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OBSTRUCTIVE AIRWAY DISEASE Airways - obstructive disease Lungs - restrictive disease

OBSTRUCTIVE AIRWAY DISEASE Airways - obstructive disease Lungs - restrictive disease Obstructive airway syndrome  Asthma  Chronic bronchitis  Emphysema. OBSTRUCTIVE AIRWAY DISEASE Terminology Early onset / late onset Atopic / non-atopic Extrinsic / Intrinsic. The asthma triad.

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OBSTRUCTIVE AIRWAY DISEASE Airways - obstructive disease Lungs - restrictive disease

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  1. OBSTRUCTIVE AIRWAY DISEASE • Airways - obstructive disease • Lungs - restrictive disease • Obstructive airway syndrome •  Asthma •  Chronic bronchitis •  Emphysema

  2. OBSTRUCTIVE AIRWAY DISEASE • Terminology • Early onset / late onset • Atopic / non-atopic • Extrinsic / Intrinsic

  3. The asthma triad Reversible Airflow Obstruction Airway Inflammation Asthma Airway Hyperresponsiveness

  4. Dynamic evolution of asthma Chronic airway inflammation Broncho- constriction Airway remodeling fixed airway obstruction Brief symptoms exacerbations BHR

  5. Hallmarks of Remodeling in asthma Basement Membrane Submucosa Smooth Muscle Thickening Collagen Deposition Hypertrophy

  6. THE INFLAMMATORY CASCADE Genetic predisposition + Trigger factor • Avoidance (e.g. viral, allergen, chemicals) Airway inflammation • Anti-inflammatory - corticosteroid Mediators • Anti-leukotriene (e.g. histamine, leukotriene) Antihistamine Twitchy smooth muscle • Bronchodilators (Hyper-reactivity) - 2-agonists

  7. The “Tip” of the Iceberg Symptoms/ Exacerbations TITANIC TITANIC Airflow obstruction Bronchial hyperresponsiveness Airway inflammation

  8. Severe asthma –alive Epithelial shedding Severe asthma –autopsy Mucus plugging Normal

  9. Ask about triggers Symptoms can occur or worsen in the presence of: Allergens • animal dander • dust mites • pollen • fungi • Others • exercise • viral infection • smoke • changes in temperature • chemicals • drugs (NSAIDs, ß-blockers)

  10. ASTHMA - THE CLINICAL SYNDROME • Episodic symptoms and signs • Diurinal variability – nocturnal/early morning • Non-productive cough, wheeze • Triggers • Associated atopy ( rhinitis , conjunctivitis, eczema) • Family history of asthma • Wheezing due to turbulent airflow

  11. DIAGNOSIS OF ASTHMA • History and examination • Diurinal variation of peak flow rate • Reduced forced expiratory ratio • (FEV1/FVC < 75%) • Reversibility to inh. salbutamol (>15%) • Provocation testing  bronchospasm • - exercise • - histamine/allergen inhalation

  12. High socioeconomic impact of COPD • 1.5 million GP consultations in the UK per year • 24 million lost working days in the UK per year Economic impactper year • Direct NHS costs – £486 million2 • Additional indirect costs – £1.5 billion (1995)2

  13. Inflammation Mucociliary dysfunction TissueDamage Development of obstruction and ongoing disease progression COPD -A multicomponent disease process Noxious particles or gases, e.g. smoking • Characteristics of the disease: • Exacerbations • Reduced lung function Symptoms: • Breathlessness • Worsening quality of life

  14. - Protease inhibitors Disease processes in COPD Cigarette smoke ? CD8+ lymphocyte Alveolar macrophage Neutrophil chemotatic factors, cytokines (IL-8), mediators (LTB4), oxygen radicals Neutrophil Proteases mucus hypersecretion (chronic bronchitis) Alveolar wall destruction (emphysema) Progressive airflow limitation

  15. Mucociliary function in the healthy state mucus

  16. Damage to the respiratory mucosa due to bacterial infection Healthy H. influenzae

  17. Destruction of the Alveoli Normal Emphysema

  18. Chronic neutrophilic inflammation Mucus hypersecretion Smooth muscle spasm and hypertrophy Partially reversible Alveolar destruction Impaired gas exchange Loss of bronchial support Irreversible COPD Emphysema Chronic Bronchitis

  19. PROTEASE IMBALANCE IN EMPHYSEMA Smoking Genetic Protease Antiprotease Alveolar Destruction Emphysema

  20. COPD -THE CLINICAL SYNDROME • Chronic symptoms - not episodic • Smoking • Non-atopic • Daily productive cough • Progressive breathlessness • Frequent infective exacerbations • Chronic bronchitis- wheezing • Emphysema- reduced breath sounds

  21. CHRONIC CASCADE IN COPD • Progressive fixed airflow obstruction • Impaired alveolar gas exchange • Respiratory failure: PaO2 PaCO2 • Pulmonary hypertension • Right ventricular hypertrophy/failure • (i.e. cor pulmonale) • Death • Stopping smoking arrests further decline in lung volume

  22. Non smokers Allergic Early or late onset Intermittent symptoms Non productive cough Non progressive Eosinophilic inflammation Diurnal variability Good corticosteroid response Good bronchodilator response Preserved FVC and TLCO Normal gas exchange Smokers Non allergic Late onset Chronic symptoms Productive cough Progressive decline Neutrophilic inflammation No diurnal variability Poor corticosteroid response Poor bronchodilator response Reduced FVC and TLCO Impaired gas exchange Asthma vs COPD

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