9/21- Asthma Flashcards
T/F: Mortality rates of asthma have decreased over recent years
True
T/F: Mortality rates of COPD have decreased over recent years
False???
What are some basic characteristics of asthma?
- Chronic inflammatory disorder of the airways
- Associated with increased airway responsiveness leading to recurrent episodes of wheezing, breathlessness, chest tightness, and coughing
- Particularly at night or in the early morning
- Episodes typ associated with widespread but variable airflow obstruction
- Often reversible either spontaneously or with treatment
T/F: There has been a recent increase in asthma prevalence in the past decade?
True; 15% increase
What are the risk factors that lead to asthma development?
- Predisposing Factors
- Causal Factors
- Contributing Factors
Predisposing Factors
- Atopy
- Gender
Causal Factors
- Indoor Allergens: Domestic Mites, Animal Allergens, Cockroach Allergens, Fungi (esp Aspergillus)
- Outdoor Allergens: Pollens, Fungi
- Occupational Sensitizers
Contributing Factors:
- Respiratory Infections
- Small Size at Birth
- Obesity
- Air Pollution: outdoor and indoor pollutants
- Smoking: passive and active
T/F: You can “outgrow” asthma
False
What is the pathogenesis of asthma?
- Starting factors: genetically susceptible host + risk factors (viral infection, smoke exposure, allergen exposure…)
- Hormones; aggravated by nonallergen exposure (irritants like smoke, infections, exhaust)
- Chronic allergen exposure -> chronic symptoms (i.e. congestion) -> established disease
What is the early phase response of asthma?
Allergen-Mediated IgE Cross-linking Triggers Mast Cell Degranulation
- Prostaglandins (CCL2, IL-8)
- Histamine
- Leuokotrienes Results in characteristic asthma airway effects
- Vasodilation, edema, increased mucus
- Recruitment of inflammatory cells
- Bronchospasm
What is the late phase response of asthma?
Allergen Recognition by Mast Cells or T Cells Drives Inflammatory Cell Recruitment and Synthesis of Additional Mediators
- Inflammatory cytokines (IL-4, 5, 13)
- Inflammatory cell recruitment and activation: eosinophil, TH2 cell, basophil, neutrophil
- Increased production of cytokines and inflammatory mediators
Symptoms of chronic asthma:
- Thickened basement membrane
- Epithelial injury
- Increased mucus
- Airway obstruction
- Recruitment of inflammatory cells
- Bronchospasm
Chronic airway inflammation leads to what?
General increase in sensitivity to triggers
- Regular exposure of allergic asthma pts to allergens -> chronic inflammation
- Increases in immune cells in the lung, resulting in additional hypersensitivity
Typical inflammation in asthma involves what cell?
Eosinophilic inflammation
- May involve neutrophils as well (subset; not as common as in COPD)
What is the pathology behind airway obstruction and related symptoms?
- Bronchoconstriction
- Mucus Plugs
- Mucosal Edema
- Inflammatory Cell Infiltration/Activation
What is remodeling in asthma?
- Increased vascularity
- Epithelial cell disruption
- Increased airway smooth muscle mass (hyperplasia)
- Reticular basement membrane thickening
What are the major symptoms of asthma and characteristics of the disease?
Wheezing
- During cold/illness, when laughing/crying, in response to allergens or irritants
Breathlessness
Chest tightness
Cough
- Frequent (esp at night)*
- May be only sign in children
- When laughing/crying or in response to allergens/irritants Likely to occur at night and early in the morning*
Likely to increase with activity and exercise
- Esp during cold weather
*Lowest airflow occurs at night; fluctuation in cortisol levels; GERD may also play a role
What is the differential diagnosis for asthma in pediatric pt?
“Active Airway Disease” used in pediatrics to refer to asthma or one of these other diagnoses (not used in adults)
- Distinguish chronic cough from acute cough, which may correspond to viral infections
- Congenital abnormalities
- Cystic fibrosis
- Gastroesophageal reflux
- Airway obstruction
- Bronchopulmonary dysplasia
- Upper airway noise
- Immunodeficiency
- Congenital heart disease
- Vocal cord dysfunction
What is the differential diagnosis for asthma in adult pts?
- Chronic obstructive pulmonary disease
- Congestive heart failure
- Gastroesophageal reflux
- Mechanical obstruction
- Medication
- Vocal cord dysfunction: more in healthcare fields, more in women, “pseudo-asthma”; may see inspiratory loop abnormality and upper airway symptoms
What are some key differences between the presentation of asthma and COPD?
- Age: asthma presents early in life (often childhood) while COPD onset is in midlife
- Symptoms vary from day to day in asthma but are slowly progressive in COPD
- Timing: night/early morning (acid reflux) Sx in asthma
- Reversability: asthma is largely reversible airflow limitation while COPD is only partially reversible
- Allergic rhinitis and/or eczema may also be present in asthmatics
- Asthmatics may have family history of asthma
- COPD may involve dyspnea during exercise or a long smoking history
What clinical evaluation method is key to the diagnosis of asthma?
Spirometry
- Assess severity of airflow obstruction; symptoms alone are insufficient to determine asthma severity
- Helps rule out restrictive airway disease and may show reversability of asthma
- Confirms home PEFR msmts
What are the expected spirometry results in asthma?
Confirm that there is airflow obstruction and at least partially reversible
- Obstruction: FEV1 under 80% predicted; FEV1/FVC under 70%
- Reversibility: FEV1 OR FVC increases > 12% AND at least 200 mL after using a short-acting inhaled B2 agonist
What are additional tests you can do with asthma (in addition to spirometry) if pt has asthma symptoms but normal/near normal spirometry?
- Assess diurnal variation of peak flow over 1 to 2 weeks
- Refer to a specialist for bronchoprovocation/methacholine, histamine, or exercise; negative test may rule out asthma
What are additional tests if you suspect infection, large airway lesions, heart disease, or obstruction by foreign object?
CXR
What are additional tests if you suspect coexisting COPD, restrictive defect, or central airway obstruction?
- Additional pulmonary fct studies
- Diffusing capacity test
What are additional tests if you suspect other factors that contribute to asthma?
- Allergy tests: skin or in vitro
- Nasal examination
- Gastroesophageal reflux assessment
What are the goals of asthma mgmt?
“ACHIEVE OVERALL ASTHMA CONTROL”
Reduce Impairment
- Symptoms
- Reliever use
- Activity
- Lung infection
Reduce future risk
- Instability/worsening
- Exacerbations
- Loss of lung function
- Adverse effects of medication
