Obstructive lung disease

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Obstructive lung disease
A video discussing bronchial hyperresponsiveness studies of firefighters involved in rescue efforts after the September 11 attacks
Specialty Pulmonology

Obstructive lung disease is a category of respiratory disease characterized by airway obstruction. Many obstructive diseases of the lung result from narrowing (obstruction) of the smaller bronchi and larger bronchioles, often because of excessive contraction of the smooth muscle itself. It is generally characterized by inflamed and easily collapsible airways, obstruction to airflow, problems exhaling, and frequent medical clinic visits and hospitalizations. Types of obstructive lung disease include asthma, bronchiectasis, bronchitis and chronic obstructive pulmonary disease (COPD). 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. [1] Cystic fibrosis is also sometimes included in obstructive pulmonary disease. [2]

Contents

Types

Asthma

Asthma is an obstructive lung disease where the bronchial tubes (airways) are extra sensitive (hyperresponsive). 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. [3] Asthma causes recurring episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning. [4]

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. [3]

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. [5]

Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), previously 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. [6] This can be measured with breathing devices such as a peak flow meter or by spirometry. Most people with COPD have characteristics of emphysema and chronic bronchitis 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. [7]

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 divided by the forced vital capacity (FEV1/FVC) that is less than 0.7 (or 70%). [8] 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 emphysematous COPD. Hyperinflation can also be seen on a chest X-ray as a flattening of the diaphragm.[ citation needed ]

The most common cause of COPD is cigarette smoking. COPD is a gradually progressive condition and usually only develops after about 20 pack-years of smoking. COPD may also be caused by breathing in other particles and gases.[ citation needed ]

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. [9] 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 in carefully chosen cases. Lung transplantation is also performed for severe COPD in carefully chosen cases. [10]

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.[ citation needed ]

Diagnosis

Diagnosis of obstructive disease requires several factors depending on the exact disease being diagnosed. However one commonality between them is an FEV1/FVC ratio less than 0.7, i.e. the inability to exhale 70% of their breath within one second. [11]

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. [12]

ConditionMain siteMajor changesCausesSymptoms
Chronic bronchitis Bronchus Hyperplasia and hypersecretion of mucus glands Tobacco smoking and air pollutants Productive cough
Bronchiolitis
(subgroup of chronic bronchitis)		BronchioleInflammatory scarring and bronchiolitis obliterans Tobacco smoking and air pollutantsCough, dyspnea
Bronchiectasis Bronchus Dilation and scarring of airwaysPersistent severe infectionsCough, purulent sputum and fever
Asthma Bronchus
  • Smooth muscle hyperplasia
  • Excessive mucus
  • Inflammation
  • Constriction
Immunologic or idiopathic Episodic wheezing, cough, and dyspnea
Unless else specified in boxes then reference is [12]

See also

Related Research Articles

<span class="mw-page-title-main">Alpha-1 antitrypsin deficiency</span> Medical condition

Alpha-1 antitrypsin deficiency is a genetic disorder that may result in lung disease or liver disease. Onset of lung problems is typically between 20 and 50 years of age. This may result in shortness of breath, wheezing, or an increased risk of lung infections. Complications may include chronic obstructive pulmonary disease (COPD), cirrhosis, neonatal jaundice, or panniculitis.

<span class="mw-page-title-main">Bronchiectasis</span> Disease of the lungs

Bronchiectasis is a disease in which there is permanent enlargement of parts of the airways of the lung. Symptoms typically include a chronic cough with mucus production. Other symptoms include shortness of breath, coughing up blood, and chest pain. Wheezing and nail clubbing may also occur. Those with the disease often get lung infections.

<span class="mw-page-title-main">Spirometry</span> Pulmonary function test

Spirometry is the most common of the pulmonary function tests (PFTs). It measures lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. Spirometry is helpful in assessing breathing patterns that identify conditions such as asthma, pulmonary fibrosis, cystic fibrosis, and COPD. It is also helpful as part of a system of health surveillance, in which breathing patterns are measured over time.

<span class="mw-page-title-main">Bronchoconstriction</span> Constriction of the terminal airways in the lungs

Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath.

<span class="mw-page-title-main">Respiratory disease</span> Disease of the respiratory system

Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, influenza, and pharyngitis to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, tuberculosis, acute asthma, lung cancer, and severe acute respiratory syndromes, such as COVID-19. Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.

Airway obstruction is a blockage of respiration in the airway that hinders the free flow of air. It can be broadly classified into being either in the upper airway (UPA) or lower airway (LOA).

<span class="mw-page-title-main">Bronchiolitis obliterans</span> Medical condition

Bronchiolitis obliterans (BO), also known as obliterative bronchiolitis, constrictive bronchiolitis and popcorn lung, is a disease that results in obstruction of the smallest airways of the lungs (bronchioles) due to inflammation. Symptoms include a dry cough, shortness of breath, wheezing and feeling tired. These symptoms generally get worse over weeks to months. It is not related to cryptogenic organizing pneumonia, previously known as bronchiolitis obliterans organizing pneumonia.

Occupational lung diseases comprise a broad group of diseases, including occupational asthma, industrial bronchitis, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases, infections, lung cancer and mesothelioma. These can be caused directly or due to immunological response to an exposure to a variety of dusts, chemicals, proteins or organisms. Occupational cases of interstitial lung disease may be misdiagnosed as COPD, idiopathic pulmonary fibrosis, or a myriad of other diseases; leading to a delay in identification of the causative agent.

Air trapping, also called gas trapping, is an abnormal retention of air in the lungs where it is difficult to exhale completely. It is observed in obstructive lung diseases such as asthma, bronchiolitis obliterans syndrome and chronic obstructive pulmonary diseases such as emphysema and chronic bronchitis.

<span class="mw-page-title-main">Bronchitis</span> Inflammation of the large airways in the lungs

Bronchitis is inflammation of the bronchi in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. Symptoms include coughing up sputum, wheezing, shortness of breath, and chest pain. Bronchitis can be acute or chronic.

A bronchial challenge test is a medical test used to assist in the diagnosis of asthma. The patient breathes in nebulized methacholine or histamine. Thus the test may also be called a methacholine challenge test or histamine challenge test respectively. Both drugs provoke bronchoconstriction, or narrowing of the airways. Whereas histamine causes nasal and bronchial mucus secretion and bronchoconstriction via the H1 receptor, methacholine utilizes the M3 receptor for bronchoconstriction. The degree of narrowing can then be quantified by spirometry. People with pre-existing airway hyperreactivity, such as asthmatics, will react to lower doses of drug.

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. Pulmonary function test demonstrates a decrease in the forced vital capacity.

<span class="mw-page-title-main">Pulmonary function testing</span> Test to evaluate respiratory system

Pulmonary function testing (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity of pulmonary impairment. Pulmonary function testing has diagnostic and therapeutic roles and helps clinicians answer some general questions about patients with lung disease. PFTs are normally performed by a pulmonary function technician, respiratory therapist, respiratory physiologist, physiotherapist, pulmonologist, or general practitioner.

<span class="mw-page-title-main">FEV1/FVC ratio</span> Ratio used in the diagnosis of lung disease

The FEV1/FVC ratio, also called modified Tiffeneau-Pinelli index, is a calculated ratio used in the diagnosis of obstructive and restrictive lung disease. It represents the proportion of a person's vital capacity that they are able to expire in the first second of forced expiration (FEV1) to the full, forced vital capacity (FVC). FEV1/FVC ratio first proposed by E.A. Haensler in 1950. The FEV1/FVC index should not be confused with the FEV1/VC index as they are different, although both are intended for diagnosing airway obstruction. Current recommendations for diagnosing pulmonary function recommend using the modified Tiffeneau-Pinelli index. This index is recommended to be represented as a decimal fraction with two digits after the decimal point.

<span class="mw-page-title-main">Acute exacerbation of chronic obstructive pulmonary disease</span> Medical condition

An acute exacerbation of chronic obstructive pulmonary disease, or acute exacerbations of chronic bronchitis (AECB), is a sudden worsening of chronic obstructive pulmonary disease (COPD) symptoms including shortness of breath, quantity and color of phlegm that typically lasts for several days.

<span class="mw-page-title-main">Chronic obstructive pulmonary disease</span> Lung disease involving long-term poor airflow

Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. GOLD 2024 defined COPD as a heterogeneous lung condition characterized by chronic respiratory symptoms due to abnormalities of the airways and/or alveoli (emphysema) that cause persistent, often progressive, airflow obstruction.

The post bronchodilator test, also commonly referred to as a reversibility test, is a test that utilizes spirometry to assess possible reversibility of bronchoconstriction in diseases such as asthma.

<span class="mw-page-title-main">Emphysema</span> Medical condition

Emphysema is any air-filled enlargement in the body's tissues. Most commonly emphysema refers to the enlargement of air spaces (alveoli) in the lungs, and is also known as pulmonary emphysema.

Asthma-Chronic Obstructive Pulmonary Disease (COPD) Overlap (ACO), also known as Asthma-COPD Overlap Syndrome (ACOS) is a chronic inflammatory, obstructive airway disease in which features of both asthma and COPD predominate. Asthma and COPD were once thought of as distinct entities, however in some, there are clinical features of both asthma and COPD with significant overlap in pathophysiology and symptom profile. It is unclear whether ACO is a separate disease entity or a clinical subtype of asthma and COPD. The pathogenesis of ACO is poorly understood, but it is thought to involve both type 2 inflammation as well as type 1 inflammation. The incidence and prevalence of ACO are not well known. The risk factors for ACO are also incompletely understood, but tobacco smoke is known to be a major risk factor.

References

  1. ↑ National Asthma Education and Prevention Program. Clinical Practice Guidelines. Expert Panel Report 2. Guidelines for the Diagnosis and Management of Asthma. Bethesda, Md: National Heart, Lung, and Blood Institute, National Institutes of Health, US Dept of Health and Human Services; 1997. NIH publication 97-4051.
  2. ↑ Restrepo RD (September 2007). "Inhaled adrenergics and anticholinergics in obstructive lung disease: do they enhance mucociliary clearance?" (PDF). Respir Care. 52 (9): 1159–73, discussion 1173–5. PMID   17716384. Archived from the original (PDF) on 2017-04-10. Retrieved 2008-07-21.
  3. 1 2 "GINA – the Global INitiative for Asthma" . Retrieved 2008-05-06.
  4. ↑ "Asthma". The Lecturio Medical Concept Library. 25 November 2020. Retrieved 1 July 2021.
  5. ↑ "What Is Bronchiectasis?". NHLBI. June 2, 2014. Archived from the original on 10 August 2016. Retrieved 10 August 2016.
  6. ↑ Kleinschmidt, Paul. "Chronic Obstructive Pulmonary Disease and Emphysema" . Retrieved 2008-04-19.
  7. ↑ BTS COPD Consortium (2005). "Spirometry in practice – a practical guide to using spirometry in primary care". pp. 8–9. Archived from the original on 26 August 2014. Retrieved 25 August 2014.
  8. ↑ "GOLD – the Global initiative for chronic Obstructive Lung Disease". Archived from the original on 2011-02-16. Retrieved 2008-05-06.
  9. ↑ "What is chronic obstructive pulmonary disease (COPD)?". Archived from the original on 2008-06-14. Retrieved 2008-04-19.
  10. ↑ Weinberger, Steven (2019). Principles of Pulmonary Medicine. Elsevier. p. 93. ISBN   9780323523714.
  11. ↑ Vogelmeier, Claus F.; Criner, Gerard J.; Martinez, Fernando J.; Anzueto, Antonio; Barnes, Peter J.; Bourbeau, Jean; Celli, Bartolome R.; Chen, Rongchang; Decramer, Marc; Fabbri, Leonardo M.; Frith, Peter; Halpin, David M. G.; López Varela, M. Victorina; Nishimura, Masaharu; Roche, Nicolas (2017-03-01). "Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report. GOLD Executive Summary". American Journal of Respiratory and Critical Care Medicine. 195 (5): 557–582. doi:10.1164/rccm.201701-0218PP. hdl: 10044/1/53433 . ISSN   1073-449X. PMID   28128970.
  12. 1 2 Table 13-2 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology: With STUDENT CONSULT Online Access. Philadelphia: Saunders. ISBN   978-1-4160-2973-1. 8th edition.
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