Asthma Pathophysiology & Clinical Presentation

Question 1

What is the definition of Asthma?

Answer 1

Heterogenous disease, usually characterized by chronic airway inflammation. It is defined by the history of respiratory symptoms, such as wheeze, shortness of breath, chest tightness and cough, that vary over time and intensity, together with variable airflow

Question 2

What are Endogenous Risk factors for Asthma?

Answer 2

• Genetic predisposition
• Atopy
• Airway hyperresponsiveness
• Gender (greater prevalence in males until 14 y/o)
• Obesity
• Early viral infections

Question 3

What are Environmental Risk Factors for Asthma?

Answer 3

• Indoor allergens ex. dust mites
• Outdoor allergens ex. pollen
• Occupational Sensitizers (300 sensitizing allergens identified)
• Smoking
• Respiratory infections
• Diet

Question 4

Inflammatory cells release what? Which cause what?

Answer 4

Release mediators which cause effects

Question 5

Inflammatory Cells Mast cells function?

Answer 5

• Degranulation after exposure to allergens through an IgE-dependent mechanism
• Results in the release of bronchoconstrictor mediators

Question 6

What are some bronchoconstrictor mediators?

Answer 6

Histamine, prostaglandin D2, leukotrienes, Cytokines, growth factors, neutrophils

Question 7

Inflammatory Cells Macrophages Function?

Answer 7

• Serve as “scavengers” engulfing and digesting bacteria and other foreign materials
• Can release cytokines which initiate a type of inflammatory response

Question 8

Inflammatory Cells Dendritic Cells Function?

Answer 8

• Specialized macrophage-like cells in the airway epithelium
• Take up allergens, process them to peptides, and present them to T lymphocytes in the lymph nodes to stimulate production of Th2 cells. Those with asthma have a higher TH2 cell count

Question 9

Inflammatory Cells Eosinophils Function?

Answer 9

• Release proinflammatory mediators (leukotrienes, granule proteins), cytotoxic mediators, cytokines

Question 10

Inflammatory Cells T Lymphocytes Function?

Answer 10

• Release of specific patterns of cytokines which result in the maintenance of eosinophils and mast cells in the airways

Question 11

Structural Cells Airway Epithelial cells Function?

Answer 11

• Express inflammatory proteins, release cytokines, chemokines, and lipid mediators if physical activation

Question 12

Structural Cells Airway smooth muscle cells Function?

Answer 12

• Express similar inflammatory proteins as airway epithelial cells
  -Show increased proliferation and growth in asthma (more muscle = narrow airway)

Question 13

Structural Cells Endothelial Cells Function?

Answer 13

Recruit inflammatory cells from the circulation into the airway