptoms. Commonly used bronchodilators are:

(1) sympathetic receptor agonists

Beta 2 sympathomimetics are representative bronchodilators that selectively act on the bronchi. Drugs with selective hyperactivity in the bronchus may reduce unwanted side effects from other sympathetic effects.

(2) theophylline preparations

These drugs have been widely used in the past for the treatment of obstructive airway disease. Recently, the sustained-release drugs have been developed and used to maintain blood levels, simplify the administration method, and reduce side effects.

When using theophylline drugs, keep in mind that depending on the patient’s disease or other drugs being administered, the blood removal rate of theophylline drugs may vary. Increasing blood levels may increase the risk of drug toxicity. In addition, even if the same amount is administered by reducing the blood concentration severely, bronchial dilatation effect is reduced, so the drug may need to be increased to take care.

(3) anticholinergic agents or parasympathetic blockers

In recent years, sympathetic nerve block drugs have been developed to eliminate side effects and have a bronchodilating effect, which is being used in the form of inhalants.

2) Expectorant

Patients with chronic bronchitis often have a high sputum viscosity and are difficult to discharge, making the patient’s symptoms worse. Therefore, to reduce expectoration and to facilitate expectoration, clinically commonly used expectorant is used, but the effect is controversial. It is usually used for the purpose of diluting sticky sputum to facilitate expectoration.

3) Corticosteroids

In the past, it was rarely used in chronic bronchitis, but recently, asthmatic bronchitis has been reported to improve clinical symptoms by corticosteroids.

4) Antibiotics

Use immediately if you suspect an infection. Chronic Bronchitis. Airway bacterial infection is one of the most common causes of exacerbation of airway obstruction. Therefore, proper antibiotic therapy is one of the most important treatments for chronic bronchitis. Purulent sputum usually occurs in airway infections, in which medication should be started in principle.

5) Antitussive

In patients with chronic bronchitis, cough is an important physiological phenomenon that is vital to sustaining life as an important defense mechanism of the human body that is produced to release large amounts of sputum.

Therefore, if possible, it is recommended to avoid excessive use of antitussives in patients with chronic bronchitis. However, if you have a bad cough and can’t sleep, or if you have trouble with daily life or severe hemoptysis, you should relieve your symptoms by taking antitussives (cough medicine) for as long as necessary. The so-called dry cough, which is not accompanied by sputum, is a good indication of antitussive administration.

2. Non-Drug Treatment

1) Exercise / Breath Rehabilitation

While regular physical exercise is controversial, in many cases, exercise therapy can help improve your quality of life, alleviate your symptoms, and help you participate in everyday life, both physically and emotionally.

Patients at any stage can improve endurance, shortness of breath and fatigue with exercise therapy. However, if you have to sit down and live, if you have severe breathing difficulties, or if you are lacking in motivation, it is difficult to expect an effect.

Respiratory therapy is more effective the longer it lasts for at least two months.

(1) exercise training

The patient’s athletic performance can be determined using a bicyclist or treadmill exercise test. An easier way is to measure the distance you walk by adjusting yourself over a period of time.

Exercise training ranges from once daily to weekly, 10 to 45 minutes per hour, intensity from 50% maximum oxygen intake to maximum strength tolerate.

Patients who do not participate in respiratory rehabilitation programs are encouraged to exercise on their own (eg, walk 20 minutes a day).

Arm movements are helpful for people with comorbid conditions that are difficult to do other forms of exercise or for finding respiratory muscle weakness.

(2) nutrition counseling

Nutritional status is an important determinant of symptoms, disorders, and prognosis for people with chronic obstructive pulmonary disease. Both overweight and underweight can be a problem.

In 25% of severe patients, both the Body Mass Index (BMI) and fat free mass are reduced, which is a risk factor for mortality in patients with chronic obstructive pulmonary disease.

2) Respiratory Rehabilitation Treatment

The purpose of rehabilitation is to improve the quality of life, improve breathing difficulties and motor skills, and to increase physical and emotional participation in daily life.

In addition, continued rehabilitation reduces the hospitalization rate due to exacerbation of chronic bronchitis.

3) Oxygen Therapy

In severe cases, hypoxia can develop. In addition, because of the low reserve of pulmonary function, acute respiratory failure often occurs. Therefore, in this case, the first step is to treat hypoxia with oxygen therapy.

The purpose of oxygen therapy is to maintain proper function of vital vital organs by supplying proper oxygen. Proper oxygen administration can increase the survival rate of patients with chronic respiratory failure and reduce the pulmonary artery pressure in the patient, thereby reducing the burden on the heart, and affecting exercise, lung function, and mental well-being.

For patients with chronic hypoxia, continuous oxygen therapy for more than 15 hours a day can increase survival.

3. General Care

The purpose is to prevent deterioration and improve the quality of life.

1) No smoking

Quitting smoking does not immediately improve your lung function. Even if the patient quits smoking, the condition may no longer improve.

Even so, the reason for patients to quit smoking is to prevent further lung or airway damage.

2) Air pollution prevention

3) Water intake

Drinking plenty of fluids is essential to dilute the sputum in people with chronic bronchitis and make it easier to spit out phlegm. At this time, the method of water intake is given by mouth or intravenous injection. The effect is the same. Therefore, drinking as much water as possible is the easiest way to drink water.

4) Posture expectoration

In chronic bronchitis, airway mucus secretion increases with increased airway mucus, resulting in increased sputum.

These sputum, if not discharged, can become a hotbed of secondary bacterial infections, and these sputums themselves can close the airways and deepen breathing difficulties.

If you do not get enough sputum because of coughing, you may want to try sputum.

A common posture for posture sputum is to lower the head and take the sputum naturally down by gravity, usually on an empty stomach.

4. Treatment at exacerbation

Patients with chronic bronchitis symptoms should be actively treated with appropriate treatment if they cause the symptoms to worsen. Among the triggers that make symptoms worse, airway infections, especially viral infections, can be important triggers.

When symptoms worsen with these airway infections, bronchodilators, antibiotics, expectorants, antitussives, and steroids are given. In addition, the sputum sputum is enough to drain the sputum and drink plenty of fluids.

5. Progress and Prognosis

Pulmonary function is reduced by 20 ~ 25cc annually in normal people, but decreases by about 50 ~ 75cc, 2-3 times if you have chronic obstructive pulmonary disease.

When FEV1 is 1.2 ~ 1.5L, respiratory distress occurs during moderate exercise, and when it is below 1L, chronic hypercarbonate, hypoxia, and pulmonary heart are generated. When FEV1 is about 0.5L, it becomes irreversible.

Chronic bronchitis can also be treated with treatment. In particular, if you are exposed to acute infections or other risk factors, aggressive treatment can help prevent illness from getting worse.


When chronic bronchitis is irreversibly shifted to chronic obstructive pulmonary disease, temporary improvement of symptoms can be expected by treatment, but it is not cured. Therefore, prevention of chronic bronchitis is the most important.

In other words, prevention of chronic bronchitis includes smoking cessation and air pollution prevention, frequent airway infection caution and early treatment, and pneumonia and flu shots.

1. No smoking and prevention of air pollution

In reality, preventing air pollution is difficult to practice from a personal standpoint. However, smoking cessation is very important in preventing chronic bronchitis. In particular, even if you do not smoke, the risk of chronic bronchitis is increased by the smoke of other people, so you should try to raise the level of interest in second-hand smoke socially and prepare a countermeasure at the public level.

2. Attention and Early Treatment of Frequent Airway Infections

Frequent airway infections are a major cause of chronic bronchitis. Particular attention should be paid to proper antibiotic treatment and expectoration for airway cleansing to prevent airway histological damage.

Avoid crowded places, especially those with respiratory infections.

If you have symptoms of an infection, you should see your doctor right away and try to get the right treatment and get better soon.

3. Vaccinations against pneumonia and flu

If an indication is given to a patient, frequent airway infections should be prevented by getting a vaccine against pneumonia and flu.

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