Obstructive lung disease
Encyclopedia
Obstructive lung disease is a category of respiratory disease
characterized by airway obstruction
. It is generally characterized by inflamed and easily collapsible airways, obstruction to airflow, and frequent office visits and hospitalizations. Types of obstructive lung disease include; Asthma, Bronchiectasis, Bronchitis, and Chronic obstructive pulmonary disease. Although COPD shares similar characteristics with all other obstructive lung diseases, such as the signs of coughing and wheezing, they are distinct conditions in terms of disease onset, frequency of symptoms and reversibility of airway obstruction. Cystic fibrosis
is also sometimes included in obstructive pulmonary disease but is officially categorized as a restrictive lung disease
.
, which is the ability to exhale 70% of their breath within one second.
). The airways become inflamed and produce excess mucus and the muscles around the airways tighten making the airways narrower. Asthma is usually triggered by breathing in things in the air such as dust or pollen that produce an allergic reaction. It may be triggered by other things such as an upper respiratory tract infection
, cold air, exercise or smoke. Asthma is a common condition and affects over 300 million people around the world.
Asthma causes recurring episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning.
A peak flow meter
can record variations in the severity of asthma over time. Spirometry
, a measurement of lung function, can provide an assessment of the severity, reversibility, and variability of airflow limitation, and help confirm the diagnosis of asthma.
(COPD), also known as chronic obstructive airways disease (COAD) or chronic airflow limitation (CAL), is a group of illnesses characterised by airflow limitation that is not fully reversible. The flow of air into and out of the lungs is impaired. This can be measured with breathing devices such as a peak flow meter
or by spirometry
. The term COPD includes the conditions emphysema
and chronic bronchitis
although most patients with COPD have characteristics of both conditions to varying degrees. Asthma
being a reversible obstruction of airways is often considered separately, but many COPD patients also have some degree of reversibility in their airways.
In COPD, there is an increase in airway resistance
, shown by a decrease in the forced expiratory volume in 1 second (FEV1) measured by spirometry
. COPD is defined as a forced expiratory volume in 1 second to forced vital capacity ratio (FEV1/FVC) that is less than 0.7. The residual volume, the volume of air left in the lungs following full expiration, is often increased in COPD, as is the total lung capacity, while the vital capacity remains relatively normal. The increased total lung capacity (hyperinflation) can result in the clinical feature of a "barrel chest" - a chest with a large front-to-back diameter that occurs in some individuals with COPD. Hyperinflation can also be seen on a chest x-ray
as a flattening of the diaphragm
.
The most common cause of COPD is cigarette smoking
. COPD is a gradually progressive condition and usually only develops after about 20 pack-year
s of smoking. COPD may also be caused by breathing in other particles and gases.
The diagnosis of COPD is established through spirometry
although other pulmonary function tests can be helpful. A chest x-ray
is often ordered to look for hyperinflation and rule out other lung conditions but the lung damage of COPD is not always visible on a chest x-ray
. Emphysema
, for example can only be seen on CT scan
.
The main form of long term management involves the use of inhaled bronchodilators
(specifically beta agonists and anticholinergics) and inhaled corticosteroids
. Many patients eventually require oxygen supplementation
at home. In severe cases that are difficult to control, chronic treatment with oral corticosteroids
may be necessary, although this is fraught with significant side-effects.
COPD is generally irreversible although lung function can partially recover if the patient stops smoking. Smoking cessation is an essential aspect of treatment. Pulmonary rehabilitation programmes involve intensive exercise training combined with education and are effective in improving shortness of breath. Severe emphysema
has been treated with lung volume reduction surgery, with some success in carefully chosen cases. Lung transplantation
is also performed for severe COPD in carefully chosen cases.
Alpha 1-antitrypsin deficiency
is a fairly rare genetic condition that results in COPD (particularly emphysema
) due to a lack of the antitrypsin protein which protects the fragile alveolar walls from protease enzymes released by inflammatory processes
.
Respiratory disease
Respiratory disease is a medical term that encompasses pathological conditions affecting the organs and tissues that make gas exchange possible in higher organisms, and includes conditions of the upper respiratory tract, trachea, bronchi, bronchioles, alveoli, pleura and pleural cavity, and the...
characterized by airway obstruction
Airway obstruction
Airway obstruction is a respiratory problem caused by increased resistance in the bronchioles that reduces the amount of air inhaled in each breath and the oxygen that reaches the pulmonary arteries...
. It is generally characterized by inflamed and easily collapsible airways, obstruction to airflow, and frequent office visits and hospitalizations. Types of obstructive lung disease include; Asthma, Bronchiectasis, Bronchitis, and Chronic obstructive pulmonary disease. Although COPD shares similar characteristics with all other obstructive lung diseases, such as the signs of coughing and wheezing, they are distinct conditions in terms of disease onset, frequency of symptoms and reversibility of airway obstruction. Cystic fibrosis
Cystic fibrosis
Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
is also sometimes included in obstructive pulmonary disease but is officially categorized as a restrictive lung disease
Restrictive lung disease
Restrictive lung diseases are a category of extrapulmonary, pleural, or parenchymal respiratory diseases that restrict lung expansion, resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation...
.
Diagnosis
Diagnosis of obstructive disease requires several factors depending on the exact disease being diagnosed. However one commonalty between them is a decreased FEV1/FVC ratioFEV1/FVC ratio
The FEV1/FVC ratio, also called Tiffeneau index, is a calculated ratio used in the diagnosis of obstructive and restrictive lung disease.It represents the proportion of the forced vital capacity exhaled in the first second....
, which is the ability to exhale 70% of their breath within one second.
Overview table
Following is an overview of the main obstructive lung diseases. Chronic obstructive pulmonary disease is mainly a combination of chronic bronchitis and emphysema, but may be more or less overlapping with all conditions.| Condition | Main site | Major changes | Causes | Symptoms |
|---|---|---|---|---|
| Chronic bronchitis Chronic bronchitis Chronic bronchitis is a chronic inflammation of the bronchi in the lungs. It is generally considered one of the two forms of chronic obstructive pulmonary disease... |
Bronchus Bronchus A bronchus is a passage of airway in the respiratory tract that conducts air into the lungs. The bronchus branches into smaller tubes, which in turn become bronchioles.... |
Hyperplasia and hypersecretion of mucus glands | Tobacco smoking Tobacco smoking Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes... and air pollutants |
Productive cough |
| Bronchiectasis Bronchiectasis Bronchiectasis is a disease state defined by localized, irreversible dilation of part of the bronchial tree caused by destruction of the muscle and elastic tissue. It is classified as an obstructive lung disease, along with emphysema, bronchitis, asthma, and cystic fibrosis... |
Bronchus | Dilation and scarring of airways | Persistent severe infections | Cough, purulent sputum and fever |
| Asthma Asthma Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath... |
Bronchus |
|
Immunologic or idiopathic Idiopathic Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease... |
Episodic wheezing, cough and dyspnea |
| Emphysema Emphysema Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema, the tissues necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called chronic obstructive pulmonary... |
Acinus | Airspace enlargement and wall destruction | Tobacco smoking | Dyspnea |
| Bronchiolitis Bronchiolitis Bronchiolitis is inflammation of the bronchioles, the smallest air passages of the lungs. It usually occurs in children less than two years of age and presents with coughing, wheezing, and shortness of breath. This inflammation is usually caused by viruses... (subgroup of chronic bronchitis) |
Bronchiole | Inflammatory scarring and bronchiole obliteration | Tobacco smoking and air pollutants | Cough, dyspnea |
| Unless else specified in boxes then reference is | ||||
Asthma
Asthma is an obstructive lung disease where the bronchial tubes (airways) are extra sensitive (hyperresponsiveBronchial hyperresponsiveness
Bronchial hyperresponsiveness is a state characterised by easily triggered bronchospasm ....
). The airways become inflamed and produce excess mucus and the muscles around the airways tighten making the airways narrower. Asthma is usually triggered by breathing in things in the air such as dust or pollen that produce an allergic reaction. It may be triggered by other things such as an upper respiratory tract infection
Upper respiratory tract infection
Upper respiratory tract infections are the illnesses caused by an acute infection which involves the upper respiratory tract: nose, sinuses, pharynx or larynx...
, cold air, exercise or smoke. Asthma is a common condition and affects over 300 million people around the world.
Asthma causes recurring episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning.
- Exercise-Indused Asthma — is common in asthmatics, especially after participation in outdoor activities in cold weather.
- Occupational Asthma — An estimated 2% to 5% of all asthma episodes may be caused by exposure to a specific sensitizing agent in the workplace.
- Nocturnal Asthma — is a characteristic problem in poorly controlled asthma and is reported by more than two thirds of sub-optimally treated patients.
A peak flow meter
Peak flow meter
The peak expiratory flow , also called peak expiratory flow rate is a person's maximum speed of expiration, as measured with a peak flow meter, a small, hand-held device used to monitor a person's ability to breathe out air...
can record variations in the severity of asthma over time. Spirometry
Spirometry
Spirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...
, a measurement of lung function, can provide an assessment of the severity, reversibility, and variability of airflow limitation, and help confirm the diagnosis of asthma.
Bronchiectasis
Bronchiectasis refers to the abnormal, irreversible dilatation of the bronchi caused by destructive and inflammatory changes in the airway walls. Bronchiectasis has three major anatomical patterns; cylindrical bronchiectasis, varicose bronchiectasis and cystic bronchiectasis.Chronic obstructive pulmonary disease
Chronic obstructive pulmonary diseaseChronic obstructive pulmonary disease
Chronic obstructive pulmonary disease , also known as chronic obstructive lung disease , chronic obstructive airway disease , chronic airflow limitation and chronic obstructive respiratory disease , is the co-occurrence of chronic bronchitis and emphysema, a pair of commonly co-existing diseases...
(COPD), also known as chronic obstructive airways disease (COAD) or chronic airflow limitation (CAL), is a group of illnesses characterised by airflow limitation that is not fully reversible. The flow of air into and out of the lungs is impaired. This can be measured with breathing devices such as a peak flow meter
Peak flow meter
The peak expiratory flow , also called peak expiratory flow rate is a person's maximum speed of expiration, as measured with a peak flow meter, a small, hand-held device used to monitor a person's ability to breathe out air...
or by spirometry
Spirometry
Spirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...
. The term COPD includes the conditions emphysema
Emphysema
Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema, the tissues necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called chronic obstructive pulmonary...
and chronic bronchitis
Chronic bronchitis
Chronic bronchitis is a chronic inflammation of the bronchi in the lungs. It is generally considered one of the two forms of chronic obstructive pulmonary disease...
although most patients with COPD have characteristics of both conditions to varying degrees. Asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
being a reversible obstruction of airways is often considered separately, but many COPD patients also have some degree of reversibility in their airways.
In COPD, there is an increase in airway resistance
Airway resistance
Airway resistance is a concept used in respiratory physiology to describe mechanical factors which limit the access of inspired air to the pulmonary alveoli, and thus determine airflow....
, shown by a decrease in the forced expiratory volume in 1 second (FEV1) measured by spirometry
Spirometry
Spirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...
. COPD is defined as a forced expiratory volume in 1 second to forced vital capacity ratio (FEV1/FVC) that is less than 0.7. The residual volume, the volume of air left in the lungs following full expiration, is often increased in COPD, as is the total lung capacity, while the vital capacity remains relatively normal. The increased total lung capacity (hyperinflation) can result in the clinical feature of a "barrel chest" - a chest with a large front-to-back diameter that occurs in some individuals with COPD. Hyperinflation can also be seen on a chest x-ray
Chest X-ray
In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...
as a flattening of the diaphragm
Thoracic diaphragm
In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...
.
The most common cause of COPD is cigarette smoking
Smoking
Smoking is a practice in which a substance, most commonly tobacco or cannabis, is burned and the smoke is tasted or inhaled. This is primarily practised as a route of administration for recreational drug use, as combustion releases the active substances in drugs such as nicotine and makes them...
. COPD is a gradually progressive condition and usually only develops after about 20 pack-year
Pack year
-Definition:A way to measure the amount a person has smoked over a long period of time. It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked...
s of smoking. COPD may also be caused by breathing in other particles and gases.
The diagnosis of COPD is established through spirometry
Spirometry
Spirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...
although other pulmonary function tests can be helpful. A chest x-ray
Chest X-ray
In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...
is often ordered to look for hyperinflation and rule out other lung conditions but the lung damage of COPD is not always visible on a chest x-ray
Chest X-ray
In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...
. Emphysema
Emphysema
Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema, the tissues necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called chronic obstructive pulmonary...
, for example can only be seen on CT scan
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
.
The main form of long term management involves the use of inhaled bronchodilators
Bronchodilator
A bronchodilator is a substance that dilates the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the lungs. Bronchodilators may be endogenous , or they may be medications administered for the treatment of breathing difficulties...
(specifically beta agonists and anticholinergics) and inhaled corticosteroids
Glucocorticoid
Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...
. Many patients eventually require oxygen supplementation
Oxygen therapy
Oxygen therapy is the administration of oxygen as a medical intervention, which can be for a variety of purposes in both chronic and acute patient care...
at home. In severe cases that are difficult to control, chronic treatment with oral corticosteroids
Glucocorticoid
Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...
may be necessary, although this is fraught with significant side-effects.
COPD is generally irreversible although lung function can partially recover if the patient stops smoking. Smoking cessation is an essential aspect of treatment. Pulmonary rehabilitation programmes involve intensive exercise training combined with education and are effective in improving shortness of breath. Severe emphysema
Emphysema
Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema, the tissues necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called chronic obstructive pulmonary...
has been treated with lung volume reduction surgery, with some success in carefully chosen cases. Lung transplantation
Lung transplantation
Lung transplantation, or pulmonary transplantation is a surgical procedure in which a patient's diseased lungs are partially or totally replaced by lungs which come from a donor...
is also performed for severe COPD in carefully chosen cases.
Alpha 1-antitrypsin deficiency
Alpha 1-antitrypsin deficiency
Alpha 1-antitrypsin deficiency is an autosomal recessive genetic disorder caused by defective production of alpha 1-antitrypsin , leading to decreased A1AT activity in the blood and lungs, and deposition of excessive abnormal A1AT protein in liver cells...
is a fairly rare genetic condition that results in COPD (particularly emphysema
Emphysema
Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema, the tissues necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called chronic obstructive pulmonary...
) due to a lack of the antitrypsin protein which protects the fragile alveolar walls from protease enzymes released by inflammatory processes
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
.