week 5- Asthma Flashcards
who is asthma most prevalent in
kids (males)
then in adults (less common, but female)
low income and urban minority (i.e. Puerto Rican)
definition of asthma according to GINA Global Strategy for Asthma Management and Prevention Report
A heterogenous disease characterized by chronic airway inflammation resulting in airflow limitation
definition of asthma according to National Asthma Education and Prevention Program’s Expert Panel Report:
“A chronic inflammatory disease of the airways in which many cells and cellular elements play a role, including mast cells, eosinophils, neutrophils, T lymphocytes, macrophages, and epithelial cells.” “In susceptible individuals, this inflammation causes recurrent episodes of wheezing, breathlessness, chest tightness, and cough, particularly at night and/or in the early morning. These episodes are usually associated with widespread but variable airflow limitation that is often reversible either spontaneously or with treatment.”
3 characteristics of airway in asthma
- Variable airway obstruction or airflow limitation
- Airway hyperresponsiveness
- Airway inflammation
timing of asthma
recurrent, intermittent, episodic
chronic
worse at night or early morning
flares and exacerbations
endogenous risk factors of asthma
- Atopy
- Airway hyperresponsiveness
- Ethnicity
- Gender
- Genetic predisposition
environmental risk factors for asthma
- Allergens – indoor (pet dander, mites, cockroaches); outdoor (fungi, pollens)
- Obesity
- Occupational sensitizers
- Parasitic infections
- Respiratory infections (early childhood, viral)
- Socioeconomic status
- Tobacco smoking (active and passive)
- Premature birth and low birth weight
- Vitamin D deficiency
- Low intake of omega-3 fatty acids
microbial influence in asthma (protective and risk factors)
protective: microbial diversity, farm animal exposure, vaginal birth, innate immune stimulation, gut mucosa (T reg cells from SCFA)
risk: caesarean birth, gut microbes (clostridium, bifida…), lung microbes (m. catarrhalis, influenza, penumoniae….), airway mucosal (bronchial, Th17 and Th2 infilirate), gut mucosa (IgA, iNKT)
most common trigger of asthma
respiratory infections (acute respiratory tract viral infections such as rhinovirus infections)
exacerbating factors of asthma
respiratory infections (most common)
* Allergens (house dust mites, animal dander, cockroach, indoor fungi/mold, perennial allergens, and seasonal pollens)
* Weather changes (cold air, thunderstorms)
* Drugs (ACE inhibitors, aspirin, beta-blockers, NSAIDs)
* Comorbidities: chronic rhinosinusitis, food allergy, GERD, obesity, pregnancy
* Psychological difficulties, socioeconomic issues
* Exercise and hyperventilation
* Extreme emotional expression (laughing, hard crying, stress)
* Irritants (household sprays, paint fumes, perfumes, organophosphates)
* Sulfur dioxide and pollutant gases
* Tobacco smoking
* Poor adherence to inhaler medications and/or incorrect inhaler technique
2 types of asthma based on atopy
- atopic (extrinsic) asthma
- nonatopic (intrinsic) asthma
what is more common; atopic (extrinsic asthma) or nonatopic (intrinsic) asthma?
atopic
non atopic= 10%
what is the suspected etiologic factor of atopic (extrinsic) asthma
allergens
atopic (extrinsic) asthma and the role of allergens
exagerate immune response: IgE activation and mast cell degradation
comorbid with other atopic diseases (i.e. seasonal allergic rhinitis, allergic conjunctivitis, atopic dermatitis)
common features of nonatopic (intrinsic) asthma
later onset (adult)
more severe + persistent sx
more sensitive to aspirin
nasal polyps common
4 phenotypes of asthma
- Early-onset mild allergic asthma
- Early-onset allergic moderate to severe remodeled asthma
- Late-onset nonallergic eosinophilic asthma
- Late-onset noneosinophilic nonallergic asthma
endotype definition
Endotypes are groups defined by divergent molecular and immunologic mechanisms
2 main end-types of asthma
- T2-high asthma end-types (type 2 asthma)
- T2- low asthma end-types (non-type 2 asthma)
T2-high asthma endotypes (aka type 2 asthma) has which levels of which cytokines
high levels of Th2 cytokines such as IL-4, IL-5, IL-13
T2-low asthma endotypes (aka non-type 2 asthma) has which levels of which cytokines
low levels of Th2 cytokines such as IL-4, IL-5, IL-13
has Th1, Th17, IL-6, IL-8, IL-1B, IFNy
type 2 vs non type 2 asthma cytokines
type 2= high levels
non type 2= low levels
examples of type 2 vs non type 2 asthma
type 2:
* Allergic asthma
* Late-onset T2-high asthma
* Aspirin/NSAID-induced respiratory disease
* Exercise-induced asthma
non-type 2:
* Very late-onset asthma
* Neutrophilic asthma
* Paucigranulocytic asthma
* Obesity-associated asthma
type 2 asthma
-cytokines
-timeline
-other sx
Th2, eosinophils, mast cells, IL-4, IL-5, IL-13
-childhood with other allergic diseases
-with aeroallergen sensitization (immediate asthmatic response to allergy and late asthmatic response)
-sequelae of repeated viral infections
non-type 2 asthma
-cytokines and cells
-timeline
-severity
No type 2 inflammation
-Th1, Th17, IL-6, IL-8, IL-1B, IFN-y
-adults
more severe than type 2