Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These may occur a few times a day or a few times per week. Depending on the person, they may become worse at night or with exercise.
Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. Diagnosis is usually based on the pattern of symptoms, response to therapy over time, and spirometry. Asthma is classified according to the frequency of symptoms, forced expiratory volume in one second (FEV1), and peak expiratory flow rate. It may also be classified as atopic or non-atopic, where atopy refers to a predisposition toward developing a type 1 hypersensitivity reaction.
There is no cure for asthma. Symptoms can be prevented by avoiding triggers, such as allergens and irritants, and by the use of inhaled corticosteroids. Long-acting beta agonists (LABA) or antileukotriene agents may be used in addition to inhaled corticosteroids if asthma symptoms remain uncontrolled. Treatment of rapidly worsening symptoms is usually with an inhaled short-acting beta-2 agonist such as salbutamol and corticosteroids taken by mouth. In very severe cases, intravenous corticosteroids, magnesium sulfate, and hospitalization may be required.
In 2015, 358 million people globally had asthma, up from 183 million in 1990. It caused about 397,100 deaths in 2015, most of which occurred in the developing world. It often begins in childhood. The rates of asthma have increased significantly since the 1960s. Asthma was recognized as early as Ancient Egypt. The word "asthma" is from the Greek ἅσθμα, ásthma, which means "panting".
|Peak flow meters are used to measure the peak expiratory flow rate, important in both monitoring and diagnosing asthma.|
|Symptoms||Recurring episodes of wheezing, coughing, chest tightness, shortness of breath|
|Causes||Genetic and environmental factors|
|Risk factors||Air pollution, allergens|
|Diagnostic method||Based on symptoms, response to therapy, spirometry|
|Treatment||Avoiding triggers, inhaled corticosteroids, salbutamol|
|Frequency||358 million (2015)|
Asthma is characterized by recurrent episodes of wheezing, shortness of breath, chest tightness, and coughing. Sputum may be produced from the lung by coughing but is often hard to bring up. During recovery from an attack, it may appear pus-like due to high levels of white blood cells called eosinophils. Symptoms are usually worse at night and in the early morning or in response to exercise or cold air. Some people with asthma rarely experience symptoms, usually in response to triggers, whereas others may have marked reactivity and persistent symptoms.
A number of other health conditions occur more frequently in those with asthma, including gastro-esophageal reflux disease (GERD), rhinosinusitis, and obstructive sleep apnea. Psychological disorders are also more common, with anxiety disorders occurring in between 16–52% and mood disorders in 14–41%. However, it is not known whether asthma causes psychological problems or psychological problems lead to asthma. Those with asthma, especially if it is poorly controlled, are at increased risk for radiocontrast reactions.
Asthma is caused by a combination of complex and incompletely understood environmental and genetic interactions. These influence both its severity and its responsiveness to treatment. It is believed that the recent increased rates of asthma are due to changing epigenetics (heritable factors other than those related to the DNA sequence) and a changing living environment. Onset before age 12 is more likely due to genetic influence, while onset after age 12 is more likely due to environmental influence.
Many environmental factors have been associated with asthma's development and exacerbation including allergens, air pollution, and other environmental chemicals. Smoking during pregnancy and after delivery is associated with a greater risk of asthma-like symptoms. Low air quality from factors such as traffic pollution or high ozone levels has been associated with both asthma development and increased asthma severity. Over half of cases in children in the United States occur in areas with air quality below EPA standards. Low air quality is more common in low-income and minority communities.
Exposure to indoor volatile organic compounds may be a trigger for asthma; formaldehyde exposure, for example, has a positive association. Also, phthalates in certain types of PVC are associated with asthma in both children and adults. While exposure to pesticides is linked to the development of asthma, a cause and effect relationship has yet to be established.
There is an association between acetaminophen (paracetamol) use and asthma. The majority of the evidence does not, however, support a causal role. A 2014 review found that the association disappeared when respiratory infections were taken into account. Use by a mother during pregnancy is also associated with an increased risk as is psychological stress during pregnancy.
Asthma is associated with exposure to indoor allergens. Common indoor allergens include dust mites, cockroaches, animal dander (fragments of fur or feathers), and mold. Efforts to decrease dust mites have been found to be ineffective on symptoms in sensitized subjects. Certain viral respiratory infections, such as respiratory syncytial virus and rhinovirus, may increase the risk of developing asthma when acquired as young children. Certain other infections, however, may decrease the risk.
The hygiene hypothesis attempts to explain the increased rates of asthma worldwide as a direct and unintended result of reduced exposure, during childhood, to non-pathogenic bacteria and viruses. It has been proposed that the reduced exposure to bacteria and viruses is due, in part, to increased cleanliness and decreased family size in modern societies. Exposure to bacterial endotoxin in early childhood may prevent the development of asthma, but exposure at an older age may provoke bronchoconstriction. Evidence supporting the hygiene hypothesis includes lower rates of asthma on farms and in households with pets.
Use of antibiotics in early life has been linked to the development of asthma. Also, delivery via caesarean section is associated with an increased risk (estimated at 20–80%) of asthma – this increased risk is attributed to the lack of healthy bacterial colonization that the newborn would have acquired from passage through the birth canal. There is a link between asthma and the degree of affluence which may be related to the hygiene hypothesis as less affluent individuals often have more exposure to bacteria and viruses.
|Endotoxin levels||CC genotype||TT genotype|
|High exposure||Low risk||High risk|
|Low exposure||High risk||Low risk|
Family history is a risk factor for asthma, with many different genes being implicated. If one identical twin is affected, the probability of the other having the disease is approximately 25%. By the end of 2005, 25 genes had been associated with asthma in six or more separate populations, including GSTM1, IL10, CTLA-4, SPINK5, LTC4S, IL4R and ADAM33, among others. Many of these genes are related to the immune system or modulating inflammation. Even among this list of genes supported by highly replicated studies, results have not been consistent among all populations tested. In 2006 over 100 genes were associated with asthma in one genetic association study alone; more continue to be found.
Some genetic variants may only cause asthma when they are combined with specific environmental exposures. An example is a specific single nucleotide polymorphism in the CD14 region and exposure to endotoxin (a bacterial product). Endotoxin exposure can come from several environmental sources including tobacco smoke, dogs, and farms. Risk for asthma, then, is determined by both a person's genetics and the level of endotoxin exposure.
A triad of atopic eczema, allergic rhinitis and asthma is called atopy. The strongest risk factor for developing asthma is a history of atopic disease; with asthma occurring at a much greater rate in those who have either eczema or hay fever. Asthma has been associated with eosinophilic granulomatosis with polyangiitis (formerly known as Churg–Strauss syndrome), an autoimmune disease and vasculitis. Individuals with certain types of urticaria may also experience symptoms of asthma.
There is a correlation between obesity and the risk of asthma with both having increased in recent years. Several factors may be at play including decreased respiratory function due to a buildup of fat and the fact that adipose tissue leads to a pro-inflammatory state.
Beta blocker medications such as propranolol can trigger asthma in those who are susceptible. Cardioselective beta-blockers, however, appear safe in those with mild or moderate disease. Other medications that can cause problems in asthmatics are angiotensin-converting enzyme inhibitors, aspirin, and NSAIDs. Use of acid suppressing medication (proton pump inhibitors and H2 blockers) during pregnancy is associated with an increased risk of asthma in the child.
Some individuals will have stable asthma for weeks or months and then suddenly develop an episode of acute asthma. Different individuals react to various factors in different ways. Most individuals can develop severe exacerbation from a number of triggering agents.
Home factors that can lead to exacerbation of asthma include dust, animal dander (especially cat and dog hair), cockroach allergens and mold. Perfumes are a common cause of acute attacks in women and children. Both viral and bacterial infections of the upper respiratory tract can worsen the disease. Psychological stress may worsen symptoms – it is thought that stress alters the immune system and thus increases the airway inflammatory response to allergens and irritants.
Asthma is the result of chronic inflammation of the conducting zone of the airways (most especially the bronchi and bronchioles), which subsequently results in increased contractability of the surrounding smooth muscles. This among other factors leads to bouts of narrowing of the airway and the classic symptoms of wheezing. The narrowing is typically reversible with or without treatment. Occasionally the airways themselves change. Typical changes in the airways include an increase in eosinophils and thickening of the lamina reticularis. Chronically the airways' smooth muscle may increase in size along with an increase in the numbers of mucous glands. Other cell types involved include: T lymphocytes, macrophages, and neutrophils. There may also be involvement of other components of the immune system including: cytokines, chemokines, histamine, and leukotrienes among others.
While asthma is a well-recognized condition, there is not one universal agreed upon definition. It is defined by the Global Initiative for Asthma as "a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. The chronic inflammation is associated with airway hyper-responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness and coughing particularly at night or in the early morning. These episodes are usually associated with widespread but variable airflow obstruction within the lung that is often reversible either spontaneously or with treatment".
There is currently no precise test for the diagnosis, which is typically based on the pattern of symptoms and response to therapy over time. A diagnosis of asthma should be suspected if there is a history of recurrent wheezing, coughing or difficulty breathing and these symptoms occur or worsen due to exercise, viral infections, allergens or air pollution. Spirometry is then used to confirm the diagnosis. In children under the age of six the diagnosis is more difficult as they are too young for spirometry.
Spirometry is recommended to aid in diagnosis and management. It is the single best test for asthma. If the FEV1 measured by this technique improves more than 12% and increases by at least 200 milliliters following administration of a bronchodilator such as salbutamol, this is supportive of the diagnosis. It however may be normal in those with a history of mild asthma, not currently acting up. As caffeine is a bronchodilator in people with asthma, the use of caffeine before a lung function test may interfere with the results. Single-breath diffusing capacity can help differentiate asthma from COPD. It is reasonable to perform spirometry every one or two years to follow how well a person's asthma is controlled.
The methacholine challenge involves the inhalation of increasing concentrations of a substance that causes airway narrowing in those predisposed. If negative it means that a person does not have asthma; if positive, however, it is not specific for the disease.
Other supportive evidence includes: a ≥20% difference in peak expiratory flow rate on at least three days in a week for at least two weeks, a ≥20% improvement of peak flow following treatment with either salbutamol, inhaled corticosteroids or prednisone, or a ≥20% decrease in peak flow following exposure to a trigger. Testing peak expiratory flow is more variable than spirometry, however, and thus not recommended for routine diagnosis. It may be useful for daily self-monitoring in those with moderate to severe disease and for checking the effectiveness of new medications. It may also be helpful in guiding treatment in those with acute exacerbations.
|Severity||Symptom frequency||Night-time symptoms||%FEV1 of predicted||FEV1 variability||SABA use|
|Mild persistent||>2/week||3–4/month||≥80%||20–30%||>2 days/week|
|Severe persistent||Continuously||Frequent (7/week)||<60%||>30%||≥twice/day|
Asthma is clinically classified according to the frequency of symptoms, forced expiratory volume in one second (FEV1), and peak expiratory flow rate. Asthma may also be classified as atopic (extrinsic) or non-atopic (intrinsic), based on whether symptoms are precipitated by allergens (atopic) or not (non-atopic). While asthma is classified based on severity, at the moment there is no clear method for classifying different subgroups of asthma beyond this system. Finding ways to identify subgroups that respond well to different types of treatments is a current critical goal of asthma research.
Although asthma is a chronic obstructive condition, it is not considered as a part of chronic obstructive pulmonary disease, as this term refers specifically to combinations of disease that are irreversible such as bronchiectasis, chronic bronchitis, and emphysema. Unlike these diseases, the airway obstruction in asthma is usually reversible; however, if left untreated, the chronic inflammation from asthma can lead the lungs to become irreversibly obstructed due to airway remodeling. In contrast to emphysema, asthma affects the bronchi, not the alveoli.
|Near-fatal||High PaCO2, or requiring mechanical ventilation, or both|
(any one of)
|Altered level of consciousness||Peak flow < 33%|
|Exhaustion||Oxygen saturation < 92%|
|Arrhythmia||PaO2 < 8 kPa|
|Low blood pressure||"Normal" PaCO2|
|Poor respiratory effort|
(any one of)
|Peak flow 33–50%|
|Respiratory rate ≥ 25 breaths per minute|
|Heart rate ≥ 110 beats per minute|
|Unable to complete sentences in one breath|
|Peak flow 50–80% best or predicted|
|No features of acute severe asthma|
An acute asthma exacerbation is commonly referred to as an asthma attack. The classic symptoms are shortness of breath, wheezing, and chest tightness. The wheezing is most often when breathing out. While these are the primary symptoms of asthma, some people present primarily with coughing, and in severe cases, air motion may be significantly impaired such that no wheezing is heard. In children, chest pain is often present.
Signs occurring during an asthma attack include the use of accessory muscles of respiration (sternocleidomastoid and scalene muscles of the neck), there may be a paradoxical pulse (a pulse that is weaker during inhalation and stronger during exhalation), and over-inflation of the chest. A blue color of the skin and nails may occur from lack of oxygen.
In a mild exacerbation the peak expiratory flow rate (PEFR) is ≥200 L/min, or ≥50% of the predicted best. Moderate is defined as between 80 and 200 L/min, or 25% and 50% of the predicted best, while severe is defined as ≤ 80 L/min, or ≤25% of the predicted best.
Acute severe asthma, previously known as status asthmaticus, is an acute exacerbation of asthma that does not respond to standard treatments of bronchodilators and corticosteroids. Half of cases are due to infections with others caused by allergen, air pollution, or insufficient or inappropriate medication use.
Brittle asthma is a kind of asthma distinguishable by recurrent, severe attacks. Type 1 brittle asthma is a disease with wide peak flow variability, despite intense medication. Type 2 brittle asthma is background well-controlled asthma with sudden severe exacerbations.
Exercise can trigger bronchoconstriction both in people with or without asthma. It occurs in most people with asthma and up to 20% of people without asthma. Exercise-induced bronchoconstriction is common in professional athletes. The highest rates are among cyclists (up to 45%), swimmers, and cross-country skiers. While it may occur with any weather conditions, it is more common when it is dry and cold. Inhaled beta2-agonists do not appear to improve athletic performance among those without asthma, however, oral doses may improve endurance and strength.
Asthma as a result of (or worsened by) workplace exposures is a commonly reported occupational disease. Many cases, however, are not reported or recognized as such. It is estimated that 5–25% of asthma cases in adults are work-related. A few hundred different agents have been implicated, with the most common being: isocyanates, grain and wood dust, colophony, soldering flux, latex, animals, and aldehydes. The employment associated with the highest risk of problems include: those who spray paint, bakers and those who process food, nurses, chemical workers, those who work with animals, welders, hairdressers and timber workers.
Aspirin-exacerbated respiratory disease (AERD), also known as aspirin-induced asthma, affects up to 9% of asthmatics. AERD consists of asthma, nasal polyps, sinus disease, and respiratory reactions to aspirin and other NSAID medications (such as ibuprofen and naproxen). People often also develop loss of smell and most experience respiratory reactions to alcohol.
Alcohol may worsen asthmatic symptoms in up to a third of people. This may be even more common in some ethnic groups such as the Japanese and those with aspirin-induced asthma. Other studies have found improvement in asthmatic symptoms from alcohol.
Nonallergic asthma, also known as intrinsic or nonatopic asthma, makes up between 10 and 33% of cases. There is negative skin test to common inhalant allergens and normal serum concentrations of IgE. Often it starts later in life, and women are more commonly affected than men. Usual treatments may not work as well.
Many other conditions can cause symptoms similar to those of asthma. In children, other upper airway diseases such as allergic rhinitis and sinusitis should be considered as well as other causes of airway obstruction including foreign body aspiration, tracheal stenosis, laryngotracheomalacia, vascular rings, enlarged lymph nodes or neck masses. Bronchiolitis and other viral infections may also produce wheezing. In adults, COPD, congestive heart failure, airway masses, as well as drug-induced coughing due to ACE inhibitors should be considered. In both populations vocal cord dysfunction may present similarly.
Chronic obstructive pulmonary disease can coexist with asthma and can occur as a complication of chronic asthma. After the age of 65, most people with obstructive airway disease will have asthma and COPD. In this setting, COPD can be differentiated by increased airway neutrophils, abnormally increased wall thickness, and increased smooth muscle in the bronchi. However, this level of investigation is not performed due to COPD and asthma sharing similar principles of management: corticosteroids, long-acting beta-agonists, and smoking cessation. It closely resembles asthma in symptoms, is correlated with more exposure to cigarette smoke, an older age, less symptom reversibility after bronchodilator administration, and decreased likelihood of family history of atopy.
The evidence for the effectiveness of measures to prevent the development of asthma is weak. The World Health Organization recommends decreasing risk factors such as tobacco smoke, air pollution, chemical irritants including perfume, and the number of lower respiratory infections. Other efforts that show promise include: limiting smoke exposure in utero, breastfeeding, and increased exposure to daycare or large families, but none are well supported enough to be recommended for this indication.
Early pet exposure may be useful. Results from exposure to pets at other times are inconclusive and it is only recommended that pets be removed from the home if a person has allergic symptoms to said pet.
Dietary restrictions during pregnancy or when breast feeding have not been found to be effective and thus are not recommended. Reducing or eliminating compounds known to sensitive people from the work place may be effective. It is not clear if annual influenza vaccinations affects the risk of exacerbations. Immunization; however, is recommended by the World Health Organization. Smoking bans are effective in decreasing exacerbations of asthma.
While there is no cure for asthma, symptoms can typically be improved. A specific, customized plan for proactively monitoring and managing symptoms should be created. This plan should include the reduction of exposure to allergens, testing to assess the severity of symptoms, and the usage of medications. The treatment plan should be written down and advise adjustments to treatment according to changes in symptoms.
The most effective treatment for asthma is identifying triggers, such as cigarette smoke, pets, or aspirin, and eliminating exposure to them. If trigger avoidance is insufficient, the use of medication is recommended. Pharmaceutical drugs are selected based on, among other things, the severity of illness and the frequency of symptoms. Specific medications for asthma are broadly classified into fast-acting and long-acting categories.
Bronchodilators are recommended for short-term relief of symptoms. In those with occasional attacks, no other medication is needed. If mild persistent disease is present (more than two attacks a week), low-dose inhaled corticosteroids or alternatively, a leukotriene antagonist or a mast cell stabilizer by mouth is recommended. For those who have daily attacks, a higher dose of inhaled corticosteroids is used. In a moderate or severe exacerbation, corticosteroids by mouth are added to these treatments.
People with asthma have higher rates of anxiety and depression. This is associated with poorer asthma control. Cognitive behavioral therapy may improve quality of life, asthma control, and anxiety levels in people with asthma.
Avoidance of triggers is a key component of improving control and preventing attacks. The most common triggers include allergens, smoke (from tobacco or other sources), air pollution, non selective beta-blockers, and sulfite-containing foods. Cigarette smoking and second-hand smoke (passive smoke) may reduce the effectiveness of medications such as corticosteroids. Laws that limit smoking decrease the number of people hospitalized for asthma. Dust mite control measures, including air filtration, chemicals to kill mites, vacuuming, mattress covers and others methods had no effect on asthma symptoms. Overall, exercise is beneficial in people with stable asthma. Yoga could provide small improvements in quality of life and symptoms in people with asthma.
Medications used to treat asthma are divided into two general classes: quick-relief medications used to treat acute symptoms; and long-term control medications used to prevent further exacerbation. Antibiotics are generally not needed for sudden worsening of symptoms.
Medications are typically provided as metered-dose inhalers (MDIs) in combination with an asthma spacer or as a dry powder inhaler. The spacer is a plastic cylinder that mixes the medication with air, making it easier to receive a full dose of the drug. A nebulizer may also be used. Nebulizers and spacers are equally effective in those with mild to moderate symptoms. However, insufficient evidence is available to determine whether a difference exists in those with severe disease. There is no strong evidence for the use of intravenous LABA for adults or children who have acute asthma.
Long-term use of inhaled corticosteroids at conventional doses carries a minor risk of adverse effects. Risks include thrush, the development of cataracts, and a slightly slowed rate of growth. Higher doses of inhaled steroids may result in lower bone mineral density.
When asthma is unresponsive to usual medications, other options are available for both emergency management and prevention of flareups. For emergency management other options include:
Many people with asthma, like those with other chronic disorders, use alternative treatments; surveys show that roughly 50% use some form of unconventional therapy. There is little data to support the effectiveness of most of these therapies. Evidence is insufficient to support the usage of vitamin C. There is tentative support for its use in exercise induced bronchospasm. In people with mild to moderate asthma, treatment with vitamin D supplementation is likely to reduce the risk of asthma exacerbations.
Acupuncture is not recommended for the treatment as there is insufficient evidence to support its use. Air ionisers show no evidence that they improve asthma symptoms or benefit lung function; this applied equally to positive and negative ion generators.
Manual therapies, including osteopathic, chiropractic, physiotherapeutic and respiratory therapeutic maneuvers, have insufficient evidence to support their use in treating asthma. The Buteyko breathing technique for controlling hyperventilation may result in a reduction in medication use; however, the technique does not have any effect on lung function. Thus an expert panel felt that evidence was insufficient to support its use.
The prognosis for asthma is generally good, especially for children with mild disease. Mortality has decreased over the last few decades due to better recognition and improvement in care. In 2010 the death rate was 170 per million for males and 90 per million for females. Rates vary between countries by 100 fold.
Globally it causes moderate or severe disability in 19.4 million people as of 2004 (16 million of which are in low and middle income countries). Of asthma diagnosed during childhood, half of cases will no longer carry the diagnosis after a decade. Airway remodeling is observed, but it is unknown whether these represent harmful or beneficial changes. Early treatment with corticosteroids seems to prevent or ameliorates a decline in lung function. Asthma in children also has negative effects on quality of life of their parents.
As of 2011, 235–330 million people worldwide are affected by asthma, and approximately 250,000–345,000 people die per year from the disease. Rates vary between countries with prevalences between 1 and 18%. It is more common in developed than developing countries. One thus sees lower rates in Asia, Eastern Europe and Africa. Within developed countries it is more common in those who are economically disadvantaged while in contrast in developing countries it is more common in the affluent. The reason for these differences is not well known. Low and middle income countries make up more than 80% of the mortality.
While asthma is twice as common in boys as girls, severe asthma occurs at equal rates. In contrast adult women have a higher rate of asthma than men and it is more common in the young than the old. In children, asthma was the most common reason for admission to the hospital following an emergency department visit in the US in 2011.
Global rates of asthma have increased significantly between the 1960s and 2008 with it being recognized as a major public health problem since the 1970s. Rates of asthma have plateaued in the developed world since the mid-1990s with recent increases primarily in the developing world. Asthma affects approximately 7% of the population of the United States and 5% of people in the United Kingdom. Canada, Australia and New Zealand have rates of about 14–15%.
The average death rate from 2011 to 2015 from asthma in the UK was about 50% higher than the average for the European Union and had increased by about 5% in that time.
From 2000 to 2010, the average cost per asthma-related hospital stay in the United States for children remained relatively stable at about $3,600, whereas the average cost per asthma-related hospital stay for adults increased from $5,200 to $6,600. In 2010, Medicaid was the most frequent primary payer among children and adults aged 18–44 years in the United States; private insurance was the second most frequent payer. Among both children and adults in the lowest income communities in the United States there is a higher rate of hospital stays for asthma in 2010 than those in the highest income communities.
Asthma was recognized in ancient Egypt and was treated by drinking an incense mixture known as kyphi. It was officially named as a specific respiratory problem by Hippocrates circa 450 BC, with the Greek word for "panting" forming the basis of our modern name. In 200 BC it was believed to be at least partly related to the emotions. In the 12th century the Jewish physician-philosopher Maimonides wrote a treatise on asthma in Arabic, based partly on Arabic sources, in which he discussed the symptoms, proposed various dietary and other means of treatment, and emphasized the importance of climate and clean air.
In 1873, one of the first papers in modern medicine on the subject tried to explain the pathophysiology of the disease while one in 1872, concluded that asthma can be cured by rubbing the chest with chloroform liniment. Medical treatment in 1880 included the use of intravenous doses of a drug called pilocarpine. In 1886, F. H. Bosworth theorized a connection between asthma and hay fever. Epinephrine was first referred to in the treatment of asthma in 1905. Oral corticosteroids began to be used for this condition in the 1950s while inhaled corticosteroids and selective short acting beta agonist came into wide use in the 1960s.
A notable and well-documented case in the 19th century was that of young Theodore Roosevelt (1858–1919). At that time there was no effective treatment. Roosevelt's youth was in large part shaped by his poor health partly related to his asthma. He experienced recurring nighttime asthma attacks that caused the experience of being smothered to death, terrifying the boy and his parents.
During the 1930s to 1950s, asthma was known as one of the "holy seven" psychosomatic illnesses. Its cause was considered to be psychological, with treatment often based on psychoanalysis and other talking cures. As these psychoanalysts interpreted the asthmatic wheeze as the suppressed cry of the child for its mother, they considered the treatment of depression to be especially important for individuals with asthma.
Allergies, also known as allergic diseases, are a number of conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, sneezing, a runny nose, shortness of breath, or swelling. Food intolerances and food poisoning are separate conditions.Common allergens include pollen and certain food. Metals and other substances may also cause problems. Food, insect stings, and medications are common causes of severe reactions. Their development is due to both genetic and environmental factors. The underlying mechanism involves immunoglobulin E antibodies (IgE), part of the body's immune system, binding to an allergen and then to a receptor on mast cells or basophils where it triggers the release of inflammatory chemicals such as histamine. Diagnosis is typically based on a person's medical history. Further testing of the skin or blood may be useful in certain cases. Positive tests, however, may not mean there is a significant allergy to the substance in question.Early exposure to potential allergens may be protective. Treatments for allergies include avoiding known allergens and the use of medications such as steroids and antihistamines. In severe reactions injectable adrenaline (epinephrine) is recommended. Allergen immunotherapy, which gradually exposes people to larger and larger amounts of allergen, is useful for some types of allergies such as hay fever and reactions to insect bites. Its use in food allergies is unclear.Allergies are common. In the developed world, about 20% of people are affected by allergic rhinitis, about 6% of people have at least one food allergy, and about 20% have atopic dermatitis at some point in time. Depending on the country about 1–18% of people have asthma. Anaphylaxis occurs in between 0.05–2% of people. Rates of many allergic diseases appear to be increasing. The word "allergy" was first used by Clemens von Pirquet in 1906.Aspirin exacerbated respiratory disease
Aspirin exacerbated respiratory disease (AERD), also termed aspirin-induced asthma, is a medical condition initially defined as consisting of three key features: asthma, respiratory symptoms exacerbated by aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), and nasal polyps. The symptoms of respiratory reactions in this syndrome are hypersensitivity reactions to NSAIDs rather than the typically described true allergic reactions that trigger other common allergen-induced asthma, rhinitis, or hives. The NSAID-induced reactions do not appear to involve the common mediators of true allergic reactions, immunoglobulin E or T cells. Rather, AERD is a type of NSAID-induced hypersensitivity syndrome. EAACI/WHO classifies the syndrome as one of five types of NSAID hypersensitivity or NSAID hypersensitivity reactions.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 (originating naturally within the body), or they may be medications administered for the treatment of breathing difficulties. They are most useful in obstructive lung diseases, of which asthma and chronic obstructive pulmonary disease are the most common conditions. Although this remains somewhat controversial, they might be useful in bronchiolitis and bronchiectasis. They are often prescribed but of unproven significance in restrictive lung diseases.Bronchodilators are either short-acting or long-acting. Short-acting medications provide quick or "rescue" relief from acute bronchoconstriction. Long-acting bronchodilators help to control and prevent symptoms. The three types of prescription bronchodilating drugs are β2("beta two")-adrenergic agonists (short- and long-acting), anticholinergics (short-acting), and theophylline (long-acting).Cardiac asthma
Cardiac asthma is a medical diagnosis of wheezing, coughing or shortness of breath due to congestive heart failure. It is known as cardiac asthma because the symptoms mimic ordinary asthma (bronchial asthma). One study found that patients with cardiac asthma represented one third of congestive heart failure in elderly patients.Depending on severity, it may be classified as a medical emergency, as it can be a symptom of acute heart failure leading to the buildup of fluid in the lungs (pulmonary edema) as well as within and around the airways.
The distinction between bronchial asthma and cardiac asthma is especially important because some treatments for bronchial asthma, including inhalers, may worsen cardiac asthma or cause severe heart arrhythmias.
Bronchial asthma, in contrast, is caused by the inflammation and narrowing of pulmonary airways, causing the characteristic breathing difficulties. Bronchial asthma has nothing to do with fluid in the lungs or heart disease, or even the heart failure associated with cardiac asthma.Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involved in a wide range of physiological processes, including stress response, immune response, and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte levels, and behavior.Some common naturally occurring steroid hormones are cortisol (C21H30O5), corticosterone (C21H30O4), cortisone (C21H28O5) and aldosterone (C21H28O5). (Note that aldosterone and cortisone share the same chemical formula but the structures are different.) The main corticosteroids produced by the adrenal cortex are cortisol and aldosterone.Eosinophil
Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. Along with mast cells and basophils, they also control mechanisms associated with allergy and asthma. They are granulocytes that develop during hematopoiesis in the bone marrow before migrating into blood, after which they are terminally differentiated and do not multiply.These cells are eosinophilic or "acid-loving" due to their large acidophilic cytoplasmic granules, which show their affinity for acids by their affinity to coal tar dyes: Normally transparent, it is this affinity that causes them to appear brick-red after staining with eosin, a red dye, using the Romanowsky method. The staining is concentrated in small granules within the cellular cytoplasm, which contain many chemical mediators, such as eosinophil peroxidase, ribonuclease (RNase), deoxyribonucleases (DNase), lipase, plasminogen, and major basic protein. These mediators are released by a process called degranulation following activation of the eosinophil, and are toxic to both parasite and host tissues.
In normal individuals, eosinophils make up about 1–3% of white blood cells, and are about 12–17 micrometres in size with bilobed nuclei. While they are released into the bloodstream as neutrophils are, eosinophils reside in tissue. They are found in the medulla and the junction between the cortex and medulla of the thymus, and, in the lower gastrointestinal tract, ovaryes, uterus, spleen, and lymph nodes, but not in the lungs, skin, esophagus, or some other internal organs under normal conditions. The presence of eosinophils in these latter organs is associated with disease. For instance, patients with eosinophilic asthma have high levels of eosinophils that lead to inflammation and tissue damage, making it more difficult for patients to breathe. Eosinophils persist in the circulation for 8–12 hours, and can survive in tissue for an additional 8–12 days in the absence of stimulation. Pioneering work in the 1980s elucidated that eosinophils were unique granulocytes, having the capacity to survive for extended periods of time after their maturation as demonstrated by ex-vivo culture experiments.Exercise-induced bronchoconstriction
Exercise-induced asthma, or E.I.A., occurs when the airways narrow as a result of exercise. The preferred term for this condition is exercise-induced bronchoconstriction (EIB); exercise does not cause asthma, but is frequently an asthma trigger.Feline asthma
Feline asthma is a common allergic respiratory disease in cats, affecting at least one percent of all adult cats worldwide. It is a chronic progressive disease for which there is no cure. Common symptoms include wheezing, coughing, labored breathing and potentially life-threatening bronchoconstriction. There is conjecture that the disease is becoming more common due to increased exposure to industrial pollutants.Metered-dose inhaler
A metered-dose inhaler (MDI) is a device that delivers a specific amount of medication to the lungs, in the form of a short burst of aerosolized medicine that is usually self-administered by the patient via inhalation. It is the most commonly used delivery system for treating asthma, chronic obstructive pulmonary disease (COPD) and other respiratory diseases. The medication in a metered dose inhaler is most commonly a bronchodilator, corticosteroid or a combination of both for the treatment of asthma and COPD. Other medications less commonly used but also administered by MDI are mast cell stabilizers, such as cromoglicate or nedocromil.Nebulizer
In medicine, a nebulizer or nebuliser (see spelling differences) is a drug delivery device used to administer medication in the form of a mist inhaled into the lungs. Nebulizers are commonly used for the treatment of asthma, cystic fibrosis, COPD and other respiratory diseases or disorders.
Analytical nebulizers are another form of nebulizer that is used primarily in laboratory settings for elemental analysis.
Nebulizers use oxygen, compressed air or ultrasonic power to break up solutions and suspensions into small aerosol droplets that can be directly inhaled from the mouthpiece of the device. An aerosol is a mixture of gas and solid or liquid particles.Obstructive lung disease
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. Cystic fibrosis is also sometimes included in obstructive pulmonary disease.Occupational asthma
Occupational asthma refers to new onset asthma or the recurrence of previously quiescent asthma directly caused by exposure to an agent at workplace. It is an occupational lung disease and a type of work-related asthma. Agents that can induce occupational asthma can be grouped into sensitizers and irritants.Sensitizer-induced occupational asthma immunologic form of asthma which occurs due to inhalation of specific substances (i.e., high-molecular-weight proteins from plants and animal origins, or low-molecular-weight agents that include chemicals, metals and wood dusts) and occurs after a latency period of several weeks to years.Irritant-induced (occupational) asthma is a non-immunologic form of asthma that results from a single or multiple high dose exposure to irritant products. It is usually develops early after exposure; however can also develop insidiously over a few months after a massive exposure to a complex mixture of alkaline dust and combustion products, as shown in the World Trade Center disaster. Unlike those with sensitizer-induced occupational asthma, subjects with irritant-induced occupational asthma do not develop work-related asthma symptoms after re-exposure to low concentrations of the irritant that initiated the symptoms. Reactive airways dysfunction syndrome (RADS) is an severe form of irritant induced asthma where respiratory symptoms usually develop in the minutes or hours after a single accidental inhalation of a high concentration of irritant gas, aerosol, vapor, or smoke.Another type of work-related asthma is work-exacerbated asthma (WEA) which is asthma worsened by workplace conditions but not caused by it. WEA is present in about a fifth of patients with asthma and a wide variety of conditions at work, including irritant chemicals, dusts, second-hand smoke, common allergens that may be present at work, as well as other “exposures” such as emotional stress, worksite temperature, and physical exertion can exacerbate asthma symptoms in these patients. Both occupational asthma and work-exacerbated asthma can be present in an individual.
A number of diseases have symptoms that mimic occupational asthma, such as asthma due to nonoccupational causes, chronic obstructive pulmonary disease (COPD), irritable larynx syndrome, hyperventilation syndrome, hypersensitivity pneumonitis, and bronchiolitis obliterans.Omalizumab
Omalizumab, sold under the trade name Xolair, is a medication originally designed to reduce sensitivity to allergens. It has been used to try to control severe allergic asthma, which does not respond to high doses of corticosteroids and less widely for chronic spontaneous urticaria.
Omalizumab is a recombinant DNA-derived humanized IgG1k monoclonal antibody that specifically binds to free human immunoglobulin E (IgE) in the blood and interstitial fluid and to membrane-bound form of IgE (mIgE) on the surface of mIgE-expressing B lymphocytes. Unlike an ordinary anti-IgE antibody, it does not bind to IgE that is already bound by the high affinity IgE receptor (FcεRI) on the surface of mast cells, basophils, and antigen-presenting dendritic cells.Reslizumab
Reslizumab is a humanized monoclonal antibody against human interleukin-5 (IL-5). Reslizumab binds specifically to IL-5, a key cytokine responsible for the differentiation, maturation, recruitment and activation of human eosinophils. By binding to human IL-5, it blocks its biological function; consequently survival and activity of eosinophils are reduced. The benefits with reslizumab are its ability to reduce the exacerbation rate and improve lung function and asthma-related quality of life in patients with severe eosinophilic asthma (with blood eosinophil count ≥ 400 cells/μL) and with at least one previous asthma exacerbation in the preceding year. The most common side effects are increased blood creatine phosphokinase, myalgia and anaphylactic reactions.The FDA approved reslizumab (US trade name Cinqair) for use with other asthma medicines for the maintenance treatment of severe asthma in patients aged 18 years and older on 23 March 2016. Cinqair is approved for patients who have a history of severe asthma attacks (exacerbations) despite receiving their current asthma medicines.The European Medicines Agency recommended the granting of a marketing authorisation for reslizumab (EU trade name Cinqaero) intended as add-on treatment in adult patients with severe eosinophilic asthma on 23 June 2016.Reslizumab is supplied as a refrigerated, sterile, single-use, preservative-free solution for intravenous infusion. The reslizumab solution is a slightly hazy/opalescent, slightly yellow liquid and is supplied as 100 mg in a 10 mL glass vial. Each single-use vial of reslizumab is formulated as 10 mg/mL reslizumab in an aqueous solution containing 2.45 mg/mL sodium acetate trihydrate, 0.12 mg/mL glacial acetic acid, and 70 mg/mL sucrose, with a pH of 5.5.Respiratory therapist
A respiratory therapist is a specialized healthcare practitioner trained in pulmonary medicine in order to work therapeutically with people suffering from pulmonary disease. Respiratory therapists graduate from a community college or university
with a certification in respiratory therapy and have passed a national board certifying examination. The NBRC (National Board for Respiratory Care) is the not-for-profit organization responsible for credentionaling the seven areas of Respiratory Therapy.
Those seven areas of Respiratory Therapy include, as of December 2017: CRT (Certified Respiratory Therapist), RRT (Registered Respiratory Therapist), CPFT and RPFT (Certified or Registered Pulmonary Function Technologist), ACCS (Adult Critical Care Specialist), NPS (Neonatal/Pediatric Specialist), and SDS (Sleep Disorder Specialist).
Respiratory therapists work in hospitals in the intensive care units (Adult, Pediatric, and Neonatal), on hospital floors, in Emergency Departments, in Pulmonay Functioning laboratories (PFTs), are able to intubate patients, work in sleep labs (polysomnograpy) (PSG) labs, and in home care specifically DME (Durable Medical Equipment) and home oxygen.
Respiratory therapists are specialists and educators in many areas including cardiology, pulmonology, and sleep therapy. Respiratory therapists are clinicians trained in advanced airway management; establishing and maintaining the airway during management of trauma, and intensive care.
Respiratory therapists initiate and manage life support for people in intensive care units and emergency departments, stabilizing, treating and managing pre-hospital and hospital-to-hospital patient transport by air or ground ambulance.
In the outpatient setting respiratory therapists work as educators in asthma clinics, ancillary clinical staff in pediatric clinics, and sleep-disorder diagnosticians in sleep-clinics, they also serve as clinical providers in cardiology clinics and cath-labs, as well as working in pulmonary rehabilitation.Rhinitis
Rhinitis, also known as coryza, is irritation and inflammation of the mucous membrane inside the nose. Common symptoms are a stuffy nose, runny nose, sneezing, and post-nasal drip.The inflammation is caused by viruses, bacteria, irritants or allergens. The most common kind of rhinitis is allergic rhinitis, which is usually triggered by airborne allergens such as pollen and dander. Allergic rhinitis may cause additional symptoms, such as sneezing and nasal itching, coughing, headache, fatigue, malaise, and cognitive impairment. The allergens may also affect the eyes, causing watery, reddened, or itchy eyes and puffiness around the eyes. The inflammation results in the generation of large amounts of mucus, commonly producing a runny nose, as well as a stuffy nose and post-nasal drip. In the case of allergic rhinitis, the inflammation is caused by the degranulation of mast cells in the nose. When mast cells degranulate, they release histamine and other chemicals, starting an inflammatory process that can cause symptoms outside the nose, such as fatigue and malaise. In the case of infectious rhinitis, it may occasionally lead to pneumonia, either viral or bacterial. Sneezing also occurs in infectious rhinitis to expel bacteria and viruses from the respiratory tract.
Rhinitis is very common. Allergic rhinitis is more common in some countries than others; in the United States, about 10%–30% of adults are affected annually. Mixed rhinitis (MR) refers to patients with nonallergic rhinitis and allergic rhinitis. MR is a specific rhinitis subtype. It may represent between 50 and 70% of all AR patients. However, true prevalence of MR has not been confirmed yet.Salbutamol
Salbutamol, also known as albuterol and marketed as Ventolin among other names, is a medication that opens up the medium and large airways in the lungs. It is used to treat asthma including asthma attacks, exercise-induced bronchoconstriction, and chronic obstructive pulmonary disease (COPD). It may also be used to treat high blood potassium levels. Salbutamol is usually used with an inhaler or nebulizer but is also available as a pill and intravenous solution. Onset of action of the inhaled version is typically within 15 minutes and lasts for two to six hours.Common side effects include shakiness, headache, fast heart rate, dizziness, and feeling anxious. Serious side effects may include worsening bronchospasm, irregular heartbeat, and low blood potassium levels. It can be used during pregnancy and breastfeeding, but safety is not entirely clear. It is a short-acting β2 adrenergic receptor agonist which works by causing airway smooth muscles to relax.Salbutamol was first made in 1967 in Britain and became commercially available in the UK in 1969. It was approved for medical use in the United States in 1982. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Salbutamol is available as a generic medication. The wholesale cost in the developing world of an inhaler which contains 200 doses is between US$1.12 and US$2.64 as of 2014. In the United States, it is between $25 and $50 for a typical month's supply. In 2016 it was the 10th most prescribed medication in the United States with more than 47 million prescriptions.Salmeterol
Salmeterol is a long-acting β2 adrenergic receptor agonist (LABA) used in the maintenance and prevention of asthma symptoms and maintenance of chronic obstructive pulmonary disease (COPD) symptoms. Symptoms of bronchospasm include shortness of breath, wheezing, coughing and chest tightness. It is also used to prevent breathing difficulties during exercise (exercise-induced bronchoconstriction). It is marketed as Serevent in the US. It is available as a dry powder inhaler that releases a powdered form of the drug. It was previously available as a metered-dose inhaler (MDI) but was discontinued in the US in 2002. It is still available as an MDI in the UK as of 2013.Thunderstorm asthma
Thunderstorm asthma is the triggering of an asthma attack by environmental conditions directly caused by a local thunderstorm. It has been proposed that during a thunderstorm, pollen grains can absorb moisture and then burst into much smaller fragments with these fragments being easily dispersed by wind. However, there is no experimental evidence confirming this theory. While larger pollen grains are usually filtered by hairs in the nose, the smaller pollen fragments are able to pass through and enter the lungs, triggering the asthma attack.