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
Asthma Phenotypes:
Type 2 –> ATOPY (exercise-induced, allergic asthma, Aspirin enduced respiratory disease)
Type 1 –> Obesity, smoking-related, comorbities
How is asthma diagnosed?
1) Medical history
Symptoms & severity, history
Precipitating factors
2) Physical Exam
Poor indicator of the degree of airflow obstruction
3) Pulmonary Function Tests
Necessary to establish diagnosis, assess severity and treatment response
FEV1/FVC < 75-80% predicted
4) Other laboratory Tests
In the history section of an asthma diagnosis, sx of asthma are? Is everyone the same?
Intermittent episodes of expiratory wheezing, coughing and dypsnea
Chest tightness and chronic cough in some
No - Asthma is not a Heterogeneous disease
To asses symptoms and severity, ASK:
- Assess Symptoms:
In past 12 months have you had:
a) A sudden severe episode or recurrent episode of coughing, wheezing, chest tightness or SOB?
B) Chest colds that take more than 10 days to get over?
C) Coughing, wheezing, or SOB in a particlar season or time of year
D) Coughing, wheezing, or SOB in certain places or when exposed to certain things
To gauge severity:
- Have you used any meds to help you breathe? If so, how often? Have they helped?
- In past 4 weeks, have you had Coughing, wheezing, or SOB when:
i) At night that has awkaned you
ii) Upon awakening
iii) After running, moderate exercise, or physical activity
In regards to conducting a history, one should also ask about?
Family history of asthma/ allergic conditions
–>Positive patient history for allergic conditions
Precipitating factors/Triggers
–>Ask about precipitating factors, variable between patients
What are some triggers of asthma?
Exercise
a drop in FEV1 of 15% or greater from baseline (pre-exercise value)
Most pts with asthma
Time of Day
Worsening during sleep = nocturnal asthma
Associated with endogenous cortisol secretion and circulating epinephrine
Aero-Allergens
Smoke, fumes, pollen, pollutants, mold
Irritants
Perfumes, air fresheners
Respiratory tract infections
Especially less than 10 years old or viral
Weather
Cold, dry OR hot and humid
Psychological factors
Stress? Esp. during an attack
Hormonal Fluctuations
Gastro-esophageal reflux disease (GERD)
Medications
In regards to medication triggers of asthma, what are some common meds that may precipitate an attack?
Medication history is essential!
ASA/NSAIDS
- precipitate an attack in 20% of adults and 5% of children
- Related to recurrent rhinitis and nasal polyps
Radiocontrast media
Beta-blockers
Sulfites, benzalkonium chloride
What is the disadvantage of a physical exam in asthma?
A disease of exacerbation and remission, so the patient may not have any signs or symptoms at the time of exam
Poor indicator of degree of airway obstruction
What may you observe in a physical exam for asthma?
Expiratory wheezing on auscultation
dry hacking cough
signs of atopy (allergic rhinitis and/or eczema)
What are PFT’s necessary to establish?
Necessary to establish diagnosis, assess severity and treatment response
In spirometry, what is the adult criteria to make a diagnosis?
FEV1 /FVC < 75-80% predicted
12% improvement in FEV1 & at least 200 mL from baseline 15 minutes post quick acting 2-agonist challenge or after course of controller therapy
An alternative PFT to diagnose asthma in adults is:
Alternative: Positive challenge test
Assesses level of bronchial hyper-reactivity
Measures the change in PFTs after inhalation of incremental doses of methacholine or exercise (i.e., stimuli known to elicit airway narrowing)
Asthmatics respond with greater degrees of airflow obstruction then normal subjects, at any given dose
When should a healthcare provider reconsider the diagnosis?
a) Frequent sx but normal FEV1:
b) Few Sx but low FEV1:
Reconsider diagnosis if symptoms and lung function don’t match
Frequent symptoms but normal FEV1 = cardiac disease, lack of fitness
Few symptoms but low FEV1 = poor perception, restricted lifestyle?
A low FEV1 is indicative of…….
Low FEV1 = predictor of exacerbation
After diagnosis, monitoring of profgress should be done when……
At diagnosis and 3-6 months after starting treatment
At least every 1 – 2 years for most adults
More often if high risk and children
What is the preferred test in asthma diagnosis? Why?
Spirometry –> Shows reversibility of airway obstruction
Spirometry ofAsthma Diagnosis in Children (<6) and Adults
Children + Adults:
Reduced FEV1/FVC ratio –> less than lower limit of normal based on age, sex, height, and ethnicity
AND
Children + Adults: Increase in FEV1 after a bronchodilator or after course of controller tx
Children: Greater than or equal to 12%
Adults: Greater than or equal to 12% (and a minimum greater than or equal to 200 mL)
What are some other labratory tests that may be used to diagnose asthma?
CBC, eosinophil count, IgE concentration
Allergy skin tests
Sputum eosinophils
monitoring tool in moderate to severe asthma
Use in addition to standard parameters
Asthma Control: Daytime Sx
< or equal to 2 days/week
Asthma Control: Nightime Sx
< 1 night/week and mild
Asthma Control: Physical Activity
Normal
Asthma Control: Exacerbation
Mild and infrequent
Asthma Control: Abscence from school/work
None
Asthma Control: Need for reliever (SABA or bud/form)
< or = to 2 doses/week
Asthma Control: FEV1 or PEF
> or = to 90% of personal best
Asthma Control: PEF dirunal variation
<10-15%
Asthma Control: Sputum eisonophils
< 2-3%
GINA Asthma Control:
- Daytime sx more than 2x/week
- reliever > 2x/week
- Nighttime sx?
- Activity limitation
None - Well Controlled
1-2 –> Partly Controlled
3 –> uncontrolled
Asthma is considered well-controlled when:
Avoid symptoms during the day and night
Need little or no reliever medication
Have productive, physically active lives
Have normal or near-normal lung function
Avoid serious asthma flare-ups (exacerbations, severe attacks)
Goals of Therapy of Asthma
Prevent asthma-related mortality
Maintain normal activity levels
Prevent daytime and nocturnal symptoms
Maintain normal (or near normal) spirometry
Prevent Exacerbations
Provide optimal pharmacotherapy and avoid side effects
(MENS attitudes suck so everyone panic)
What are the principle sof asthma tx?
Environmental control – limit exposure to triggers
Pharmacologic treatment – reduce the inflammatory process
Appropriate use of inhalation therapy
Regular consultation with certified asthma educator
Graduated approach to therapy
Regular follow-up
Triggers of asthma can be:
Examples:
Endogenous stimuli:
those stimuli generated inside the body
e.g. stress, gastroesophageal reflux disease (GERD), rhinitis
Exogenous stimuli:
those stimuli generated outside the body
e.g. exercise, allergens, irritants
Is environmental control a substitute for avoidance of exposure?
NO
What is immunotherapy? is it effective tx for asthma?
Administration of allergen in progressively higher doses to induce tolerance
Limited role in adults
Must identify and use a single, well defined, clinically relevant allergen
Consider if strict environmental avoidance and pharmacologic intervention have failed
Risk vs benefit
Inconvenient
In asthma, what is the difference between a reliever medication vs. a controller medication?
Reliever Medication
Patient should have on hand and take only when needed (during an attack, episode of shortness of breath or before exercising).
Controller Medication
Prevents asthma attacks and inflammation
Take every day, even if no symptoms
Acts slowly and works over the long-term
Will not help in an acute asthma attack
Relievers in asthma are often……
Short-Acting Beta-adrenergic agonists (SABA)
SABA MOA, Onset, Inflammation, peak Effect:
Selective Beta 2 adrenergic agonists (beta receptors SNS mimic epinephrine - beat-2 smooth muscle relaxation in lungs)
Little effect on late (inflammatory) phase
Onset within 5 minutes
Peak effect on FEV within 30 minutes
SABA Indications:
Prevention of exercise induced or cold air induced bronchospasm
Treatment of intermittent episodes of bronchospasm
In comparison of SABA agents:
a) Structure
b) Selectivity
c) Equipotent Response
Structure determines the selectivity, potency, duration of action and oral activity
Agents vary in selectivity for the various receptors (α1, β1, β2 )
Equipotent doses of all adrenergic agents will produce the same degree of bronchodilation
What are the SABA’s and rank there selective potencies?
Epinephrine (a-4, b1- 4, b2 2)
V
Isoproterenol ( a-0, b1-4, b2-4)
V
Metaproterenol (a-0, b1-3, b2-3)
V
Terbutaline (a-0, b1-1, b2-4)
V
Salbutamol (a-0, b1-1,b2-4)
0=none, 1=low potency, 4 = high potency
Every Insecure Man Talks S***
Describe alpha, beta-1, and beta-2 and there effects when stimulated?
Beta-1 –> Iontropic and choronitorpic effects on heart (renin release, increases HR)
Beta-2 –> Smooth muscle relaxation in lungs, GI tract, uterus,
Alpha-1–>Arterial Smooth muscle contraction and vasoconstriction
Adverse Effects of SABA’s
Tachycardia, palpitations
Skeletal muscle tremor
Nervousness, irritability, insomnia, headache
BP changes
Cardiac arrhythmias
Increased blood glucose
Hypokalemia at high doses
Children: excitement / hyperactivity
Tachyphylaxis - Frequent use ↑tolerance and may ↑morbidity/ mortality
- All have beta-1 activity so expect CV A/E