1. ASTHMA Dr. Saviour K. Assoah (Medicine Dept)

2. OUTLINE Definition Epidemiology Risks / precipitating factors Symptoms and signs Pathophysiology Types of asthma Investigations Management

3. Definition Is a chronic inflammatory disease of the airway which is characterised by recurrent episodes of dyspnoea, cough, and wheeze caused by reversible airway obstruction. Three factors that contributes to the narrowing of the airway (bronchial muscle contraction, mucosal swelling or inflammation and increase mucus production

4. Epidemiology WHO estimates 300 million people world wide suffering from asthma with approximately 250,000 asthma related annual death GINA estimates global prevalence of asthma ranging from 1 to 18% of total population of different countries WHO estimates incidence in Ghana as 1.5/1000 per year

5. Risks/ precipitating factors Genetic predisposition (family history, certain genes) Allergens: pollen, fungal spors, fur, dust mite Viral infections: URTI Pharmacological agents: beta blockers, ACE inhibitors Exercise Physical factors: cold weather

6. Air pollutants: irritant gases, sprays, Stress Hormonal factors ; fall in progesterone

7. Symptoms Cough (often nocturnal) Wheezing Chest tightness Shortness of breath

8. Signs Tachypnoea Audible wheeze Hyperinflated chest Hyper-resonant percussion note Diminished air entry

9. Severe Inability to complete sentences Pulse >110bpm Respiratory rate >25cpm PEF 33-50% of predicted

10. Life threathening Silent chest Cyanosis Bradycardia Exhaustion PEF <33% of predicted Confusion

11. Pathophysiology Early phase : mast cell releases (histamine, prostaglandin D2, leukotriens) leading to muscle contraction, increase microvascular leakage/ permeability, increase mucus secretion) these acts as chemoattractant for inflammatory cells Late phase:inflammation with recruitment of eosinophils, T lymphocytes, neutrophils

12. Types of asthma Atopic asthma: classical IgE mediated, allergen sensitization, seen from childhood, has positive family history of asthma Non atopic asthma: non allergen sensitization, no family history, patients are adults Drug induce asthma : sensitive to certain drugs Occupation asthma: stimulants such as fumes, chemical dust Exercise induced asthma: begins after exercise and stop after 30mins, worsen on cold and dry climate

13. investigations FBC, CRP, Blood culture ABG analysis Chest x ray Spirometry

14. Management Asthma education Avoidance of precipitating factors Mild intermittent asthma; symptoms less than once a week for 3 months( beta agonist bronchodilator eg: salbutamol or terbutaline Exacerbation of asthma (uses inhaler 3times a week) introduce regular preventive therapy thus inhaled corticosteroids eg beclometasone, fluticasone Add on therapy: long acting beta agonist eg: salmeterol, formoterol

15. Severe asthma Sit patient up (prop up) and give high dose oxygen in 100%, via non –rebreathing bag Administer salbutamol 5mg (or terbutaline 10mg) plus ipratropium bromide 0.5mg nebulized with oxygen Hydrocortisone 100mg iv or prednisolone 40- 50mg po or both if very ill

16. Life threatening asthma Inform the ICU and senior colleague Add magnesium sulphate 1.2-2g iv over 20min Give salbutamol nebulizers every 15min, or 10mg continuously per hour Monitor ECG, watch for arrhymias

17. Further management if improving 40-60%oxygen Prednisolone 40-50mg/24h po continue for at least 5days Nebulized salbutamol every 4h Monitor peak flow and oxygen saturation

18. If patient not improving after 15- 30min Continue 100% oxygen and steroids Hydrocortisone 100mg iv or prednisolone 30mg po if not already given Give salbutamol nebulizers every 15min, or 10mg continuously per hour Continue ipratropium 0.5mg every 4-6h

19. References Oxford handbook for clinical medicine https://ginasthma.org/wp-content/ Davidson’s principles and practice of clinical medicine https://www.mja.com.au/ (Medical Journal of Australia)