Asthmaby

Farshid Mokhberi Shahid Beheshti University of Medical Science

Asthma

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.

Definition & Basics of AshtmaAsthma 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

Classification of AsthmaIntrinsic 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

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.

Airway Inflammation in Intrinsic TRIGGER

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INFLAMMATORY RESPONSE

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AIRWAY CHANGES

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RESPIRATORY SYMPTOMS

©2010

Extrinsic Asthma

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

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

Airway RemodelingVascularDilation Edema

SubepithelialFibrosis

EpithelialDamage

Inflammatory Cell

InfiltrationSmooth MuscleHypertrophy

Mucous GlandHypertrophy

Mucus

Subbasement MembraneThickening

©2010

Normal Airway Looking at the Main Carina

Airway During Asthma Exacerbation

Diagnosis

Asthma DiagnosisSymptoms

Medical history

Physical Exam

Treatment

Treatment:Acute:

B2 Agonist: Albuterol (short acting), Salmeterol (long acting)

Bronchodilation

Chronic:

Corticosteroids: Fluticasone

Inhibits multiple inflammatory cytokines

Thank You

Refrenceshttp://www.webmd.com/asthma/guide/default.htm

http://www.asthma.org.uk/

http://www.mayoclinic.com/health/asthma/DS00021

http://www.nhlbi.nih.gov/health/asthma