What are 3 details about asthma?
Asthma is a restrictive inflammatory pulmonary disease that usually first presents during childhood or
adolescence
Asthma is caused by the recursive abnormal immune response of B lymphocytes to one or more allergenic
stimuli resulting in inflammation and IgE-mediated histamine release by mast cells plus infiltration by
eosinophilic immune cells
These reactive cellular processes cause constriction of the upper airways and restriction of air flow both into
and out of the lungs
What are 6 details about the clinical diagnosis of asthma?
Early clinical signs include chronic rhinitis and conjunctivitis, coughing, wheezing, shortness of breath, chest tightness and acute episodes of
respiratory distress provoked by allergenic stimuli, infection, respiratory irritants, exposure to cold air, exercise, emotional stress and drugs
In the asthmatic patient, spirometry testing classically reveals that lung dysfunction is partially reversible by administration of a short-acting beta-
agonist such as albuterol
The pathophysiological effects of asthma are usually localized in the upper airways including the trachea,
bronchi and larger bronchioles
The afflicted upper airway structures are lined by non-ciliated squamous epithelium
A distinction from COPD and many other chronic diseases is that asthma onset occurs more often early
in life and the prevalence declines in adulthood
The prevalence is higher in males during childhood and adolescence, but then becomes higher in females
during adulthood
What are 6 details about the global burden of asthma?
Asthma afflicts females more often than males (190 million versus 168 million prevalent cases)
In contrast, the age-adjusted mortality is higher in males than females (6.7 versus 5.6 per 100,000)
Many asthmatic deaths are due to suboptimal long-term medical care and lack of access to emergency services
during the final attack of status asthmaticus
Relatively high prevalence estimates (>10%) are apparent in the USA, Canada, Great Britain, Australia, Brazil and Peru whereas much lower estimates (<5%) are noted for the large populations of China, India and the Russian Federation
Paradoxically, DALY rates are highest in
underdeveloped nations with low prevalence due to lack of access to long-term therapy and emergency
treatment
Population-based studies have not been conducted in many nations and the global pattern of asthma is far from complete
What are 3 details about the hygiene hypothesis of asthma?
In 1989, a brief report was published by David Strachan suggesting that allergic diseases are prevented by infection in early childhood transmitted by unhygienic exposure to older siblings or acquired prenatally from mothers infected by contact with older children
Strachan noted that the prevalence of hay fever or eczema decreases with increasing number of older siblings and suggested that exposure of younger children to infectious agents already contracted by older children in the family conferred protection against the
development of allergic conditions such as eczema, hay fever and asthma
One proposed mechanism is that early infection may increase the population of T helper lymphocytes of the innate immune system (Th-1 cells) to counterbalance T helper cells of the acquired immune system (Th-2 cells)
What are 4 details about trends in asthma mortality in the USA (1999 - 2015)?
During 1990-2015, 61,815 asthma-related deaths occurred in the USA.
African American women had the highest annual mortality (3.5 per 100,000) and Caucasian men the
lowest (0.9 per 100,000)
Age-adjusted annual mortality decreased by about 43% during this time period (2.1 to 1.2 per 100,000)
Results reflect better management of asthmatic symptoms, particularly in elderly patients
What are 4 details about asthma and positive skin tests?
High levels of individual sensitization responses measured by skin prick or IgE level significantly increase the risk
Meta-analysis of available studies on skin prick testing revealed a striking dose response between the relative
risk of asthma and the number of positive tests
The risk of asthma increases by more than 10-fold for individuals with five or more positive skin test reactions to a variety of common allergens
There is a similar though less dramatic dose response between the risk of asthma and the level of total serum
IgE
What are 2 details about risk factors for asthma?
Combinations of risk factors have been found to significantly heighten the risk of developing asthma
Many asthmatic patients report genetic or familial predisposition coupled with environmental exposure to inhaled substances that provoke allergic reactions or irritate the upper airways
What are 5 details about asthma risk factors?
Asthmatic attacks can be stimulated by a wide variety of allergens and environmental factors
Indoor allergens include tobacco smoke, house dust mites, pet dander, cockroach allergens and biomass
smoke
Outdoor allergens include pollen, mold and motor vehicle exhaust
Infectious agents, particularly respiratory viruses, can stimulate asthmatic attacks
Other agents known to cause asthmatic attacks include chemical irritants in the workplace, cold air, emotional
stress, physical exercise, drugs and drug interactions, and certain foods and food additives
What are 6 details about atopy and asthma?
Atopy refers to the production of specific antibodies belonging to the IgE class of immunoglobulins in
response to common environmental allergens
Allergenic stimuli induce large B lymphocytes of the immune system (known as plasma cells) to synthesize
and release E-type immunoglobulins (IgE)
IgE antibodies in turn activate receptors on the cell membranes of mast cells in the upper airways leading to their release of highly inflammatory substances such as histamines and leukotrienes
Inflamed tissues are infiltrated by macrophages and eosinophilic cells of the immune system that also
elaborate cytokines and actively participate in the inflammatory process
Release of destruction enzymes by these immune cells causes necrosis and shedding of the bronchial
epithelium and secretion of mucin resulting in the development of characteristic mucous plugs of the
disease
Atopy can be assessed by skin prick testing as well as total serum IgE
What are 3 details about environmental tobacco smoke and asthma?
Results of epidemiologic studies provide compelling evidence that environmental tobacco smoke
increases the risk of asthma in children.
Estimates from meta-analyses suggest that maternal smoking increases asthma risk by 60% and household ETS exposure increases the risk by 45%
Some studies suggest that maternal or paternal asthma or hay fever combined with exposure to environmental tobacco smoke synergistically increase the risk of asthma in young children
What are 2 details about respiratory viruses and asthma?
Respiratory viruses have been found to influence the development of childhood asthma
The onset of asthma in children is often preceded by severe infection due to respiratory viruses, particularly respiratory syncytial virus and rhinoviruses
What is 1 detail about food allergies and asthma?
Consistent epidemiologic evidence has accrued suggesting that symptomatic food allergies, particularly to milk, eggs and peanuts, significantly increase the risk of asthma development in children
What are 4 details about asthma and obesity?
Several prospective studies have examined associations between weight gain, obesity and the development of
asthma in children and adults
Children with high body weight either at birth or later in childhood are at increased risk for the subsequent
development of asthma
Results suggest 2 to 3-fold increases in the risk of adult onset asthma in obese adults compared to those of
normal weight
Mechanistically, adipocytes engorged with triglycerides are induced to secrete a variety of inflammatory cytokines (adipokines) that may influence asthma risk
What is 1 detail about asthma and household cleaning products?
Occupational studies have found that asthmatic risk is significantly increased by chronic exposure to aerosolized irritants such as cleaning solvents
What are 5 details about drug-induced asthma?
In some individuals, there is progressive development of chronic rhinitis, asthma, nasal polyposis and hypersensitivity to aspirin
The disorder is often called Samter’s triad
Reactions to aspirin in such patients can produce severe asthma attacks and episodes of anaphylaxis.
Sensitivity to aspirin, ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs) may be largely due to their impact on the biosynthesis of prostaglandins versus leukotrienes
NSAIDs reduce inflammation by specifically inhibiting cyclooxygenase, the rate-limiting enzyme of the prostaglandin cascade, thereby shunting conversion of arachidonic acid to leukotrienes rather than prostaglandins
Exposure of the upper airways to certain leukotrienes, particularly leukotriene B-4, can produce inflammatory responses that lead to the development of asthma
What are 3 details about vaccination and childhood asthma?
In recent years, the prevalence of asthma has risen dramatically throughout the world, most notably in
children of developed countries
Since childhood immunization is routinely practiced in the industrialized world, the emerging burden of
asthma in children has prompted studies of a possible etiologic link with immunization
However, the currently available data from observational studies do not support a link between routine immunization and the risk of asthma
development in childhood
What are 10 details about the genetics of asthma?
Simple inheritance patterns of asthma
susceptibility genes have not been identified
The inheritance of susceptibility genes and their translation to the asthmatic phenotype is that of a complex polygenic disorder
Genetic control of chitinases (enzymes that degrade chitin) may modulate susceptibility in some populations
Chitin is a long-chain polysaccharide that serves as an armor or cell wall for fungi and arthropods, including all crustaceans and insects
Chitin is found in insects known to provoke allergenic responses such as dust mites and cockroaches, and
animal studies have shown that chitinase is a powerful stimulant of allergic reactions and inflammation
Chitinases are produced in humans as an innate immune response to chitin exposure
A specific chitinase protein, YKL-40, has been found to provoke allergic reactions in the US Hutterite
population
The Hutterite population is a small genetically isolated religious community of European descent now residing in South Dakota and other locations in the USA
Individuals of the Hutterite population with asthma or broncho-hyper-responsiveness were found to have
significantly elevated serum levels of the YKL-40 protein compared to subjects without asthma
Genetic variation at the YKL-40 locus may play an important role in determining the risk of asthma
development in response to chitin exposure
What are 3 details about preventing asthma progression: avoidance of environmental tobacco smoke?
Avoidance of exposure to environmental tobacco smoke has been found to reduce the risk of asthma development in children
Studies of asthmatic children with high exposure to environmental tobacco smoke suggest they have approximately twice the risk of experiencing acute exacerbation of attacks compared to those with low
exposure
Results underscore the importance of making sure that asthmatic children avoid any exposure to environmental tobacco smoke
What are 4 details about the management of the asthmatic patient?
In the asthmatic patient, allergenic and environmental triggers of asthmatic attacks and exacerbation of other
symptoms must be avoided
Symptoms can be controlled using maintenance therapy with beta-blockers such as theophylline and albuterol
Inhaled corticosteroids are the preferred class of long-term medications to manage persistent asthma in both children and adults
Inhaled corticosteroids reduce the frequency of asthmatic attacks, improve pulmonary function, improve quality of life, enhance exercise tolerance, and reduce hospitalizations
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Burden of Chronic Disease14
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Cardiovascular Diseases (I)31
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Cardiovascular Diseases (II)33
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Obesity and Diabetes48
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Cancer (I)34
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Cancer (II)36
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Cancer (III)45
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COPD and Asthma35
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COPD16
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Asthma19
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Gout11
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HIV6
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Current Issues/Challenges in CD Control/Prevention15
