Asthma Flashcards
Define asthma:
Chronic INFLAMMATORY disorder of the airways characterized by:
1) Paroxysmal or persistent symptoms
2) Dypsnea, chest tightness, wheezing, sputum production & cough
3) Airway hyper-responsiveness to a variety of stimuli
Is Asthma’s course throughout life the same?
Course is variable (fluctuates daily)
Asthma onset:
Onset can occur at any age
What is the #1 chronic condition in Canadian children
?
Childhood asthma is the #1 chronic condition in Canada
15% or children between 4 & 11
8.5% > age 12
Leading cause of ER hospitalizations of children
How many people out of 10 do not have their asthma under control?
6 out of 10 people with asthma do not have control of their condition
How many people die per year of asthma in canada?
250
What is the cause of death of asthma? What % is preventable? How?
- Exacerbations
- Most do not die from long-term progression of asthma
- 80% of these deaths can be prevented with proper education
QOL of Asthmatics
- Can maintain all activities of daily living
- QOL measures can be the same as non-asthmatics
What is the etiology of asthma?
Genetic predisposition and environmental interaction
What % of asthma is genetic? Genes may affect:
- 60-80%
- Multiple genes involved
Genes pre-disposing to atopy
Genes pre-disposing to airway hyper-responsiveness
Genes associated with response to treatment
Which sex has a higher prevalence of asthma?
Childhood: male > female (males have a smaller airway size increasing risk of wheezing)
Around age 20: men = women
> age 40: female> male
What encompasses a genetic predisposition to asthma?
Genes, Sex, Obesity
What is atopy in regards to asthma?
The genetic tendency to develop allergic diseases (IgE mediated) such as allergic rhinitis, asthma and atopic dermatitis (eczema)
- # 1 pre-disposition to asthma
What is the #1 pre-disposing factor to asthma?
ATOPY
What are some examples of environmental factors of asthma?
Smoke
Allergen exposure
Airborne pollens (grass, trees, weeds), house-dust mites, animal danders, cockroaches, fungal spores
Infections in infancy
Respiratory syncytial virus (RSV), decreased exposure to common childhood infectious agents (hygiene hypothesis)
Environment
Cold air, fog, ozone, sulfur dioxide, nitrogen dioxide,tobacco smoke, wood smoke
Occupational sensitizers
Wood dust, chemicals etc.
Exercise
Particularly in cold, dry climate
Drugs/preservatives
Aspirin, NSAIDs (cyclooxygenase inhibitors), sulfites, benzalkonium chloride, non-selective beta-blockers
Diet
ODEE SAID
What are the types of asthma? Explain them? W
Atopic (extrinsic)
- Allergy to antigens - IgE mediated
- Offending allergens are suspended in the air (mainl;y environemntal)
- Family hx of asthma
~1/2 children and young adults (most common - usually begins in childhood)
Non-atopic (intrinsic)
- Non-i,mmune response
- Secondary to chronic/ recurrent infections, pollution, exercise induced, hormonal
- Hypersensitivity to bacteria/ viruses causing infection (MOST COMMOn CULPRIT is VIRUSES)
- No fam hx
- Usually adult onset
Mixed
Asthma (in regards to onset) is primarily diagnosed in ________ and is primarily a ________ disease
Childhood, pediatric
What are some predictors of persistent adult asthma?
Atopy
Onset during school age
Presence of BHR (bronchial hyperreactivity)
What is the pathophysiology of asthma? What is the main hallmark?
Bronchial hyper-reactivity (BHR) of airways to physical, chemical & pharmacologic stimuli is the hallmark of asthma
If anti-inflammatory therapy is not prescribed, airway remodelling can occur
HYPER-REACTIVITY IS THE MAIN HALLMARK
Define bronchospasm. WHat causes it?
Constriction of the muscles in the walls of the bronchioles caused by inflammatory mediators
Define hyper-reactivity. What does it relate to? What dx has the highest hyper-reactivity?
an exaggerated response of bronchial smooth muscles to triggering stimuli
Correlates with clinical course of disease
Hyper-reactivity also seen in allergic rhinitis, chronic bronchitis and CF but not to same extent as asthma
Define airway remodelling. Why do we want to prevent this?
refers to structural changes, including a change in the extracellular matrix in the airway wall leading to airflow obstruction
may eventually become only partially reversible
Highlight the basic pathway of asthma pathophysiology
Asthma (sensitizing agent)
V
Airway Inflammation (CD4+, lymphocytes, eosinophils, mast cells)
V
Airflow limitation (reversible)
Highlight the steps in an asthma response. What occurs in each step? How long does it take each step to occur?
Asthma - Sensitizing Agent
V
Early Asthmatic Response
- occurs in mins
- bronchospasm
-Mast cells –> Histamine
V
Late Asthmatic response
- Occurs in hours
- Bronchospasm returns, submucosal edema, hyper-responsiveness
- Inflammatory cells
V
Chronic Asthma
- occurs in days
- hyper-reactive airways, epithelial cell damage, mucous hyper-secretion
- inflammatory cells
- leads to airway remodelling