COPD

Question 1

what is a pack year

Answer 1

number of packs x number of years smoked

20 cigs = 1 pack

Question 2

what is COPD?

Answer 2

airflow obstruction with little to no reversibility

includes chronic bronchitis and emphysema

Question 3

what is chronic bronchitis

Answer 3

cough and sputum production on most days for 3 months, of 2 successive years

Question 4

what is emphysema

Answer 4

enlarged air spaces distal to terminal bronchioles; destruction of alveolar walls

may join together to form a bullae that ruptures and causes a pneumothorax

Question 5

difference between COPD and asthma

Answer 5

both obstructive diseases but asthma is reversible

Question 6

what are the causes of COPD

Answer 6

genetics:
- alpha-1-anti-trypisin deficiency (Still need to smoke) = A1AT protects against tissue damage from neurtrophil elastase which is induced by smoking

other gene polymorphisms eg those against metaloproteinases that protect lung against inflammation

active and passive smoking, cannabis, biomass fuels

Question 7

what are the 3 pathological changes to the lungs and the main features of COPD

Answer 7

goblet cell hyperplasia, causing cough and sputum
airway narrowing causes breathlessness and wheeze
alveolar destruction

main features: bronchoconstriction, musocal oedema and mucosal hypersecretion

Question 8

pathogenesis of COPD?

Answer 8

epithelial cells allows entry of cig smoke
macrophages and dendritic cells = activation of IS
proteases cause mucus production
damage lungs
fibroblasts scar airways

Question 9

why do you get type 2 resp failure in COPD?

Answer 9

• loss of elastic recoil
• gas trapping and reduce excretion of CO2
• forms carbonic acid in blood
• progressive CO2 retention = compensation by kidneys reabsorbing more bicarbonate to neutralise it

-but CO2 will always be high and SOB = low oxygen levels

Question 10

what are the symptoms of COPD?

Answer 10

smoker or ex-smoker >35

exertional breathlessness
chronic cough
regular sputum production
winter exacerbations
wheeze

Question 11

what are the physical signs of COPD

Answer 11

tar staining
central cyanosis 
tachypnea 
chest hyperexpansion = BARREL SHAPED
cor pulmonale
wheeze
palpable liver edge
use of acessory muscle on inspiration

Question 12

how do you stage COPD

Answer 12

GOLD stages, based on FEV1 ratio

1>80%
2 50-79%
3 30-49%
4<30%

Question 13

what is the BODE index?

Answer 13

predicts survival in COPD patients, based on FEV1% of predicted, 6 minute walk distance, BMI, and mMRC dyspnea scale

Question 14

what are the investigations you do for COPD?

Answer 14

spirometry
ABGS
CXR
CT

Question 15

how are ABGS used in COPD

Answer 15

• always check pH first
• may find both types of resp failure
• after that, check compensation:
• compensated if HCO3 is abnormal; if raised = degree of chronicity but if pH is low it has not compensated

BE = metabolic component? if infection, BE is low

Question 16

what is type 1 resp failure

Answer 16

• low oxygen
• hypoxaemic failure, <8kPa
• underlying pathology with LUNGS eg infection, oedema or shunt

Question 17

what is type 2 resp failure and what are the clinical features?

Answer 17

low oxygen and high co2
-may lead to low pH and high CO3

-dilated pupils, bounding pulse, hand flap, myoclonus, confusion and drowsiness

Question 18

what would you see on a CXR of COPD

Answer 18

often normal but exclude other conditions

low, flattened diaphragms
nipple shadows 
smaller heart size
horizontal ribs 
hyper-expansion

Question 19

what would you see on a CT scan of COPD

Answer 19

holes or bullae suggesting emphysema (in apices)

bronchial wall thickening

Question 20

how is COPD used in spirometry

Answer 20

measures VC and FVC (refer to asthma flashcards)

Question 21

how do you differentiate between asthma and COPD?

Answer 21

using spirometry

• asthma will have:
• a large response >400ml to bronchodilators or 30mg oral prednisolone daily for 2 weeks
• serial peak flow measurements showing >20% diurnal variability
• night time waking with breathlessness or wheeze

Question 22

what happens if a COPD patient stops smoking?

Answer 22

lung function stops declining as quickly but not reversible so symptoms will still prevent but just later in life

Question 23

what is cor pulmonale and why do you get it

Answer 23

it is right sided heart failure as a result of chronic hypoxic lung disease

• hypoxia
• pulmonary arterial vasoconstriction
• increased pulmonary artery pressure
• RV hypertrophy
• RV failure

Question 24

how do you treat COPD?

Answer 24

-STOP SMOKING

• start SABA
• if still breathless, add LABA or anti-muscarinic in preference to SAMA (LAMA)
• if FEV1 ratio <50% or frequent exacerbations add inhaled CCS in combined inhaler with LABA
• if still breathless consider pulmonary rehab, theophylline or high dose bronchodilators

Question 25

what other non-pharmacological treatments can you give to COPD patients

Answer 25

- flu and pneumococcal vaccine - oxygen short burst for symptoms if >15 hours a day - physio for breathing may need bullectomy, lung volume reduction surgery or lung transplantation

Question 26

what are the complications of COPD

Answer 26

``` exacerbations pneumonia pneumothorax RVF peripheral neuropathy cachexia ```

Question 27

what causes a COPD exacerbation

Answer 27

viruses and bacteria such as H.influenzae, S.pnemonia, pseudomonas

Question 28

what are the symptoms of a COPD exacerbation

Answer 28

``` preceding coryzal symptoms increased breathlessness increased cough increased sputum sputum purulence ankle swelling ```

Question 29

wha investigations would you do in a COPD exacerbation

Answer 29

``` CXR ABG or o2 sats ECGs FBC, U&Es, CRP sputum culture ```

Question 30

how do you manage a COPD exacerbation

Answer 30

- oxygen, SaO2 not more than 94% in selected cases if hypercapnic - high dose SABA, nebulised - high dose CCS (prednisolone 40mg/day - 7 days) to reduce inflammation - antibiotic ONLY if purulent sputum reassess after an hour

Question 31

what do you do if, after an hour, a COPD exacerbation patient is still in resp acidosis?

Answer 31

- IV bronchodilator: salbutamol or theophylline - ICU - non invasive ventilation - then intubation or assisted ventilation

Question 32

what are the 3 ways of oxygen delivery devices

Answer 32

nasal cannulae: 60% delivery, max oxygen 5L oxygen/minute non-rebreathing mask - control of acute patients, 15L/min = 85% of FiO2 - cannot regulate amount of inspired oxygen but once initial assessment is complete, reduce oxygen to appropriate target sats of 94-98% venturi mask - exact control of FiO2, and avoids over-oxygenation