Question

Is Exercise induced asthma temporary or permanent?! please cite your work! thanks

Answer 1

Exercise-induced asthma or better-known exercise-induced bronchoconstriction is a condition characterized by bronchospasm induced by exercise.

Exercise-induced bronchoconstriction (EIB) is a preferred term because:

1. Exercise doesn't cause asthma
2. Exercise-induced bronchoconstriction is also seen in a subset of patients without asthma.

Pathophysiology of EIB

Exercise causes loss of water from the airways. This trigger the following effects

1. Thermal effect
   1. Exercise causes vasoconstriction in the airways
   2. later, quick warming and hyperemia
2. Osmotic effect
   1. Loss of water from the airways causes an increase in the osmolarity of the airway
   2. This triggers the release of various inflammatory mediators. These are nitric oxide, leukotrienes, histamine, and tryptase.
   3. They cause bronchospasm.

Symptoms of EIB

A certain group of people has higher incidence of EIB

1. Elite athletes ( winter sports > summer sports)
2. Ice rink athletes
3. Footballers
4. Swimmers
5. Runners

The symptoms of EIB are similar to asthma. However, they typically occur after the initiation of exercise.

1. breathlessness
2. Wheezing ( audible sound hear while the patient exhales)
3. Cough (dry)
4. Chest tightness

Diagnosis of EIB

1. Lung functions are measured after exercise
2. The parameter studied is Forced expiratory volume at end of 1 sec (FEV1)
3. FEV1 is measured before and after 30mins of exercise.
4. The change/fall in FEV1 is expressed as a percentage
5. Formula - Pre(exercise)FEV1 - Post(exercise)FEV1 * 100

Pre(exercise)FEV1

If the fall in FEV1 is more than or equal to 10% = EIB is diagnosed

Treatment options:

• Non - Pharmacological
  • Wearing masking while exercising in cold weather
  • warmup exercises before the actual training
  • Weight reduction
• Pharmacological therapy
  • 1st line - Short-acting beta-agonist
  • 2nd line - Inhaled corticosteroids + leukotriene inhibitors ( montelukast)
  • 3rd line - Inhaled corticosteroids + mast cell stabilizers (sodium cromoglycate)
  • if the patient has allergies add antihistaminics (levocetirizine)

Prognosis in patients with EIB

With treatment, the prognosis is good

Usually, EIB in asthmatic is permanent. But is managable with treatment