1 / 32

Asthma

Asthma . By Alice Keyte ajk1g10@soton.ac.uk. DAPSICAMP. Definition Aetiology Pathophysiology Signs and Symptoms Investigations Complications Alternative Dx Management Prognosis. Definition. WHAT IS ASTHMA?

avent
Download Presentation

Asthma

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Asthma By Alice Keyte ajk1g10@soton.ac.uk

  2. DAPSICAMP Definition Aetiology Pathophysiology Signs and Symptoms Investigations Complications Alternative Dx Management Prognosis

  3. Definition • WHAT IS ASTHMA? • Chronic Inflammatory airway disease of the large airway, characterised by variable, reversible, widespread airway obstruction and hyper-responsiveness. • GINA – Global Initiative for Asthma • http://www.ginasthma.org/

  4. Chronic Vs Acute Severe

  5. Chronic Asthma • Periodic/episodic asthmatic symptoms: • Cough • Chest tightness • Wheezing • Seasonal (allergy to pollens) and Diurnal variation

  6. Aetiology of Atopic Asthma Polygenic inheritance (genes encoding cytokines, T-cell receptor, IgE receptor, MHC). MZ twin concordance 20-60% and first degree relatives with asthma increases risk by 10x Atopyalso has a genetic basis.

  7. Aetiology Immune system is Th2 primed during fetal life and early childhood which promotes allergic sensitisation. Higher antigen dose and repeated exposure promotes Th2 responses. Histamine gives allergic symptoms. IgE becomes important as patient develops asthma. Repeated exposure causes immune cells to reside in tissues and become hypersensitive. Viral infections in early life facilitates sensitisation by damaging the epithelial surface.

  8. Triggers • Cold air • Exercise • Allergens (pets, house dust mite, pollens) • Non-specific irritants (cigarette smoke)

  9. Pathophysiology • Factors contributing to obstruction: • smooth muscle constriction (leukotriene mediated) • oedema due to increased vascular permeability (leukotriene mediated) • mucus hyper-secretion (leukotriene mediated) • dead epithelial cells sloughed off by eosinophil toxins • Tissue infiltration with immune cells (due to chemoattractant release)

  10. Damage to epithelial barrier means asthmatics are more likely to get LRTI following URTIs. Permanent remodelling occurs, giving smooth muscle hyperplasia, hypertrophy, thickening of BM.

  11. Pathophysiology summary

  12. Signs and Symptoms CLINICALLY: Cough Chest tightness Wheezing Dyspnoea (short of breath)

  13. How Well Controlled Are You? • 3 Questions by Royal College of Physicians: • Have you had difficulty sleeping because of your asthma? • Have you had your usual asthma symptoms during the day time? • Has your asthma interfered with your usual activities?

  14. Examination • Frequently normal in chronic asthma • Hyperinflation – if had asthma for many years • Wheezes: • Expiratory • Diffuse (all over the chest) • Polyphonic (musical) • Signs of atopy (associated signs of asthma): • Eczema • Conjunctivitis • Allergic rhinitis

  15. Diagnosis • Not always easy • Important to exclude: • Inhaled foreign bodies, CF in children • Carcinoma, pulmonary oedma (HF) in adults

  16. Alternative Dx • Atypical Symptoms: • Cough without wheeze • Voice disturbance • Lack of airways obstruction on spirometry • No variation (suggests COPD or HF) • No relief with B2 agonist • PMH: • Cardiac disease (MI, hypertensive) • Smoking history • Exam: • Any signs other than wheeze (crackles, bronchial breathing) • Tar staining • Features associated with cardiac disease (peripheral oedema)

  17. Alternative Dx • CONDITIONS: • COPD • Heart Failure • Bronchiectasis • GORD • Pulmonary fibrosis • Large airway obstruction (rare) • Obliterative bronchiolitis

  18. Main Tests • SPIROMETRY • PEFR (Peak Expiratory Flow Rate) • PEFR variability (>20%) – someone who’s uncontrolled • Bronchodilator responsiveness • Steroid responsiveness • Methacholine or histamine challenge (give and see bronchoconstriction)

  19. Management • 3 goals of treatment: • Control of asthma symptoms • Prevent exacerbations (single cause of morbidity and mortality) • Preservation of normal lung function (reduce airway remodelling as = decline in lung function)

  20. British Thoracic Guidelines

  21. Acute Severe Asthma • O SHIT – first thing you do. • MOVE – do for anyone acutely unwell • M – monitor (3 lead cardiac monitoring, BP, pulse oximetry) • O – oxygen • V – venous access (drugs, fluids) • E – ECG

  22. Assess Severity - history • Will be difficult to get a history so make it CONCISE! • Determine if AT RISK OF GOING TO ITU • Risk factors: • Previous ITU stay • Previous mechanical ventilation for asthma • Previous hospital admission for asthma (recent) • Exclude anaphylaxis

  23. Assess Severity - Examination RED = pre-terminal signs to be aware of! GCS HR BRADYCARDIA BP RR Cyanosis Exhaustion Chest expansion (air in and out) SILENT CHEST Pneumothorax (complication of asthma) EXCLUDE ANAPHYLAXIS

  24. Assess Severity - Investigations SpO2% (<92%) PEFR - may be too unwell, try and find out their best – now as a % of their best (<33% predicted) ABG – if signs of hypoxemia + sats <92 (PaO2 <8kPa) CXR if indicated (pneumothorax, pneumonia) Beta blockers should not be prescribed to asthmatics

  25. BTS Guidelines http://www.brit-thoracic.org.uk/document-library/clinical-information/asthma/btssign-guideline-on-the-management-of-asthma/ MODERATE ACUTE SEVERE LIFE THREATENING

  26. Treatment • O SHIT! (sit them up) 1. O – Oxygen 2. S – Salbutamol (nebulised, often, back to back) 4. H – Hydrocortisone (if can take oral – prednisolone 30/40mg depending on size) 3. I – Ipratropium Bromide (inhibit parasympathetic NS = increase intracellular cyclic AMP = broncodilation. Nebulised back to back with salbutamol ) 5. T – Theophylline / Magnesium sulphate (take senior advice!) • MONITOR frequently (1/2 hr – 1hr obs) • Things can change rapidly

  27. Prognosis • The prevalence of asthma is rising. Possible reasons for this are: • Increased detection • Improved living standards and fewer childhood infections (hygiene hypothesis) • Change in indoor environment (central heating increases dust mite exposure)

  28. Education Important Exams! Compliance issues with inhaled therapies

  29. OSCE’s • Inhaler + Spacer Technique • Peak Flow Technique • Look in the green unofficial guide to passing OSCEs for step to step guides.

  30. Questions 1. Outline treatment strategies for an acute exacerbation of asthma Nebulised – Salbutamol, Ipratropium Bromide IV – Steroids, Methyl Xanthines, MgSO4

More Related