LECTURE: OBSTRUCTIVE & RESTRICTIVE AIRWAY DISEASES WEEK: 3 ASTHMA CLASSIFICATIONS: CAUSES: Chronic bronchial inflammatory disorder characterised by airway obstruction that is: Intermittent Reversible Dysphoea Wheezing Factors that are major contributors to the development of asthma include: Figure 1. Ceel of bronchial free formed from micous sureliuns ouuglied un during an acate sethmalle attana Bronchoconstriction Mucus plugging Breathlessness Chest tightness Cough Genetic predisposition Acute and chronic airway inflammation Bronchial hyper responsiveness Early-phase reaction Bronchoconstriction due to the bronchospasms that causes the tightening of smooth muscles Increased mucus production vasodilation Air trapped in alveoli Relaxed smooth muscle Wall inflamed and thickened Normal airway Late phase reaction Tightened smooth muscle Inflammation Increase in heat Increase in oedema Repeated inflammation can ulcer the structure of the bronchial wall Asthmatic airway during attack Figure 1: Changes in airway due to asthma Hypertrophy of the bronchial smooth muscle CHRONIC OBSTRUCTIVE PULMONARY DISEASE CLASSIFICATIONS A disease state characterised by not Fully reversible chronic bronchial obstruction Obstruction is progressive & associated with abnormal inflammatory response Two different entities Chronic bronchitis Basis of clinical Features Emphysema Basis of morphologic and radiologic Features 100 Never smoked or not susceptible to smoke 75 Smoked regularly and susceptible to the effect Stopped smoking at oge 45 years (% of volum alege 25 years) 50 Onsat of symptoms Stopped smoking at age 65 years 25 Severe disability Death 0 25 50 75 Age (years) Figure 1: Time course of smoking and the changes with smoking cessation COPD CAUSES: Exposure to inhaled noxious gases Cigarette smoke (>90% of cases) Domestic pollutants Burning coal For cooking Genetics (<2% of cases) MANAGEMENT Smoking cessation (stopping) Regular physical activity Prevent respiratory tract infections Breathing retraining Bronchodilators Improve airway diameter Inhaled corticosteroids Reduce inflammation oxygen theraply IF significant hypoxia (PO2 <55mmHg) Goal to achieve haemoglobin- ox oygen saturation of 90
LECTURE: OBSTRUCTIVE & RESTRICTIVE AIRWAY DISEASES WEEK: 3 CLASSIFICATIONS CHRONIC BRONCHITIS CAUSES: Diagnosed clinically In early stages despite the mucus production airFlow is not necessarily obstructed A Mast col Some develop hyperresponsive Parasympathetic norve airways with intermitted Smooth muscle Bronchicles bronchospasms and wheezing Respiratory bronchioles Leads to a build up of CO2 and consequently cyanosis Irritants cause inflammation AirFlow obstruction results From Pulmonary orkery Cortilage Submucosal gand Basement nemtrane Small airway disease, induced by: Mucus plugging of the bronchiolar lumen Inflammation Epithelium Goblet cell Alveol Bronchiolar wall Fibrosis Coexistent emphysema Lack of oxygen Tend to be obese Blue bloaters Mucus accumulation Mucu plug Hyperinflation of alveoli Enlarged submucosal gland Inflammation of epithelium COMPLICATIONS Hypersecretion of mucus in large airwaves by high trophy of mucus glands in the trachea and bronchi Increase in goblet cells in the epithelial surfaces of smaller bronchi and bronchioles CLASSIFICATIONS: EMPHYSEMA CAUSES: Permanent, non-reversible enlargement of the air space by the destruction of alveolar walls without significant Fibrosis Leads to airspace enlargement and decreased alveolar-capillary contact area Cigarette smoke and other noxious particles cause lung damage and inflammation resulting in parenchymal destruction Reduced FEV1 with near normal FVC Adequate gas exchange Dyspnoea and hyperventilation