Transcript ASTHMA
ASTHMA Definition • Reversible airflow obstruction + • Airway hyper-reactivity Pathology • Inflammation involving eosinophils and T lymphocytes • Release of various mediators and cytokines • Initially reversible, spontaneously or with drugs • Eventually permanent structural change results in irreversibility = remodelling Remodelling • Extent varies between patients • Lung function decline faster than in non asthmatics • Early intervention may prevent decline Incidence • 20% of children have asthma • 6% of adults • 15% cases are late onset • Boys . Girls Statistics • 5 million people in uk receive asthma treatment • NHS treatment costs £850 million/year • 18 million working days lost/year Presentation • Symptoms • Cough • Expiratory wheeze • Chest tightness • Dyspnoea • Nocturnal cough • Exercise induced wheeze Diagnosis • Twice daily PEF recording for 2 weeks • 15% variation = asthma • Therapeutic trial of salbutamol • >15% improvement in PEF after 15-30 mins = asthma • 2 week trial inhaled or oral steroid • 15% improvement in PEF = asthma Differential diagnosis • Adults • • • • • • • Gastro oesophageal reflux Bronchiectasis COPD LVF PE Interstial lung disease Tumour Differential diagnosis • Children • Cystic fibrosis • Ciliary dyskinesia • Foreign body inhalation • Gastro oesophageal reflux • Bronchiectasis Diagnosis - Children • Can’t do PEFR • Daignosis made on history and response to treatment • 30% children wheeze in first 3 years of life Differential diagnosis • COPD Spirometry fev1/fvc < 75% • LVF Older, echo lvedp <50% • PE • Vocal cord dysfunction • Psychogenic breathlessness Triggers • Infections particularly viral • Allergens e.g. house dust mite, pollens, animals. • Occupations e.g. isocyanate containing paints, flour • Environmental pollutants e.g. cigarette smoke, sulphur dioxide Triggers • Drugs e.g. beta blockers • Exercise • Cold air • Hyperventilation • Foods • Psychological factors Management • Aims • Control of symptoms and exacerabtions • Minimal lifestyle disturbance • 40% of asthmatics say their symptoms affect their lifestyle Management • BTS guidelines • Stepwise approach Step one • Mild intermittent asthma • Short acting inhaled beta agoinst as required Step two • Needing beta agonist every day • Regular preventer therapy • Add inhaled steroid 200800micrograms/day • Start at dose appropriate to severity of disease • 400 micrograms for most people Step 3 add on therapy • Add inhaled long acting beta agonist = LABA • i.e. salmeterol • oxis Poor response • Stop LABA • Increase inhaled steroid to 800mcg/day If still symptomatic • Consider slow release theophyline • Or • Leukotriene receptor antagonist Step 4 • Increase inhaled steroids • Adults 2000mcg/day • Children 800mcg/day • Add in 4 th drug • LTRA • SRT • Oral beta agonist Step 5 • Oral steroids in lowest possible dose • Maintain high dose inhaled steroids • Refer to respiratory specialist Short acting beta 2 agonists • Relievers • Salbutamol and terbutaline • Use on prn basis • Useful before exercise Short acting beta 2 agonists • Overuse • Tachycardia • Tremor • hypokalaemia Inhaled corticosteroids • Preventers • Improves symptoms and lung function • Might prevent permanent airway damage Inhaled corticosteroids • Beclomethasone, fluticasone and equally effective • Fluticasone twice as potent needs half the dose • Thrush and dysphonia decreased by rinsing mouth out after use abd using a spacer Inhaled corticosteroids • High doses associated with • Cataract formation • Adrenal suppression • Slow growth rate in children – no evidence that final height is affected Adrenal suppression • Presentation • • • • • • Fatigue Weigth loss Anorexia nausea Abdo pain Hypoglycaemia seizures LABA • Salmeterol and eformeterol • Patients > 5 years • Relieves symptoms and improves lung function • Adding ALBA to inhaled steroids is more effective than doubling the dose of steroid LTRA • Montelukast and zafirlukast • Block action of leukotrienes • Montelukast – add on therapy age 2 years and older • Zafirlukast – monotherapy or add on therapy age 12 years and older LTRA • Reduce exacerbations • 5-8% improvement lung function less than inhaled steroids or LABA • 4 week trial continue if symptoms and lung function improve LTRA • Side effects • GIT upset • Headache • Rash • Churg strauss syndrome Theophylline • Phyllocontin continuus • Has anti inflammatory actions • Use at step 3 • Side effects • GIT • Arrythmias • Hypokalaemia • convulsions Oral steroids • Should be under specilaist review • Monitor • BP • Blood sugar • Osteoporosis prevention Delivery systems • • • • MDI 10% dose reaches lungs MDI + spacer Breath actuated inhaler Dry powder inhaler • Turbohaler • Accuhaler • Clickhaler Children • 0-2 yrs mdi + spacer mask • 2-5 yrs mdi + spacer • > 5 yrs mdi + spacer, breath actuated inhaler or dry powder inhaler Lifestyle measures • Avoid precipitating factors • Housedust mite • Vacuuming • Impermable matress covers • Reduced soft furnishings Lifestyle measures • No smoking infamily • Keep pets out of bedrooms • Keep weight down Acute asthma • Signs of severity • Children • Inability to feed • Use of accessory muscles • Sub costal recession • Nasal flaring Acute asthma • Signs of severity • Adults • Pulse > 110 bpm • Resp rate > 25/min • PEF 33-50% max • Inability to complete sentenes Life threatening • Cyanosis • Silent chest • Bradycardia • Hypotension • Poor resp effort • PEF < 33% max Management • Oxygen • Nebulised beta 2 agonist • Salbutamol 5mg • Atrovent 500mcg • Halve doses for children Management • Short course oral steroids • Adults 40mg/day • Children > 5 30mg/day 3 days • Children 2-5 20mg/day 3 days • Children < 2 10mg/day 3 days