COPD

Question 1

How is COPD defined?

Answer 1

A disease state characterised by airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases

Question 2

What causes COPD?

Answer 2

COPD is caused by long-term exposure to toxic particles and gases

In developed countries, cigarette smoking accounts for over 90% of cases

Question 3

What is the most consistent pathological finding in COPD?

Answer 3

The most consistent pathological finding in COPD is increased numbers of mucus-secreting goblet cells in the bronchial mucosa, especially in the larger bronchi

In more severe cases, the bronchi become overtly inflamed and pus is seen in the lumen

Question 4

What part of the airways is mainly affected in COPD?

Answer 4

The small airways are particularly affected early in the disease, initially without the development of any significant breathlessness.

This initial inflammation of the small airways is reversible and accounts for the improvement in airway function if smoking is stopped early.

In later stages the inflammation continues, even if smoking is stopped

Question 5

What microscopic changes can be seen in COPD?

Answer 5

Infiltration of the walls of the bronchi and bronchioles with acute and chronic inflammatory cells → lymphoid follicles may develop in severe cases

Further progression of the airways disease leads to progressive squamous cell metaplasia, and fibrosis of the bronchial walls

Question 6

What is emphysema?

Answer 6

Emphysema is defined as abnormal, permanent enlargement of air spaces distal to the terminal bronchiole, accompanied by destruction of their walls and without obvious fibrosis. Emphysema leads to expiratory airflow limitation and air trapping

Question 7

What does the loss of lung elastic recoil result in in COPD?

Answer 7

The loss of lung elastic recoil results in an increase in total lung capacity. Premature closure of airways limits expiratory flow while the loss of alveoli decreases capacity for gas transfer.

Question 8

What loss ini FEV1 can be seen in COPD patients, compared to normal individuals?

Answer 8

There is a loss of 50mL per year in FEV1 in patients with COPD compared to 20mL per year in healthy people

Question 9

What mechanisms (3) have been suggested for the limitation of airflow in the small airways in COPD?

Answer 9

1. Loss of elasticity and alveolar attachments of airways due to emphysema. This reduces the elastic recoil and the airways collapse during expiration.
2. Inflammation and scarring cause the small airways to narrow.
3. Mucus secretion, which blocks the airways.

Question 10

What three factors contribute to the pathogenesis of COPD?

Answer 10

1. Cigarette smoking
2. Infections
3. alpha-antitrypsin deficiency

Question 11

What do bronchoalveolar biopsies in COPD patients reveal histologically?

Answer 11

Bronchoalveolar lavage and biopsies of the airways of smokers show increased numbers of neutrophil granulocytes. These granulocytes can release elastases and proteases, which may help to produce emphysem

Question 12

How does smoking contribute to the development of COPD?

Answer 12

α1-Antitrypsin is a major serum antiprotease which can be inactivated by cigarette smoke

It has been suggested that an imbalance between protease and antiprotease activity causes the damage

Mucous gland hypertrophy in the larger airways is thought to be a direct response to persistent irritation resulting from the inhalation of cigarette smoke. The smoke has an adverse effect on surfactant, favouring overdistension of the lungs.

Question 13

What are the characteristics symptoms of COPD?

Answer 13

1. Productive cough with white or clear sputum
2. Wheeze
3. Breathlessness

Question 14

What factors worsen the symptoms in COPD?

Answer 14

Symptoms can be worsened by cold, foggy weather and atmospheric pollution

With advanced disease, breathlessness is severe even after mild exercise such as getting dressed. Apart from the pulmonary features, there are systemic effects including hypertension, osteoporosis, depression, weight loss and reduced muscle mass with general weakness.

Question 15

What are the signs of COPD?

Answer 15

In mild COPD, there may. be no signs or just a quiet wheeze throughout the chest.

In severe disease there are more signs:

1. Tachypnoeic
2. Prolonged expiration
3. Use of accessory muscles during inspiration
4. Pursing of the lips on expiration
5. Poor chest expansion and lungs are hyper-inflated, leading to hyper-resonance
6. Loss of normal cardiac and liver dullness

Question 16

What happens to the respiratory quality in the later stages of COPD?

Answer 16

The later stages of COPD are characterised by the development of respiratory failure.

For practical purposes this is said to occur when there is either a PaO2 <8 kPa (60 mmHg) or a PaCO2 >7 kPa (55 mmHg).

Question 17

What is one of the complications in late-stage COPD?

Answer 17

Cor pulmonale

Question 18

What is cor pulmonale?

Answer 18

Patients with advanced COPD may develop cor pulmonale, which is defined as symptoms and signs of fluid overload secondary to lung disease.

The fluid retention and peripheral oedema is due to failure of excretion of sodium and water by the hypoxic kidney rather than heart failure.

Question 19

What is cor pulmonale characterised by?

Answer 19

It is characterised by pulmonary hypertension and right ventricular hypertrophy.

Initially there may be a prominent parasternal heave, due to right ventricular hypertrophy, and a loud pulmonary second sound.

In very severe pulmonary hypertension, the pulmonary valve becomes incompetent.

Question 20

What are late-stage complications of fluid overload secondary to cor pulmonale?

Answer 20

With severe fluid overload, tricuspid incompetence may develop with a greatly elevated jugular venous pressure (JVP), ascites and upper abdominal discomfort due to liver swelling.

Question 21

How is a COPD diagnosis made?

Answer 21

Usually based on history of:

1. Breathlessness
2. Sputum production
3. Chronic smoking

In absence of smoking, asthma is a more likely diagnosis, unless there is a family history of alpha-antitrypsin deficiency

No individual clinical feature is diagnostic. Patient may have signs of:

1. Hyperinflation
2. Pursed lips respiration
3. Barrel chest

Question 22

What investigations are appropriate for suspected COPD?

Answer 22

1. Lung function test (FEV1: FVC <0.7)

2. Chest X-ray (often normal)

Question 23

What is the management of COPD?

Answer 23

1. Smoking cessation!

2. Drug therapy

Question 24

What is the drug therapy pathway for people with COPD?

Answer 24

1. SABA or SAMA

2A. IF FEV >50% and no asthmatic features then LABA + LAMA
2B. IF FEV < 50% and asthmatic features, then LABA +ICS

3. LABA + LAMA + ICS

Question 25

Name a sama

Answer 25

ipratropium

Question 26

Name a lama

Answer 26

tiotropium

Question 27

What is the mechanism of action for LAMA or SAMAs?

Answer 27

Inhibition of the M3 muscarinic receptors in the smooth muscle of the lungs leads to relaxation of smooth muscle and bronchodilation

Question 28

What dose tiotropium would you prescribe?

Answer 28

5 micrograms once daily inhaled

Question 29

What dose ipratropium would you prescribe?

Answer 29

Nebulised 250-500 micrograms, 3-4 times a day

Question 30

What corticosteroid would you give COPD patients?

Answer 30

Prednisolone 30 mg daily should be given for 2 weeks, with measurements of lung function before and after the treatment period

Question 31

What is the use for antibiotics in COPD?

Answer 31

Prompt antibiotic treatment shortens exacerbations and should always be given in acute episodes as it may prevent hospital admission and further lung damage

Question 32

What are features suggestive of an acute exacerbation of COPD?

Answer 32

Worsening breathlessness.
Increased sputum volume and purulence.
Cough.
Wheeze.
Fever without an obvious source.
Upper respiratory tract infection in the past 5 days.
Increased respiratory rate or heart rate increase 20% above baseline.

Question 33

What are symptoms associated with a severe acute exacerbation in COPD?

Answer 33

Marked breathlessness and tachypnoea.
Pursed-lip breathing and/or use of accessory muscles at rest.
New-onset cyanosis or peripheral oedema.
Acute confusion or drowsiness.
Marked reduction in activities of daily livi

Question 34

What investigations would you do for a suspected exacerbation of COPD?

Answer 34

Check vital signs (including temperature, oxygen saturations [using pulse oximetry], blood pressure and heart rate).
Assess for confusion or impaired consciousness.
Examine the chest.
Check ability to cope at home.

Question 35

What O2 would you use for COPD patients?

Answer 35

Venturi 24% mask at 2-3 l/min or Venturi 28% mask at a flow rate of 4 l/min or nasal cannula at a flow rate of 1-2 l/min (if a 24% mask is not available).

Question 36

What is the target O2 saturation for patients with COPD?

Answer 36

88-92%