Question

what is the pathophysiology of asthma?

Answer 1

Asthma is a chronic inflammatory disorder of the lower respiratory tract. It is more common in patients with upper respiratory inflammation.

The common symptoms of asthma are wheezing, cough , chest tightness and breathlessness , it can be seen especially at night or early morning. It is associated with reversible widespread and variable airflow obstruction.

AIRFLOW LIMITATION

it is induced by airway inflammation

1. Bronchoconstriction - it is the contraction of bronchial smooth muscles and it is the response to varoous stimuli , it quickly narrows the airway.
2. Airwsy hyperresponsiveness - an exaggerated bronchoconstrictor response to stimuli
3. Airway edema - as the disease becomes more persistent and inflammation become more progressive , edma, mucus hypersecretion, and formation of inspissated mucus plugs further limit airflow.

REMODELLING

reversibility of airflow limitation may be incomplete in some patients

Persistent changes in airway structure

1. Sub basement fibrosis
2. Hypersecretion of mucus
3. Injury to epithelial cells
4. Hypertrophy of smooth muscles
5. Angiogenesis