3. Obstructive & Restrictive Lung Diseases.
Definitions:
Obstructive: Limitation of the airflow usually resulting from an
incraese in resistance due to partial or complete obstruction at
any level. Like: Asthma , Emphysema, Chronic Bronchitis
Restrictive: Reduced expansion of lung parenchyma accompanied
by decreased total lung capacity.
4. Definition & Basics of Ashtma
Asthma is a chronic inflammatory disorder of the airways.
This feature of asthma has implications for the diagnosis,
management, and potential prevention of the disease.
Inflammatory airways disease
Increased responsiveness
Increased contraction of airway smooth muscles
Hypersecretion of bronchial mucus
Altered airway architecture
Altered immunologic state, e.g., atopy
Idiopathic
5. Classification of Asthma
Intrinsic Asthma Extrinsic Asthma
Non-allergic
Usually adult onset
Often follows severe
respiratory illness
More refractory to treatment
Strong family history of allergies
Usually onset at a young age
History of specific allergic
association triggers (e.g. pollen,
animal dander)
Correlation with skin and
inhalation responses to specific
antigens
6. Intrinsic asthma: the absence of atopy
Symptoms are not related to seasons of the year or
identifiable allergens.
Provoked by poorly characterized respiratory tract
infections (viral infection).
Aspirin (nonsteroidal), cold dry air also provoke
asthmatic attacks and are not associated with specific
antibody production.
Once exposed and sensitized, these asthmatic can
develop chronic asthma despite avoidance of sensitizing
chemicals.
Also demonstrate nonspecific bronchial hyperactivity.
10. Airway Inflammation in Extrinsic
Early Phase Response
Involves Type I Hypersensitivity
IgE antibody with Mast Cells
Late Phase Response
Involves Type IV Hypersensitivity
T cell mediated response activates eosinophils, B cells, others
11. Pathophysiology
Airway inflammation
Decreased airway caliber
-Bronchoconstriction-(may cause death on its own)
-Edema of submucosal tissues
-Abnormal airway liquid (mucus plugging)
-Nonspecific hyperreactivity
Air trapping and hyperinflation (CXR and PFTs)
V/Q mismatch compensation occurs during
exacerbations