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Chronic Obstructive Pulmonary Disease (COPD)

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How to diagnose and manage COPD for doctors, medical student exams, finals, OSCEs and MRCP PACES

Definition of COPD

  • Airflow obstruction that is:
    • Not fully reversible
    • Progressive
    • Does not change markedly over several months
  • Combination of airway and parenchymal damage
    • This occurs as a result of chronic inflammation and encompasses chronic bronchitis and emphysema
    • An exacerbations of COPD is a rapid and sustained worsening of symptoms beyond normal day-to-day variations

 

Epidemiology of COPD

  • Prevalence: an estimated 3 million people have COPD in the UK
  • Incidence: approximately 1% overall  and 10% in over 75 year olds

 

Causes or risk factors for COPD

  • Smoking
    • In UK, 90% of COPD is caused by long-term smoking
    • smokers of >30/day have a 20x risk compared to non-smokers, although only 10-20% of heavy smokers get COPD
  • Air pollution
  • Biomass fuels
  • Alpha-1-antitrypsin deficiency
    • Serum protease inhibitor
    • Can present with lung disease (75%) or liver cirrhosis (25%)
      • Pan-acinar (lower lobes) as opposed to centri-lobular in smoking and environmental exposures

 

Causes of acute exacerbations of COPD

  • Viral
    • Rhinovirus, influenza, coronvirus, adenovirus, RSV
  • Bacteria
    • Common
      • Strep. Pneumonia
      • Haemophilus
      • Moraxella
        • WCC may be normal with mild symptoms
    • Rare
      • Staph aureus (during flu season)
      • Pseudomonas

 

Presentations of COPD

  • Exertional breathlessness
  • Chronic cough
  • Sputum production
  • Wheeze
  • Frequent winter bronchitis
  • Fatigue
  • Ankle Swelling
  • Weight loss

 

 

Differential diagnosis of COPD

  • Asthma
  • Bronchiectasis
  • Lung cancer
  • In acute exacerbations:
    • Pneumothorax
    • Pneumonia
    • Pulmonary oedema
    • Large pleural effusion
    • PE

 

Investigation of COPD

  • Bedside
    • Pulse oximetry
    • Sputum MCS
    • ECG
      • May show tall P-waves of cor pulmonare, RBBB and RVH (right axis deviation, prominent V1 R-wave and V6 S-wave)
    • Calculate BMI
  • Bloods
    • FBC: Hb and Hct can be raised in response to chronic hypoxia
    • Blood cultures if pyrexial
    • Alpha-1-antitrypsin levels
    • Theophylline level if on maintenance therapy
  • ABG
    • Normal in mild disease
    • Hypoxia and hypercapnia in advanced disease
    • Respiratory acidosis +/- partial or full metabolic compensation
  • Imaging
    • CXR
      • Classically shows bullae, hyperinflation and flattened diaphragms but can be normal
    • CT (high resolution CT – HRCT)
      • Can do in expiration phase if looking for air trapping
  • Echo
    • Assess cardiac function (?cor pulmonare)
  • Lung function tests
    • High RV and TLC
    • Low VC
    • FEV1/FVC reduced (i.e. obstructive)
      • FEV1/FVC < 0.7, FVC < 0.8 predicted
    • Little reversibility with salbutamol: <15%
    • Low KCO
      • Carbon Monoxide gas transfer coefficient reduced in proportion to severity

 

Staging of Severity of COPD (click here for NICE guidelines)

 
NICE guidelines COPD severity

* Symptoms should be present to diagnose COPD

** Or FEV1 > 50 with respiratory failure

 

Management of acute exacerbations of COPD

Mild exacerbations can be treated with antibiotics and steroids in primary care (rescue packs). In hospital:

  • ABCDE
    • Monitoring, iv access, bloods (consider theophylline level)
    • Early CXR and ABG
    • Cultures if pyrexial
  • Oxygen
  • Bronchodilators
    • Salbutamol 5mg
      • Nebulised (or inhaled via spacer – equally effective)
    • Ipratropium 0.5mg
      • No evidence this is more effective than salbutamol
  • Prednisolone 30mg
    •  7-14 days
      • No advantage in a more prolonged course
  • Antibiotics
    • If febrile, sputum purulent or signs of consolidation
      • Treat as pneumonia if consolidation on CXR
      • Empirical treatment – aminopenicillin, macrolide or tetracycline – refer to local guidelines
  • IV Thephylline
    • Only if no response to bronchodilator therapy
  • Non-invasive ventilation (CPAP or BiPAP)
    • In patients who are still hypercapnic and hypoxic despite medical therapy
    • Has been shown to improve survival
    • Must clearly document plan for what should happen if further deterioration and ceiling of treatment
    • Contraindications
      • Confusion or agitation
        • Unless this is due to high CO2
      • Severe dementia
      • Facial burns or trauma
      • Vomiting
      • Undrained pneumothorax
      • Copious secretions
      • Haemodynamically unstable, moribund or low GCS
        • Unless in HDU
      • Upper GI surgery or obstruction
  • Doxapram if NIV not available or inappropriate
    • Stimulant of chemoreceptors. CI in epilepsy.
  • Invasive ventilation – careful consideration regarding whether appropriate
  • Hospital at Home/ Assisted discharge programmes

 

Chronic management of COPD

  • Inhaled therapy
    • Short acting bronchodilators
      • Salbutamol 200mcg prn
      • Anticholinergic – e.g. Ipratropium
      • Combination of both
    • If patient remains breathless  or has exacerbations, offer the following as maintenance therapy:
      • If FEV1≥ 50% – either long acting β2 agonist (LABA) or long acting muscarinic antagonist (LAMA) e.g. tiotropium 18mcg od
      • If FEV1≤ 50% – either LABA with an inhaled corticosteroid (ICS) in a combination inhaler or LAMA e.g. Symbicort (budesonide and formeterol 400/12 bd) or Seretide (fluticasone and salmeterol 500/25 bd)
        • NB – use of ICS can increase risk of infection
      • Add LAMA to LABA + ICS in patients who remain breathless or have exacerbations despite taking LABA+ICS, irrespective of their FEV1
  • Theophylline
    • Sould only be used after a trial of short acting bronchodilators and LABAs, or in patients unable to use inhaled therapy
  • Oral mucolytic therapy
    • Consider in patients with productive cough
  • Long term nebulisers
  • Long Term Oxygen Therapy (LTOT)
    • Needs to use for at least 15 hours per day for any benefit and greater benefit if used for > 20 hours
    • Indications:
      • PaO2 on air when stable <7.3 or
      •  PaO2 on air when stable 7.3-8.0 with:
        • Secondary polycythaemia
        • Pulmonary HTN
        • Cor pulmonale
        • Nocturnal hypoxia (Sats <90% for >30% time)
  • Ambulatory oxygen therapy
    • Considered in patients who have exercise desaturation, are shown to have an improvement in exercise capacity and/or dyspnoea with oxygen and have motivation to use oxygen
    • Not recommended if PaO2 > 7.3
  • Non-invasive ventilation (NIV)
    • Refer patients with chronic hypercapnic respiratory failure who have required assisted ventilation during an exacerbation or who are hypercapnic or acidotic on LTOT to a specialist centre for consideration of long-term NIV.
  • Surgery
    • Bullectomy – consider in  patients who are breathless and have a single large bulla on a CT scan and an FEV1 <50% predicted
    • Lung volume reduction surgery – Consider if FEV1 > 20%, PaCO2 < 7.3, predominantly upper lobe emphysema, TLCO > 20% predicted
    • Lung transplantation – Take into consideration age, co-morbidities, FEV1, PaCO2, homogenously distributed emphysema on CT scan, elevated pulmonary artery pressures with progressive deterioration
  • MDT approach – Respiratory Nurse Specialist, Physio (Positive expiratory pressure masks, active cycle breathing)
  • Smoking cessation
  • Immunisations – pneumococcal and influenza
  • Self-management advice and packs – encourage patients to respond promptly to symptoms of an exacerbation by:
    • Starting oral corticosteroid if increased breathlessness interfering with daily activities
    • Starting antibiotics if purulent sputum
    • Adjusting bronchodilator therapy
    • Contacting healthcare professional if no improvement in symptoms
  • Pulmonary rehab
    • Multidisciplinary programme that is individually tailored to optimise each patient’s physical and social performance
    • Incorporates a programme of physical training, disease education, nutritional, psychological and behavioural intervention
  • Manage associated anxiety and depression
  • Optimise nutritional factors
  • Palliative care – In patients with end-stage COPD which is unresponsive to other medical therapy:
    • Opioids , Benzodiazepines, Tricyclic anti-depressants
    • Access to palliative care team/ hospices

 

Complications of COPD

  • Progressive respiratory failure
  • Cor Pulmonale
  • Recurrent LRTIs
  • Pneumothoraces
  • Post-infective bronchiectasis
  • Acute renal failure (likely pre-renal)

 

Prognosis of COPD

  • Mortality is 70 per 100,000 per year (down from 200 25 years ago)
  • 5 year survival approx. 75%
  • With acute exacerbations
    • 1/3 will be re-admitted within 3 months and 14% will die within 3 months

 

Click here for medical student OSCE and PACES questions about Chronic Obstructive Pulmonary Disease (COPD)

Common Chronic Obstructive Pulmonary Disease (COPD) exam questions for medical students, finals, OSCEs and MRCP PACES

 

Click here to download free teaching notes on COPD: Chronic Obstructive Pulmonary Disease (COPD)

Perfect revision for medical students, finals, OSCEs and MRCP PACES