PATHOPHYSIOLOGY OF AIRWAY OBSTRUCTION

Faisal Yunus

Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Indonesia – Persahabatan Hospital,

Jakarta

Airway obstruction has several mechanisms,depend on its abnormality: - Stridor - Bronchial asthma - Chronic bronchitis - Emphysema - Bronchiectasis - Endobronchial tumour - Tumour that suppress the airway

INTRODUCTION

Key action

STRIDOR

Vocal cord inflammation Trauma Infection ~ Croup ~ Foreign body Paralyse

Tracheal edema Tracheal tumour

BRONCHIAL ASTHMA

Bronchial hyperreactivity Diffuse bronchoconstriction Mediator release Mucosal edema Reversible airway obstruction

Eosinophil

Mast cell

Allergen

Th2 cell

MODERN VIEW OF ASTHMAMODERN VIEW OF ASTHMA

VasodilatationNew vessels

Plasma leakOedema

Neutrophil

Mucushypersecretionhyperplasia

Mucus plug

Macrophage

BronchoconstrictionHypertrophy/hyperplasia

Cholinergic reflex

Epithelial shedding

Subepithelialfibrosis

Sensory nerve activation

Nerve activation

GINA2005

Inflammatory cell infiltration/activation

Mucosal oedemaCellular proliferationEpithelial damageBasement membrane

thickening

BronchoconstrictionBronchial hyper-

reactivityHyperplasia Inflammatory

mediator release

Symptoms\exacerbations

Smooth muscle dysfunction

Airway inflammation

ASTHMA PATHOGENESISASTHMA PATHOGENESIS

AsthmaAsthmaNormalNormal

CHRONIC OBSTRUCTIVE PULMONARY DISEASE ( COPD)

Chronic airway irritation Airway limitation partly reversible Two types : - chronic bronchitis - emphysema

Cigarette smoke

Alveolar macrophage

Neutrophil

PROTEASES

Alveolar wall destruction(Emphysema)

Mucus hypersecretion(Chronic bronchitis)

PROTEASEINHIBITORS

Neutrophil chemotactic factors

CELLULAR MECHANISMS OF COPDCELLULAR MECHANISMS OF COPD

Neutrophil elastaseCathepsins

Matrix metalloproteinases

Cytokines (IL-8)Mediators (LTB4)4 ))

?CD8+

lymphocyte

-

MCP-1

ASTHMASensitizing Agent

COPDNoxious Agent

Asthmatic airway inflammationCD4+ T-lymphocytes

Eosinophils

COPD airway inflammationCD8+ T-lymphocytes

MacrophagesNeutrophils

Completely Airflow limitation Completely reversible irreversible

GOLD 2005

INFLAMMATION DIFFERENT BETWEEN COPD AND ASTHMA

Eur Respir J 2003

Inflammation profile different between asthma and COPD

Thorac Soc 2004

Normal Alveolar Emptying

Alveolar Emptying in COPD

In COPD, airflow is limited because alveoli lose their elasticity, supportive structures are lost, and small airways are narrowed

Breathing in the Normal State

Breathing in COPD

Flow–Volume Loops in the Normal State

Flow–Volume Loops in COPD

Chronic Bronchitis

Chronic irritation: - Tobacco smoke - Indoor air polution - Outdoor air polution Mucosal membrane hypertrophy Mucosal membrane hyperplasia Mucosal gland hypersecretion - Reid index

Emphysema

Chronic irritation: - Tobacco smoke - Indoor air polution - Outdoor air polution Abnormal dilatation of the airway distal from terminal bronchiolus Loss elasticity of the lung ( elastic recoil)

Bronchiectasis

Abnormal dilatation of medium bronchus: - chronic infection - airway obstruction - congenital abnormality - Kartagener syndrome Abnormal airflow - turbulence

BRONCHIECTASIS

Lung Tumour

Bronchial tumour obstructs the airway Tumour may supress the airway

PANCOAST TUMOR

Lung Cancer

CONCLUSION

Airway obstruction has several mechanisms, its pathophysiology depends on its abnormality