Asthma .pptx
- 2. Definition: Asthma means “laboured breathing”. It is a broad term used to refer to a disorder of the respiratory system that leads to episodic difficulty in breathing.
- 3. The national UK guidelines (BTS/SIGN,2009) define asthma as a “chronic inflammatory disorder of the airways which occur in susceptible individuals; inflammatory symptoms are usually associated with widespread but variable airflow obstruction and an increase in airway response to a variety of stimuli.
- 4. The events of asthma are: Airway obstruction(reversible) Hyper-responsiveness.
- 5. Difficult breathing Wheezing Chest tightness Coughing
- 6. Examples of triggers are: Allergens: Pollens, moulds, house dust mite, animals (dander, saliva and urine) Industrial chemicals: paints, hair sprays, penicillin's Drugs : Aspirin, ibuprofen and other prostaglandin synthetase inhibitors(aspirin, ibuprofen, NSAIDs),β-adrenoceptor blockers(Atenolol)
- 7. Foods: A rare cause but examples include nuts, fish, seafood, dairy products, food colors, especially tartrazine, benzoic acid and sodium metabisulfite Environmental pollutants: Traffic fumes. cigarette smoke Other industrial triggers: Wood or grain dust, cotton, dust, grain weevils and mites Miscellaneous: Cold air, exercise, hyperventilation, viral respiratory tract infections, emotion or stress,
- 8. The two main causes of asthma symptoms are: 1. Airway hyper-responsiveness: It is an increased tendency of the airway to react to stimuli or triggers to cause an asthma attack. 2. Bronchoconstriction: It is a narrowing of the airways that causes airflow obstruction.
- 9. Types of asthma: Asthma can be classified according to the underlying pattern of airway inflammation with the presence or absence of eosinophils in the airways. It includes Extrinsic asthma when an allergen is thought to be the cause of their asthma. More common in children where triggers, such as dust mite, cause IgE production. Intrinsic asthma develops in adulthood, with symptoms triggered by non- allergenic factors such as a viral infection, irritants which cause epithelial damage and mucosal inflammation, emotional upset which mediates excess parasympathetic input or exercise which causes water and heat loss from the airways, triggering mediator release from mast cells.
- 11. Immediate reaction includes Mast cell components are released as a result of an IgE antibody-mediated reaction on the surface of mast cell. Histamine and other mediators of inflammation are released from mast cells for example Leukotriene's (C4, D4, E4) Bronchoconstriction and also causes mucus gland to hyperactive and start producing mucous Prostaglandins, Vasodilation and causes more fluid to come out and cause wall to swell up Bradykinnins Adenosine as well as Various chemotactic agents that attract eosinophils and neutrophils.
- 12. Macrophages release prostaglandins, thromboxane and platelet-activating factor(PAF). PAF sustain bronchial hyperactivity and causes capillaries to leak plasma that leads to mucosal edema PAF also facilitates the accumulation of eosinophil's within airways
- 13. Eosinophils release various inflammatory mediators such as leukotriene C4, and PAF, which results in epithelial damage and thick mucus production that causes further deterioration in lung function. Hypertrophy and hyperplasia of bronchial smooth muscle occur by these cell-derived mediators. Mucus gland hypertrophy leading to excessive mucus production and airway plugging, airway oedema, acute bronchoconstriction and impaired mucocilliary clearance.
- 14. Pathophysiology
- 16. Asthma can present in a number of ways. It may be manifest as a persistent cough but commonly described as Recurrent episodes of difficulty in breathing (dyspnea) associated with wheezing(a high-pitched noise due to turbulent airflow through a narrowed airway.)
- 17. A series of routine tests has been developed to assess asthma such as 1. Forced expiratory volume(FEV) This a most useful test for abnormalities in airway function. This is measured by means of lung function assessment apparatus such as a spirometer. The patient inhales as deeply as possible and then exhales forcefully and completely into a mouthpiece connected to a spirometer. The FEV1 is a measure of the FEV in the first second of exhalation.
- 18. I. Forced vital capacity(FVC) can also be measured, which is an assessment of the maximum volume of air exhaled with maximum effort after maximum inspiration. II. FEV1 is usually expressed as a percentage of the total volume of air exhaled, reported as the FEV1/FVC ratio. III. Tidal volume is the volume of air inspired or expired during normal breathing. IV. Residual volume (RV) is the volume of air left in lungs after maximum expiration. V. Total lung capacity = VC + RV Normal individual can exhale at least 70% of their lung capacity in 1 sec.
- 19. I. Peak flow meter is a useful means of self-assessment for the patient. it measures peak expiratory flow( PEF) rate. II. Peak expiratory flow rate ,the maximum flow rate that can be forced during expiration. It can be used to assess the improvement or deterioration in the disease as well as the effectiveness of treatment. A healthy average young adult male typically has a PER of 550 to 700L/minute
- 20. These lung function test are used to demonstrate the presence of air flow obstruction. Other test include • Skin pricking test for IgE testing for specific allergens • X-Rays • Eosinophilic airway inflammation can be determined by using sputum differential count Chest X-Rays
- 21. The aim of asthma management is to have complete control and have no exacerbations of disease BTS defines asthma control as • No daytime symptoms • No night time wakening • No requirement of rescue medicines • No asthma attack • No limitation on activity • Normal lung function tests FEV1 >80% • Minimal adverse effect from medications
- 22. Persistent asthma Components of severity Intermittent Mild Moderate Severe Impairments Symptoms ≤2 days/weeks >2 days/week but not daily Daily Throughout the day Nighttime awakenings ≤2x/weeks 3-4x/month >1x/week but not nightly Often 7x/week SABA use for symptom control ≤2 days/weeks >2 days/week but not daily Daily Several times per day
- 23. Persistent asthma Components of severity Intermittent Mild Moderate Severe Interference with normal activity None Minor limitation Some limitation Extremely limited Normal FEV1/FVC 8-19yrs, 85% 20-39yrs, 80% 40-59yrs, 75% 60-80yrs, 70% Lung function • Normal FEV1 between exacerbatio n • FEV1 >80% predicte d • FEV1/FV C normal • FEV1 ≥80% predicte d • FEV1/FV C normal • FEV1 >60% predicted • FEV1/FVC reduced 5% • FEV1 <60% predicted • FEV1/FVC reduced >5%
- 24. Persistent asthma Component of severity Intermittent Mild Moderate Sever Risk Exacerbations requiring oral systemic corticosteroids 0-1 year ≥2 in 1 year Consider severity and interval since last exacerbation. Severity and frequency may fluctuate over time for patients. Relative annual risk of exacerbations may be related to FEV1.
- 25. Persistent asthma Intermittent Mild Moderate Sever Level of treatment required to maintain control Step-1 Step-2 Step 3 or 4 Step 5 or 6
- 26. Reliever medications Inhaled Short acting beta adrenoceptor agonist (Salbutamol 200µcg) Inhaled anti-cholinergic agent (Ipratropium slower onset of action) Long acting beta adrenoceptor agonist Oral bronchodilators (Theophylline)
- 27. Preventive medication Anti-inflammatory agent (Corticosteroids ; Beclomethasone or Budesonide 400µcg/day) Leukotriene receptor antagonist (Montelukast, Zafirlukast) IgE monoclonal antibodies (Omalizumab) Oral corticosteroid
- 28. Step2: Regular preventer therapy Step1: Mild intermittent asthma Inhaled short acting beta 2 agonists as required Add inhaled steroid 200-800µcg/day 400µcg is an appropriate starting dose for many patients Start a dose of inhaled steroid appropriate to severity of disease
- 29. Step 5: Continues or frequent use of oral steroids • Use daily steroid tablet in lowest dose providing adequate control • Maintain high dose inhaled steroids at 2000 µcg/day • Consider other treatment to minimize the use of steroid tablet • Refer patient for specialist care. Step 4: Persistent poor control • Consider trials of increasing inhaled steroids upto 2000 µcg/day • Addition of fourth drug leukotriene receptor antagonist, SR theophylline Step 3: Add on therapy Add inhaled beta 2 agonists (LABA) Assess control of asthma • Good response to LABA • Benefit from LABA but control still inadequate-continue LABA and increase inhaled steroid dose to 800µcg/day • No response to LABA- stop LABA and increase inhaled steroid to 800µcg/day. If control still inadequate institute trial of other therapy e.g. leukotriene receptor antagonists or SR theophylline
- 34. Drugs ADRs Beta 2 agonists High doses: hypokalemia, aggravation of angina Inhaled corticosteroids Oral candidiasis, adrenal suppression Oral corticosteroids Mineralocorticoid effects include: potassium loss, muscles weakness, hypertension, sodium and water retention. Ipratropium Dry mouth Nedocromil sodium Nausea, coughing, throat irritation, headache Theophylline Hyperglycemia, hypotension, cardiac arrhythmia Leukotriene receptor antagonist Abdominal pain, upper respiratory tract infections
- 35. The choice of suitable inhalation devices is vital in asthma. Incorrect use of inhalers will lead to sub-optimal treatment.
- 36. Metered dose aerosol inhaler Dry powder inhalers Nebulisers (nebuliser produces an aerosol by blowing air or oxygen through a solution to produce droplet of 5µm or less in size)
- 37. It usually contains a solution or suspension of active drug, with typical particle size of 2-5µm in a liquefied propellant. Operation of device releases a metered dose of drug with droplet size of 35-45µm. This increase in droplet size is due to propellant which evaporates when expelled from inhaler
- 38. MDIs have the advantage of being multidose, small and widely available for most drugs used in asthma. Corticosteroids administered by MDIs causes oral candidiasis so the patient is advised to gargle with water after using inhalation and to expel the water from mouth afterwards
- 42. Corticosteroids and long-acting beta agonists Some inhaled asthma medication combinations contain both a corticosteroid and a bronchodilator: • Fluticasone and Salmeterol (Advair Diskus) • Budesonide and Formoterol (Symbicort) • Mometasone and Formoterol (Dulera) • Fluticasone and Vilanterol (Breo) • Formeterol and Beclomethasone (Foster)
- 43. Long-acting beta agonists (LABAs) The most commonly used LABA for asthma is salmeterol (Serevent). Quick relief drugs Albuterol (ProAir HFA, Ventolin HFA, others) Levalbuterol (Xopenex HFA)
- 44. Clinical pharmacy and therapeutics Rogger Walker 5th edition Applied therapeutics 9th edition (Marry Anne Koda-Kimble)