Exercise Induced Bronchoconstriction

Question 1

Explain why elite endurance athletes may be susceptible to the development of exercise-induced bronchoconstriction

Answer 1

Chronic ventilation high in noxious environments
Airway injury-recycling, airway inflammation and structural airway remodelling
Concept supported by higher prevalence in elite swimmers and cold-air athletes

Question 2

Describe the application and difference between direct and indirect bronchoprovocation challenges

Answer 2

Bronchoprovocation challenges are used in clinical practice for the diagnosis of asthma and EIB
Direct challenges act directly on airway smooth muscle independent of inflammation
Indirect challenges cause inflammatory cells to release mediators to provoke airway smooth muscle constriction

Question 3

Define dyspnoea

Answer 3

Unpleasant sensation or uncomfortable perception of breathing or need to breathe

Question 4

What the cause of dyspnoea?

Answer 4

lung disease, cardiac disease, physical deconditioning, iron deficiency and anaemia, infectious disease and musculoskeletal conditions

Question 5

Why is there an increase prevalence of EIB among athletes?

Answer 5

Participation in high intensity exercise in certain environmental situations is implicated in the development of airway pathophysiology
Repeated episodes of exercise hyperonoea when performed in noxious environments has been shown to cause airway injury and subsequent repair of airway epithelium
process of injury-repair cycling results in an increase in airway inflammation, structural airway remodelling and an increase in propensity to bronchoconstriction

Question 6

Describe the pathogenesis of acute exercise hyperpnoea

Answer 6

Dehydration of the airway surface lining
Increase in osmolality of ASL
Water moves from cells to restore ASL
Cell shrinkage of airway cause pro-inflammatory mediator release
Which act on SMC causing contraction
As well as airway cooling
Causing reactive hyperaemia

Question 7

Describe the pathogenesis of chronic, repeated exercise hyperpnoea

Answer 7

Airway injury due to repeated and prolong exposure and mechanical airway stress cause an increase in injury repair cycling which causes
Epithelial cell activation and shedding
Pro-Inflammatory milieu
Smooth muscle and mucous gland proliferation
which leads to
Airway epithelial damage
Loss of protective airway barrier
Structural airway remodelling
leading to an increase in propensity to airway narrowing