SM_176a: Asthma

Question 1

Asthma is a ______ disease characterized pathologically by chronic airway ______

Answer 1

Asthma is a heterogeneous disease characterized pathologically by chronic airway inflammation

Question 2

The two hallmarks of asthma are _____ and _____

Answer 2

The two hallmarks of asthma are variability in lung function and reversibility

(variable expiratory airflow limitation, reversible)

Question 3

Asthma prevalence is higher among

• ____ than ____
• ____ than ____
• ____ than ____
• ____ than ____

Answer 3

Asthma prevalence is higher among

• children than adults
• boys than girls
• women than men
• African Americans than Caucasians

Question 4

Burden of asthma is greater in _____, _____, and _____

Answer 4

Burden of asthma is greater in low-income populations, minorities, and children living in inner cities

Question 5

Describe the factors that influence asthma development

Answer 5

• Host factors (predispose individuals to developing asthma): genetic (atopy, airway hyper-responsiveness), gender, obesity
• Environmental factors (influence susceptibility to development of asthma in predisposed individuals, precipitate asthma exacerbations, and/or cause symptoms to persist): indoor allergens, outdoor allergens, occupational sensitizers, tobacco smoke, air pollution, respiratory infections, dust

Question 6

Atopy is ______

Answer 6

Atopy is the body’s predisposition to develop IgE in response to exposure to environmental allergens

(allergic rhinitis, asthma, hay fever, and eczema)

Question 7

Asthma is characterized by ____ type inflammation and primarily involves ____ and ____

Answer 7

Asthma is characterized by T_H2 type inflammation and primarily involves mast cells and eosinophils

Question 8

Describe the steps in IgE synthesis related to asthma

Answer 8

1. T_H2 cells release IL-4, IL-5, and IL-13
2. Activate B cells to release IgE
3. IgE crosslink on mast cells
4. Mast cells become activated and release histamine, leukotrienes, and cytokines
5. Early response: bronchospasm, edema, airflow obstruction
6. Late response: airway inflammation, airflow obstruction, airway hyperresponsiveness

Question 9

Asthma is an ______ lung disease

Answer 9

Asthma is an eosinophilic lung disease

Question 10

Describe the pathophysiology of eosinophil involvement in asthma

Answer 10

1. T_H2 cells and mast cells release IL-5 (and other cytokines)
2. Activate eosinophils
3. Eosinophils release cytokines, leukotrienes, and granule proteins
4. Airway remodeling: goblet cell hyperplasia, new vessel angiogenesis, smooth muscle cell hypertrophy / hyperplasia, and subepithelial fibrosis

Question 11

What are the 4 major pathobiological changes that occur in asthma?

Answer 11

Major pathobiological changes in asthma

• Subepithelial fibrosis
• Smooth muscle cell hypertrophy / hyperplasia
• New vessel angiogenesis
• Goblet cell hyperplasia

Question 12

Which is normal and which is asthma?

Answer 12

Left is normal

Right is asthma

Question 13

Describe inflammation and remodeling in asthma

Answer 13

• Acute response: bronchoconstriction, edema, secretions, cough
• Chronic inflammation: cell recruitment, epithelial damage, early structural changes
• Airway remodeling: cellular proliferation (smooth muscle hypertrophy, goblet cell hyperplasia), increased matrix protein deposition, basement membrane thickening, angiogenesis

Question 14

What are the symptoms of asthma?

Answer 14

• Recurrent episodes of wheezing
• Troublesome cough at night
• Cough or wheeze after exercise
• Cough, wheeze, or chest tightness after exposure to airborne allergens or pollutants
• Colds go to the chest or take more than 10 days to clear

Question 15

How do you establish the diagnosis of asthma?

Answer 15

• Appropriate clinical history: atopic history
• Obstructive physiology on spirometry which improves after a bronchodilator: obstruction may be present sometimes and not others, bronchodilator response may be present sometimes and not others
• Airways hyperreactivity on bronchoprovocation testing: methacholine bronchoprovocation is sensitive but not specific

(clinical diagnosis and objective assessments of symptoms)

Question 16

Describe the appearance of asthma on spirometry

Answer 16

• Volume-time curves: lower than normal
• Flow-volume: scooped out / concave

Question 17

FEV₁ decreases ____ in asthmatics than healthy people on methacholine bronchoprovacation

Answer 17

FEV₁ decreases more in asthmatics than healthy people on methacholine bronchoprovacation

Question 18

People are classified as having persistent asthma if they have any one of the following criteria: ______, ______, ______, ______, ______, or ______

Answer 18

People are classified as having persistent asthma if they have any one of the following criteria:

• Albuterol use > 2 days / week
• Asthma symptoms > 2 days / week
• Nighttime awakenings > 2 times / month
• Minor limitations of normal activity
• 2 or more exacerbations per year

(symptoms and exacerbations guide severity, not lung function, so can have persistent asthma even if FEV₁ > 80%)

Question 19

The main line asthma controller medication is ______

Answer 19

The main line asthma controller medication is inhaled corticosteroids

(never give inhaled bronchodilator without inhaled corticosteroid)

Question 20

The most common asthma rescue medication is _____

Answer 20

The most common asthma rescue medication is rapid-acting inhaled beta-2 agonists (albuterol, salbutamol)

Question 21

Asthma exacerbations are treated with _____ and _____

Answer 21

Asthma exacerbations are treated with repetitive administration of rapid-acting inhaled beta-2 agonist and early introduction of systemic glucorticoids (prednisone, methylprednisone)

(also oxygen supplementation if low O₂ due to V/Q mismatch)

(monitor response to treatment with peak flow and spirometry)