COPD

Question 1

definition

Answer 1

a common progressive disorder characterised by airway obstruction (FEV1 <80% predicted, FEV1/FVC < 0.7) with little or no reversibility
includes chronic bronchitis and emphysema
doesn’t usually occur alongside asthma

Question 2

COPd is favoured by:

Answer 2

age at onset >35yo
smoking (passive or active)
pollution related
chronic dyspnoea
sputum production
minimal diurnal or day to day FEV1 variation

Question 3

chronic bronchitis

Answer 3

cough and sputum production on most days for 3 months of 2 successive years
Sx improve if stop smoking
no excess mortality if lung function is normal

Question 4

emphysema

Answer 4

histologically - enlarged air spaces distal to terminal bronchioles, with destruction of alveolar walls

Question 5

prevalence of COPD

Answer 5

10-20% of the over 40s

2.5m deaths a year worldwide

Question 6

pink puffers

Answer 6

increased alveolar ventilation
near normal PaO2
normal/low PaCO2
breathless, but not cyanosed
may progress to type one resp failure (ie PaO2 <8kPa, normal PaCO2)

Question 7

blue bloaters

Answer 7

decreased alveolar ventilation
low PaO2
high PaCO2
cyanosed, but not breathless
may progress to type 2 resp failure (hypoxic and hypercapnic PaCO2 >6kPa)
may develop cor pulmonale

respiratory centres have reduced sensitivity to hypercapnia, so rely on their hypoxic drive to breath

Question 8

Sx of COPD

Answer 8

cough
sputum
dyspnoea
wheeze

Question 9

signs of COPD

Answer 9

tachypnoea and use of accessory muscles
hyperinflation
decreased cricosternal distance (<3cm)
decreased expansion
resonant or hyperresonant percussion
quiet breath sounds (over bullae)
wheeze
cyanosis
cor pulmonale

Question 10

complications of COPD

Answer 10

acute exacerbations +/- infection
polycythaemia (too many RBCs)
resp failure
cor pulmonale (raised JVP, oedema)
pneumothorax (ruptured bullae)
lung Ca

Question 11

bullae

Answer 11

markedly dilated (>1cm) air spaces within the lung parenchyma, secondary to COPD

Question 12

tests for COPD

Answer 12

FBC
PCV increased
CXR - hyperinflation, >6 anterior ribs seen above diaphragm in mid-clavicular line
flat hemidiaphragms
large central pulmonary arteries
decreased peripheral vascular markings
bullae
right and left ventricular hypertrophy

ABG: decreased PaO2 +/- hypercapnia

Question 13

Rx of COPD

Answer 13

mucolytics may help with cough

LTOT:
if PaO2 maintained >8kPa for 15h a day, 3 yr survival increases by 50%. should be given for:
1. stable non-smokers with PaO2 <7.3 despite max Rx
2. if PaO2 7.3-8.0 and pulmonary HTN, or polycythaemic, or peripheral oedema, or nocturnal hypoxia
3.terminally ill patients

Question 14

severity of COPD

Answer 14

mild - FEV1 >80%
mod - 50-79%
severe - 30-49%
very severe - <30%

all with FVC<0.7

Question 15

role of steroids

Answer 15

if the COPD is steroid responsive, 30mg prednisolone a day for 2 weeks can raise FEV1 by 15%. these patients may benefit from long term inhaled steroids

Question 16

indications for specialist referral

Answer 16

uncertain diagnosis, or suspected severe COPD
rapid decline in FEV1
cor pulmonale
bullous lung disease (surgery)
assessment for oral corticosteroids, nebs or LTOT
<10 pack years smoking Hx or less than 40yo (ie is the cause alpha1 anti-trypsin deficiency)
Sx disproportionate to lung function tests
freq infections

Question 17

pack years

Answer 17

number of packs a day x number of years smoking

Question 18

alpha-1 anti-trypsin deifciency

Answer 18

A1AT is a glycoprotein and one of a family of SERine Protease INhibitors made in the liver that control inflammatory cascades. deficiency is called a serpinopathy
commonly affects the lung and liver (cirrhosis and hepatocellular Ca)
in the lung it protects against damage from neutrophil elastase - a process also induced by cigarette smoking