3.04 Pathophysiology of COPD.pdf

Pathophysiology of Airways Dysfunction in COPD Dr.Bader J Alghamdi , MD Consultant in Pulmonary Medicine, Section Head of Respirology Director of fellowship Training program-Respirology Assistant Professor KSAU-HS -Jeddah Outlines Introduction...

Pathophysiology of Airways Dysfunction in COPD Dr.Bader J Alghamdi , MD Consultant in Pulmonary Medicine, Section Head of Respirology Director of fellowship Training program-Respirology Assistant Professor KSAU-HS -Jeddah Outlines Introduction Pathology of COPD Physiological disturbance in COPD Diagnosis of COPD Definition Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous lung condition characterized by chronic respiratory symptoms (dyspnea, cough, sputum production and/or exacerbations) due to abnormalities of the airways (bronchitis, bronchiolitis) and/or alveoli (emphysema) that cause persistent, often progressive, airflow obstruction 20123 Global Initiative for Chronic Obstructive Lung Disease  How common is it ? COPD prevalence rates are widely variable Global prevalence is 11.7% (95% CI 8.4%–15.0%) ►Prevalence of COPD is higher in smokers and ex-smokers compared to non-smokers ►Higher ≥ 40 year group compared to those < 40 ►Higher in men than women 2018 Global Initiative for Chronic Obstructive Lung Disease How common is it ? BREATHE Study Respiratory Medicine (2012) 106(S2), S3–S15 How common is it ? BREATHE Study Respiratory Medicine (2012) 106(S2), S3–S15 Clinical COPD is just the Tip of the iceberg  What do you think the % of undertreated COPD in US ? ~ 65 % !!! Symptomatic COPD: Natural History? 100 Never smoked or not I COPD susceptible to smoke FEV1 (% of value at age 25) 75 Susceptible II smoker Dyspnea 50 Activity III restriction Disability 25 IV Death 0 25 50 75 Age (years) Fletcher C, Peto R. Br Med J 1977;1:1645-8.  Top 10 causes of death worldwide IHD Stroke LRTI COPD is the 3rd COPD leading cause of Lung ca death in 2020 !! DM Dementias Diarrhea TB MVA WHO report 2018 Factors that influence disease development and progression Image result for wood fire and copd Image result for bukhoor 2018 Global Initiative for Chronic Obstructive Lung Disease Factors that influence disease development and progression 2017 Global Initiative for Chronic Obstructive Lung Disease Factors that influence disease development and progression Cigarette smoking: 30% of smoker have COPD 90% of COPD are smokers Greater annual reduction of FEV1 than non-smoker Most common RF for COPD Pipe, water pipe, cigar and marijuana are also RF for COPD Passive smoker RF for COPD Smoking during pregnancy poses a rise risk for the fetus by altering lung development 2017 Global Initiative for Chronic Obstructive Lung Disease Factors that influence disease development and progression ► Genetic factors ► Age and gender ► Lung growth and development ► Exposure to particles ► Socioeconomic status ► Asthma & airway hyper-reactivity ► Chronic bronchitis ► Infections 2018 Global Initiative for Chronic Obstructive Lung Disease Airflow limitation in COPD Image result for MECHANISM OF AIRFLOW LIMITATION IN COPD Alpha one antitrypsin deficiency  COPD Chronic bronchitis: Cough and sputum production for at least 3 months in each of two consecutive years in albescence of other causes of chronic cough “blue bloaters” Emphysema: overinflation of the distal airspaces with destruction of alveolar septa “pink puffers” Airway wall histology  Chronic bronchitis Pathologic features 1. Mucus gland hypertrophy/hyperplasia 2. Mucus plugs 3. Goblet cell hyperplasia 4. Smooth muscle hyperplasia 5. Squamous metaplasia 6. Chronic inflammation 7. Fibrosis The hallmark of Chronic bronchitis is mucus hypersecretion Airflow limitation in COPD 2017 Global Initiative for Chronic Obstructive Lung Disease Barnes PJ. N Engl J Med 2000;343:269-280  Emphysema Pathologic features Permanent enlargement of airspaces distal to the terminal bronchioles, emphysema creates an environment leading to a dramatic decline in the alveolar surface area available for gas exchange. Types of Emphysema  Types of Emphysema Centriacinar emphysema - The destruction is limited to the central part of the lobule - Usually affects the upper lobes first then spread down with the progression of the disease - More common in smoker Panacinar emphysema: - The destruction of the whole lobe - Usually affect the lower lobes - Common in alpha one antitrypsin deficiency  Pathogenesis of emphysema - Excessive amounts of the enzyme elastase are released from the neutrophils in the lung - This lead to destruction of elastin and collagen type IV - Cigarette smoking stimulate the neutrophil to release elastase and Reduce the activity of elastase inhibitors - Alpha one antitrypsin deficiency cause lack of antiprotease that normally inhibit elastase Chronic Bronchitis Emphysema COPD ( ACO ) Asthma Airflow limitation  Diagnosis of COPD EXPOSURE TO RISK SYMPTOMS FACTORS cough tobacco sputum occupation shortness of breath indoor/outdoor pollution SPIROMETRY Spirometry Lung volumes and capacities Spirometry: Obstructive Disease 5 Normal 4 Volume, liters 3 FEV1 = 1.8L 2 FVC = 3.2L Obstructive 1 FEV1/FVC = 0.56 1 2 3 4 5 6 Time, seconds Lung Volumes in COPD Normal COPD X PL.V PL.V Increased airways resistance Reduced lung recoil Reduced tethering Expiratory flow limitation Air trapping  Conclusions COPD is characterized by persistent airflow limitation It has two main phenotypes : emphysema and chronic bronchitis Emphysema characterized by destruction in alveolar wall Chronic bronchitis hallmark is mucus hypersecretion Spirometry is mandatory to diagnose COPD Thanks