Chapt. 7: Asthma Flashcards
Common but complex clinical syndrome affecting people of all ages, characterized by variable airflow obstruction, bronchial hyperresponsiveness and airway inflammation, and manifesting as differing phenotypes.
Asthma
Burden of disease of asthma?
Affects 300million individuals of all ages worldwide, comprising 1-18% of the population in different countries
Are fundamental to the definition of asthma, but are rarely measured in primary care?
Airway inflammation and Bronchial Hyperresponsiveness
Used to demonstrate the presence and reversibility of airflow obstruction, and patient-held peak expiratory flow (PEF) meters can be used to show variable airflow obstruction over a period of time (eg. 2-4 weeks)
Spirometry
The principal mechanism of asthma and the main treatment target.
Airway inflammation
Typical features of airway inflammation in asthma?
Increased eosinophils, mast cells, and lymphocytes and predominance of type 2 helper T lymphocytes (Th2 cells).
What is produced by Th2 cells?
IL-3, IL-4, IL-5, IL-13 and GM-CSF
What phenotype of asthma exhibits only few inflammatory cells?
pauci-granulocytic phenotype
What characterizes asthma?
Structural changes in the airway that may precede the development of asthma, including epithelial damage, subepithelial fibrosis, increased airway vasculature, and increased smooth muscle mass.
Mucous hypersecretion is associated with what?
With an increase in the number of secretory glands and goblet cells
What is the prevalence of asthma?
3-5% in developing countries to >20% in developed countries, affecting people of all ages
Allergic type asthma is frequently accompanied by what other manifestations of allergy?
Allergic rhinitis and atopic dermatitis
Of asthma sufferers, what percentage of patients have their first episode of wheezing before 6 years of age?
95%
Adult onset asthma, which is more common in women, is associated with what? (3)
More persistent airflow obstruction, a lack of association with atopy, a worse prognosis.
Asthma common male or female?
Asthma is more common in boys than girls, but more common in women than men, the gender switch occurring in adolescence.
How many people die from asthma each year?
250000 deaths each year, accounting for 1 in every 250 deaths worldwide
What is the incidence of adult onset asthma?
4.6 cases per 1000 person-years in females and 3.6 in males
What is often used to define asthma?
Wheezing at any time in the previous 12 months
Chronic inflammation in asthma is accompanied by structural changes referred to as what?
Remodeling
At least what proportion of patients with asthma have features of allergy, consituting allergic or extrinsic asthma, usually accompanied by elevated levels of circulating IgE, and usually beginning in childhood?
Two thirds
What is the dominant abnormality in asthma?
Airway inflammation, occuring even in the earliest stages
What are the airway inflammatory cells?
Lymphocytes, plasma cells, mast cells and macrophages, typically associated with eosinophils.
What other cells are seen in asthmatic patients who are also smokers?
Neutrophils
What is exhibited by the cells in allergic asthma?
Th2 profile of cytoking secretion, characterized by production if IL-4, IL-5, IL-9, GM-CSF and IL-1