What is Chronic Bronchitis?
Bronchitis is the inflammation of the lining of the bronchial tubes. These are airways that carry air to the lungs.
Chronic bronchitis is a type of chronic obstructive pulmonary disorder (COPD) that is characterized by a constant cough lasting for a few months. It also causes shortness of breath, wheezing, low grade fever and tightness of chest.
Bronchitis can also be acute- acute bronchitis is very common and mostly viral. It can develop from viral infections like common cold or other respiratory infections. Most cases resolve without treatment, typically within 10-20 days.
An ongoing inflammation of the lining of the bronchial tubes characterized by cough and mucus production lead to chronic bronchitis. It is a serious condition that requires medical attention.
People of all ages can develop chronic bronchitis, but it occurs more often in those older than 45 years. Women are twice more likely than men to be diagnosed with chronic bronchitis.
It is a type of chronic obstructive pulmonary disease (COPD), in which the airflow to the lungs is obstructed by mucus production. In COPD, breathing becomes obstructed and labored as the lungs become inflamed, damaged or narrowed.
COPD is caused by prolonged exposure to substances that irritate and damage the lining of the lungs.
Tobacco smoking being the main cause, other causes include long-term exposure to environmental pollutants like fumes, dust or certain chemicals and other lung irritants like second-hand smoke and genetic factors.
People with COPD are at increased risk of developing heart disease, lung cancer and a variety of other conditions.
- In the United States of America, the number of people diagnosed with chronic bronchitis in the year 2014 were 8.7 million or 3.6% of the population.
- It is estimated that about 3 million deaths (5% of all deaths) globally were caused by COPD in 2015.
- More than 90% of COPD deaths occur in low and middle income countries.
- The number of deaths from chronic lower respiratory diseases (including asthma) was 46.1 per 100,000 population.
- The air enters through the nose, travels into the lungs through the mouth, larynx and trachea.
- The trachea divides into the left and right bronchus also known as primary bronchus. Each bronchus enters the root of the lung.
- Inside the lung, each bronchus divides to form secondary bronchi.
- Each secondary bronchus then further divides into several tertiary bronchi.
- The tertiary bronchi give rise to many conducting bronchioles, which eventually branch into terminal bronchioles.
- Each terminal bronchiole terminates into small collections of air sacs known as alveoli, which is where the actual exchange of carbon dioxide (CO2) and oxygen occur.
- Oxygen diffuses through the walls of the alveoli into adjacent tiny vessels called capillaries and into their red blood cells.
- The oxygen is then carried by the blood to the body tissues.
Repeated irritation of the lining of the bronchial tubes for long periods causes chronic bronchitis. A few of the main irritants are -
- Smoking- long term smoking is the major cause of the condition. Smoke causes irritation to the tissues of the bronchioles and alveoli and damage to the lining of the lungs. Chronic inflammation leaves the linings scarred. Smoke also destroys the tiny, hair-like projections in the airways called cilia that protect us by clearing out mucus and foreign particles.
- Pollution - inhalation of fumes or dust from the environment that irritate and damage lung and airway tissues causes chronic bronchitis.
- Infections and Allergies- infections or allergies can worsen the symptoms of chronic bronchitis.
The main symptom of chronic bronchitis is a hacking cough which is productive in nature. A productive cough brings up clear, yellowish-gray or greenish mucus (phlegm). This type of cough is called a smoker's cough.
For bronchitis to be chronic it has to last for three months with recurring bouts of cough for at least two years in a row.
Other symptoms are similar to those of the common cold or sinusitis, and may include:
- Wheezing or shortness of breath
- Chest discomfort
- Sore throat
- Runny or blocked nose
- Aches and pains
- Tightness of chest
The most important risk factor for chronic bronchitis is smoking. People who smoke or who live with someone who smokes are at higher risk of both acute bronchitis and chronic bronchitis.
Other factors include:
- Low resistance- older adults, infants, young children and those who have conditions that compromise immunity have more vulnerable to develop bronchitis.
- Exposure to lung-irritants at workplace- working under conditions where lungs are exposed to irritants like chemical fumes, like in coal mining, textile industry, grain handling and livestock farming increase the risk of developing bronchitis.
- Gastric reflux- repeated bouts of severe heartburn can irritate the lining of the throat and increase the likelihood of developing bronchitis.
- Frequent respiratory infections and allergies- recurrent infections like cold and sinusitis especially in individuals who have weak immune systems increase the risk of bronchitis.
- Malnutrition- especially among children, increases the risk of bronchitis.
- Preterm birth-babies born preterm have premature lungs. As a result, they have to undergo long-term oxygen therapy. This therapy can cause lung damage and increase the risk of COPD later in life.
- Having a lung disease- pre-existing lung disease is another risk factor for chronic bronchitis.
The doctor may conduct a thorough physical examination and use a stethoscope to listen closely to your breathing. The doctor inquire about your symptoms and record your medical history. The following tests will then be suggested to make a definite diagnosis.
- Chest X-rays help to rule out other conditions like pneumonia that also causes cough.
- Sputum tests-the mucus that the cough brings is called sputum. The sputum can be tested for whooping cough (pertussis) or other illnesses that could be helped by antibiotics. Sputum can also be tested for signs of allergies.
- Pulmonary function tests or PFTs, measure the function of the lungs. It includes tests like spirometry and lung volume tests to measure lung size and air flow.
- Spirometry is used to assess lung function work by measuring the quantity of air inhaled and exhaled and the rate of exhalation. It requires breathing into a tube attached to a machine called a spirometer. It is used to diagnose respiratory conditions like asthma and chronic obstructive pulmonary disease (COPD).
- Blood gas tests measure how well gases such as oxygen move in and out of blood. They are typically ordered if someone has difficulty breathing or shortness of breath, and when conditions like asthma or chronic obstructive pulmonary disease (COPD) are suspected.
- High Resolution Computed Tomography (HRCT) is a special type of CT scan that provides images of lungs with high-resolution images of your lungs.
The main treatment goal for chronic bronchitis is to relieve symptoms, prevent complications and slow the progression of the disease.
To quit smoking is of prime importance for patients with chronic bronchitis, since using tobacco will only increase the damage to the lungs.
Treatment may include:
- Antibiotics may be given if a bacterial cause is suspected or to ward off secondary bacterial infections.
- Cough medicine- If the cough is very severe and affects sleeping, cough suppressants might be helpful.
- Bronchodilator Medications- Bronchodilators are either inhaled as aerosol sprays or taken orally. They relieve symptoms of chronic bronchitis by relaxing and opening the air passages in the lungs and making breathing easier.
- Steroids- These are inhaled as an aerosol spray. They can help relieve symptoms of chronic bronchitis. Long term use of inhaled steroids can cause side effects, such as weakened bones, high blood pressure, diabetes and cataracts. This may also be prescribed if conditions like asthma and allergies are present.
- Vaccines-Patients with chronic bronchitis should receive a flu shot annually and a pneumonia shot every five to seven years to prevent infections.
- Oxygen Therapy- As a patient's disease progresses, people might find it increasingly difficult to breathe on their own and may require supplemental oxygen. Oxygen comes in various forms and may be delivered with different devices.
There is no method to prevent bronchitis. However, measures can be taken to lower the risk for both acute and chronic bronchitis.
Certain measures are:
- Avoid smoking- Cigarette smoke increases the risk of chronic bronchitis.
- Avoid irritants- Avoid exposure to lung irritants like smoke, fume, dust vapors and air pollutants.
- Vaccination-Acute bronchitis mainly results from viral infections. Getting an annual flu (influenza) shot will help to reduce risk of acute bronchitis. Vaccination also provides protection against other types of lung infection like pneumonia.
- Hygiene- Washing hands regularly or use of hand sanitizers will reduce the exposure to viral or bacterial infection.
- Using surgical mask- It is advisable to wear a surgical mask when visiting crowded places especially if COPD has been diagnosed.
Pulmonary Rehabilitation:Pulmonary rehabilitation includes education, nutrition counseling, learning special breathing techniques, help with quitting smoking and starting an exercise regimen.
Physical activity: Because people with chronic bronchitis find it difficult to engage in physical activity, they may avoid any kind of physical activity. But regular physical activity can actually improve the patient's health and well-being.
Healthy Diet: Follow a healthy diet plan including lots of fresh vegetables and fruits. Diet should be low in saturated,, trans fat and cholesterol.
Regular medications: Take medications regularly as per doctor’s instructions.
Latest Publications and Research on Chronic Bronchitis[Evaluation the Extent of Health Damage Caused by PM2.5 Particulate in Xi'an City]. - Published by PubMed
High exposure mining occupations are associated with obstructive lung disease, National Health Interview Survey (NHIS), 2006-2015. - Published by PubMed
Aerodigestive dysbiosis in children with chronic cough. - Published by PubMed
Characteristics of adult cigarette smokers who "relight" and the effects of exposure to tobacco smoke constituents. - Published by PubMed
Procalcitonin-guided antibiotic therapy algorithms for different types of acute respiratory infections based on previous trials. - Published by PubMed