Chronic Obstructive Pulmonary Disease

1. Chronic Obstructive Pulmonary Disease Philip Kiely pcdk1e08@soton.ac.uk

2. Outline • Go through COPD using DAPSICAMP • Focus on understanding pathophysiology and clinical features • Obstructive vs. Restrictive Lung Disease • Respiratory Failure

3. DAPSICAMP Definition Aetiology Pathophysiology Signs and symptoms Investigations Complications Alternative diagnoses Management Prognosis

4. Definition: COPD is an umbrella term for a spectrum of diseases that result in non-reversible airflow limitation • Typically a combination of chronic bronchitis and emphysema • Chronic bronchitis = a productive cough on most days for 3 months in 2 consecutive years • Emphysema = destruction of airspaces distal to the terminal bronchiole

6. Facts and stats • COPD represents long-term damage caused by inhaled irritants • Cigarette smoking is the predominant risk factor • Prevalence of 1.5 million; mortality 23,000 per year in the UK • By 2020, it is predicted to become the third leading cause of death worldwide • Currently causes 1 in 8 hospital admissions

7. Pathophysiology • Damage to the airways results in mucus gland hypertrophy and goblet cell hyperplasia • Inflammation which over time progresses to fibrosis and scarring • Air becomes trapped in the lungs due to mucus plugging of small airways and loss of connective tissue

8. Signs and symptoms • Tachypnoea (RR > 20) • Use of accessory muscles of respiration • Hyperinflation ( AP diameter, loss of cardiac/liver dullness) • Reduced cricoternal distance • Reduced chest expansion • Cyanosis • Wheeze • Prolonged expiration • Pursed lip breathing

9. Investigations • Bedside - Spirometry - (FVC < 80% predicted, FEV1:FVC < 70%) • Bloods - normocytic normchromic anaemia (low Hb, normal MCV), raised PCV (> 45%) • Imaging - CXR - hyperinflation, spherical heart, decreased peripheral vascular markings

12. Complications • Main complications are respiratory failure and cor pulmonale • Respiratory failure (PaO2 < 8 kPa, PaCO2 > 7 kPa) • Cor pulmonale = fluid overload secondary to respiratory disease • Features include raised JVP, ascites and peripheral oedema

13. Alternative Diagnosis

14. Management • In treating any condition it is important to understand what you as the clinician are trying to achieve • In COPD, the goals of management are to limit the severity and frequency of acute exacerbations and to limit overall disability = lifestyle advice + pharmacotherapy

16. Prognosis

17. Obstructive vs. Restrictive Lung Disease • Obstructive = inability to get air out • Restrictive = inability to get air in • Obstructive lung disease: COPD, Asthma, Bronchiectasis, CF PEFR, FVC, FEV1: FVC • Restrictive Lung Disease: Fibrosis (2º to radiation, medication, asbestos exposure) FEV1, FVC, but normal FEV1: FVC ratio

18. Respiratory Failure • The term organ failure represents that systems inability to perform its primary function • With the lungs this is oxygenation of the blood and elimination of carbon dioxide • In hypoxaemic respiratory failure (Type I) PaO2 is < 8 kPa, but CO2 is low to normal. This is caused by V/Q mismatching • In hypercapnic respiratory failure (Type II) PaCO2 is > 6.5 kPa, hypoxaemia is also common