COPD

Question 1

definition of COPD

Answer 1

Chronic, progressive lung disorder characterized by airflow obstruction (FEV1<80% predicted; FEV1/FVC<0.7), with little or no reversibility; with the following:

chronic bronchitis: Chronic cough and sputum production on most days for at least 3months per year over 2 consecutive years, symptoms improve if stop smoking, no excess mortality if lung function is normal ; and/or

Emphysema: Pathological diagnosis of permanent destructive enlargement of air spaces distal to the terminal bronchioles, destruction of alveolar walls - defined histologically but often seen on CT

Question 2

aeitiology of COPD

Answer 2

bronchial and alveolar damage from env toxins eg cigarette smoke

rare cause is a1-antitrypsin deficiency (<1%) - should be considered in young/people never smoked

overlaps and may co-present with asthma

chronic bronchitis: narrowing of airways from bronchiole inflammation (bronchiolitis) and bronchi with mucosal oedema, mucous hypersecretion and squamous metaplasia

emphysema: destruction and enlargement of the alveoli = loss of elastic traction that keeps small airways open in expiration, progressively larger spaces develop called bullae (diameter >1cm)

Question 3

epidemiology of COPD

Answer 3

very common - prevalence up to 8%

middle age/later

more common in males, likely to change with increase in female smokers

10–20% of the over-40s; 2.5≈106 deaths/yr worldwide

Question 4

presenting symptoms of COPD

Answer 4

chronic cough with sputum production

breathlessness

wheeze

reduced exercise tolerance

usually pts have COPD or asthma - not both. COPD more likely in:

• >35yrs at presentation
• sputum production
• smoking or pollution related
• chronic dyspnoea
• minimal diurnal or day-day FEV1 variation

Question 5

signs of COPD

Answer 5

inspection

• resp distress
• tachypnoea
• use of accessory muscles
• barrel-shaped overinflated chest
• reduced cricosternal distance (<3cm)
• cyanosis
• hyperinflation
• reduced expansion

percussion

• hyper-resonant chest
• loss of liver and cardiac dullness

auscultation

• quiet breath sounds eg over bullae
• prolonged expiration
• wheeze
• rhonchi and crepitations sometimes present

signs of CO2 retention

• bounding pulse
• warm peripheries
• flapping tremor of hands (asterixis)
• in late stages
  
  • signs of RHF eg R ventricular heave, raised JVP, ankle oedema

cor pulmonale

Question 6

pink puffers COPD

Answer 6

increased alveolar ventilation, a near normal PaO2 and a normal or low CO2

breathless but not cyanosed

may progress to type 1 resp failure

Question 7

blue bloaters COPD

Answer 7

low alveolar ventilation

low O2 and high CO2

cyanosed but not breathless

may go on to develop cor pulmonale

respiratory centres are relatively insensitive to CO2 and they rely on hypoxic drive to maintain respiratory eff ort - supplementary oxygen should be given with care

Question 8

investigations for COPD

Answer 8

spirometry and pulmonary function tests

• obstructive picture = low PEFR, low FEV:FVC ratio (mild, 60–80%; moderate, 40–60%; severe,<40%), increased lung volumes and CO gas transfer coefficient reduced when significant alveolar destruction
• air trapping
• FEV1<80% of predicted, FEV1 : FVC ratio <70%, high TLC, high RV, low DLCO in emphysema

CXR

• may appear normal or show hyperinflation (>6 ribs visible anteriorly, flat hemi-diaphragms)
• reduced peripheral lung markings
• elongated cardiac silhouette
• large central pulmonary arteries
• bullae

blood

• FBC (high HB and PVC as a result of secondary polycythaemia)

ABG

• may show hypoxia - low ox
• normal or high co2

ECG and echo

• for cor pulmonale
  
  • RA and RV hypertrophy

sputum and blood cultures

• in acute exacerbations for treatment

Considera1-antitrypsin levels in young patients or minimal smoking history.

CT

• bronchial wall thickening
• scarring
• air space enlargement

Question 9

clinical signs/symptoms of infective exacerbation of COPD

Answer 9

smoker

high temp

high RR

clubbing

wheeze and crepitation

productive cough

haematopsis

Question 10

management plan for COPD

Answer 10

stop smoking

exercise

diet advice +- supplements

mucolytics may help chronic productive cough

bronchodilators - short acting B2-agonists (salbutamol) and anticholinergics (ipratropium) delivered by inhalers/nebulizers. Long acting bronchodilators should be used if >2 exacerbations per yr

steroids

• Inhaled beclometasone should be considered for all with FEV1<50% predicted or those with>2 exacerbations per year.
• regular oral steroids should be avoided but may be necessary for maintenance

pul rehab

oxygen therapy - only for those who stop smoking

• long term home ox therapy shown to improve mortality
• indications:
  
  • PaO2<7.3 kPa on air during a period of clinical stability.
  • PaO27.3–8.0 kPa and signs of secondary polycythaemia, nocturnal hypoxaemia, peripheral oedema or pulmonary hypertension.
• ox concentrations are more economical if used for >8hr/day

prevention of infective exacerbations

• pneumococcal and influenza vaccination

diuretics for oedema

Question 11

treatment of acute infectious exacerbations COPD

Answer 11

24% Ox via non-variable flow venturi mask

increase slowly if no hypercapnia and still hypoxic - measured by ABG

corticosteroids oral or inhaled

start empirical AB therapy if infection

resp physio to clear sputum

consider non-invasive ventilation in severe cases

bronchodilater therapy - symptom relief (wheeze from bronchial narrowing)

Question 12

complications of COPD

Answer 12

acute resp failure

acute exacerbations +- infections - particularly streptococcus pneumoniae, haemophilius influenzae

pul hypertension and RHF

pneumothorax (from bullae rupture)

secondary polycythaemia

cor pulmonale - oedema, raised JVP

lung carcinoma

Question 13

prognosis of COPD

Answer 13

75% if>60 years and FEV140–49% predicted.

severity assessment has implications for therapy and prognosis

• The BODE index (Body mass index, airflow Obstruction, Dyspnoea and Exercise capacity) helps predict outcome and number and severity of exacerbations.
• The Global Initiative for COPD (GOLD) categorizes severity of COPD into four stages (mild, moderate, severe, and very severe) based on post-bronchodilator FEV1% predicted, but it is not useful for predicting total mortality for 3 years of follow-up and onwards.

Question 14

most likely dx and why

• demonstrates hyperinflated lungs with flattening of the hemi-diaphragms (>7 anterior, >9 posterior ribs seen in the lung fields

Answer 14

COPD