Obstructive Airway Disease

1. Obstructive Airway Disease Asthma & COPD Rachel Ventre FY1

2. Spirometry/ PFT • Obstructive –  FEV1/FVC ratio • Asthma • COPD • Bronchiectasis • CF • Restrictive – FVC & FEV1. Normal or  ratio. • Kyphosis/Scoliosis • ILD • Connective tissue diseases • Infection - pneumonia

3. Asthma

4. Definitions • Asthma • Common, chronic inflammatory airway disease, characterised by variable (diurnal) reversible airflow obstruction, airway hyper-responsiveness, bronchial inflammation and bronchospasm.

5. Aetiology • Environment • maternal smoking during pregnancy • low air quality (pollution) • sterile environment (Hygiene hypothesis) • occupational allergens (isocyanates, epoxy resins) • Genetic • FHx of atopy. +ve twin studies.

6. Asthma Triggers?

7. Pathophysiology 3 main features: • Airway narrowing – bronchiole constriction • Irritation – inflammation of mucosal lining • Blockage – excess mucous production forming plugs

8. Epidemiology • Increasing prevalence in UK • FHx of atopy • B>G3:2 in children but equal in adults • Onset – any age • Atopy? • Type I hypersensitivity to allergens • Increased tendency for T lymphocyte’s to drive IgE production on allergen exposure • Associated with Asthma, Eczema and Allergic Rhinitis (Hayfever). Runs in families.

9. Presentation

10. Investigations Initial Dx & assessseverity Bedside: • PEFR – with diary showing diurnal variation (>20%), morning dip • Pulse oximetry Blood: • ABG – acidotic? • Eosinophil levels, Aspergillus antibody • FBC (WCC), CRP, U&E • Blood and sputum cultures Radiology: • CXR – hyperinflation, pneumothorax, pneumonia? Special tests: • Pulmonary function tests • FEV1/FVC < 80% • Spirometry – Flow volume loop showing obstructive picture • 15% improvement post – salbutamol • Skin prick tests – allergen identification BTS uses a ‘response to therapy’ approach to asthma Dx. Chronic monitoring: PEFR – best comparison

11. Management Conservative: • Smoking cessation • Check inhaler technique • Patient education – avoid allergens/precipitants • Emergency plan – acute exacerbations • Vaccinations – pneumococcal and influenza • Medical: BTS guidelines • Start at appropriate level for severity. Move up if necessary and step down if good control for 3 months. Rescue steroids if required in exacerbations.

12. Stepwise Rx

13. Acute Asthma • Acute exacerbations are common • Medical emergency • Responsible for 1000-2000 deaths/yr ? ?

14. Management Resuscitate  ABCDE • Monitor O2 sats, ABG and PEFR • High flow 100% Oxygen (15L via non-rebreathable mask) aim sats 94-98% • Nebulisers • SABA (Salbutamol 5mg continuously then 2-4hourly) + Ipatropium Bromide 0.5mg QDS • Systemic corticosteroids • hydrocortisone 100-200mg IV then Prednisalone 40mg PO for 5/7 • Magnesium sulphate 2g over 20mins IV • Bronchodilators IV (ITU only, need cardiac monitoring) • Aminophylline or Salbutamol • Assess severity (ventilation) • Consider ITU or intubation if worsening hypoxia and PEFR despite Rx • Hypercapnia, resp acidosis, coma, respdrepression/arrest. Also if patient is tiring! • Consider patient performance status (poor  poor ITU prognosis) • Rx underlying cause – infection (ABx) or pneumothorax.

15. COPDChronic obstructive pulmonary disease

16. Definitions • COPD • Chronic progressive lung disorder, characterised by (mostly) irreversible airflow obstruction, FEV1 <80% predicted and FEV1/FVC ratio <70%. • Chronic bronchitis = clinical • Cough & sputum, most days, 3/12 over 2years • Chronic inflam of bronchi (medium) • Emphysema = histopathological, CXR/CT changes • Permanent destructive enlargement of airspaces • Distal to terminal bronchioles (alveolar) = bullae

17. Aetiology • Bronchial and alveolar damage caused by environmental toxins • Cigarette smoking • Process not fully understood. Processes causing lung damage include: • Genetic • Alpha 1 antitrypsin deficiency (<1%)  Emphysema

18. Epidemiology • Very common, many undiagnosed • More common in lower socioeconomic status (relates to smoking prevalence) • Presents in middle age or later • M>F due to smoking tendencies in past

19. Presentation • Symptoms • Chronic productive cough • Following colds and in winter months • Increase severity and frequency over time • Sputum – can be blood stained in advanced disease • Recurrent respiratory infections • Exertional dyspnoea & reduced exercise tolerance • Regular morning cough • Wheeze

20. Presentation • Signs:

21. Investigations • Bedside: • PEFR – reduced • Blood: • Secondary polycythaemia • ABG - Hypoxia, normal or raised CO2 • Radiology: • CXR • Chest CT – bullae and lung volumes • Special tests: • Pulmonary function tests • Spirometry – reduced FEV1 <80% • FEV1/FVC ratio – reduced <70% (see below) • Increased lung volumes • CO gas transfer coefficient decreased when significant alveolar destruction • ECG/Echo – corpulmonale? • Sputum/blood culture

22. CXR • Hypertranslucent lung fields • Low flat diaphragm • Bullae • Hyperinflation • >6ribs ant •  peripheral lung markings • Elongated cardiac shadow

23. Diagnosis/Severity 4 classifications of severity of COPD:

24. Management • Conservative: • Avoid bronchial irritation • Smoking cessation  limits FEV1 decline • Occupational allergens • Exercise • Pulmonary rehabilitation • Weight loss – correct obesity, nutritional improvement • Rx depression/social isolation – often associated

25. Management - medical

26. Management • Surgery: • Lung transplant in lung patients with alpha 1 antitrypsin deficiency • Bullaectomy • lung volume reduction surgery (Lobectomy – now close off the lobe using a filter)

27. Acute COPD Mx • Rescusitation – ABCDE • 24% O2, 2L via nasal cannula or non-variable flow venture mask. • If Type II resp failure target 88-92% • Nebulisers - bronchodilators • Corticosteroids (oral/IV) • Fluids • Theophylline IV • Empirical ABx IV if infection (+/- pseudomonalcover? Tazocin, Meropenum, Gentamycin) • Consider ventilation • Consider NIV, intubation or ITU in severe cases. • Indication for NIV  persistent hypercapnia type II RF, deterioration despite 1hr best medical Rx and patient tiring.

28. Video by Asthma UK PEFR • http://www.youtube.com/watch?v=DxBDfqPmaZU

29. Video Asthma UKInhaler technique • MDI • http://www.youtube.com/watch?v=FqztOZLqFhE • All other inhalers • http://www.asthma.org.uk/knowledge-bank-treatment-and-medicines-using-your-inhalers

30. LTOT • Indications: • Chronic hypoxaemia e.g COPD, ILD, Lung Ca • PaO2 <7.3kPa on air when clinically stable • PaO2 7.3-8kPa if 2* polycythaemia or pulmonary hypertension (clinical/echo) • Nocturnal hypoventilation • e.g obesity, OSA, chest wall disease • Specialist referral. Usually with CPAP or NIV. • Palliative care • For Rx of dyspnoea in terminal illness. • Assessed by respiratory physiologists • requires ABG on and off O2.

31. Any Questions

32. References • BTS guidelines asthma - http://www.brit-thoracic.org.uk/Portals/0/Guidelines/AsthmaGuidelines/qrg101%202011.pdf • BTS guideline COPD - http://www.nice.org.uk/nicemedia/live/13029/49399/49399.pdf • BTS guidlein LTOT - http://www.brit-thoracic.org.uk/Portals/0/Clinical%20Information/Home%20Oxygen%20Service/clinical%20adultoxygenjan06.pdf • Spirometry guideline - http://www.brit-thoracic.org.uk/Portals/0/Clinical%20Information/COPD/COPD%20Consortium/spirometry_in_practice051.pdf • Asthma UK • Patient.co.uk – professional • Acutemed.co.uk • http://www.eguidelines.co.uk/eguidelinesmain/gip/vol_13/aug_10/jones_copd_aug10.php#.UlqCeBDZIa8 • Good books for finals: Clinical cases uncovered