18.1 Asthma and COPD

Question 1

Describe what asthma is.

Answer 1

A chronic inflammatory disease of the airways characterised by variability of symptoms and reversible airway obstruction.
Airways become narrowed due to bronchoconstriction and mucous hypersecretion.

Question 2

What are the clinical symptoms of asthma?

Answer 2

• Wheeze
• Chest tightness
• Cough
• Mucous production
• Shortness of breath
• Airway hyper-responsiveness = twitchy/sensitive airways e.g. bronchospasm after entering a room filled with smoke

Question 3

How does airway obstruction reverse in asthma?

Answer 3

Can reverse spontaneously or due to treatment with beta-2-agonists or anti-inflammatory agents (corticosteroids)

Question 4

What factors influence the variability of asthma?

Answer 4

• Allergens
• Cigarette smoke
• Respiratory infection
• Exercise and hyperventilation
• Weather changes
• Air pollutants
• Food, additives, drugs
• Cold/damp

Question 5

Describe the epidemiology of asthma.

Answer 5

• Very common, affects at least 300 million people worldwide
• Responsible for 1 in every 250 deaths worldwide
• 15% prevalence in Western world

Question 6

What are some hypotheses for why asthma is becoming more common?

Answer 6

• Hygiene hypothesis (less bacteria, immune system less busy resulting in autoimmune response)
• Dust mites
• Pollution
• Polyunsaturated fats

Question 7

What are some risks for developing asthma?

Answer 7

• Genetics
• Maternal smoking
• Viral infections in infancy
• Pre-term birth

Question 8

Provide a simple overview of the pathophysiology of asthma.

Answer 8

More than 1 inflammatory pathway, more than 1 phenotype.
- Early onset asthma: associated with allergy, inflammation mediated by antigen binding to serum IgE
- Late onset asthma: non-allergy related, mediated by eosinophils and neutrophils

Question 9

Describe early onset asthma (allergy).

Answer 9

• Antigen binds to IgE
• Degranulation of mast cells
• Histamine release
• Leukotrine release
• Inflammation in airways

Question 10

Describe the cells involved in the pathophysiology of asthma.

Answer 10

• Neutrophils, mast cells, eosinophils, Th2 cells work together and upregulate inflammatory mediators
• Upregulates mucous secretion
• Sensory nerve activation = bronchoconstriction and hypertrophy of the smooth muscle
• Plasma leakage and oedema, also contributes to bronchoconstriction
• Over time, epithelial shedding occurs, can cause epithelial fibrosis if asthma is left untreated- permanent airway damage

Question 11

Summarise the causes of smooth muscle dysfunction and airway inflammation in asthma.

Answer 11

Question 12

How can airway obstruction be measured?

Answer 12

• Peak flow meter
• Spirometry

Question 13

How is asthma diagnosed?

Answer 13

There isn’t one test that accurately diagnoses asthma.
Thorough history is required.
Investigations are used to help to confirm a diagnosis.

Question 14

What is the typical presentation of a patient with asthma?

Answer 14

• History of intermittent and variable wheeze, cough, breathlessness
• Tend to get worse with exertion and specific triggers
• Symptoms tend to be worse at night as cortisol drops (anti-inflammatory and bronchodilator)
• Improves with salbutamol short term, steroids long term
• May have a history of atopy (rhinitis, eczema etc), family history
• Ask about occupation e.g. baker, paint sprayer, construction

Question 15

What investigations are carried out to support an asthma diagnosis?

Answer 15

• Ask patient to keep diary and record peak flow measurements
• Spirometry before and after salbutamol (beta 2 agonist), if FEV1 improves by 200ml and 15% they likely have asthma
• Exercise testing with pre and post spirometry
• Skin prick tests
• Blood tests (IgE levels/RAST)

Question 16

What are FEV1 and FVC?

Answer 16

FEV1 = forced expiratory volume in 1 second
FVC = forced vital capacity (the amount of air that can be forcibly exhaled from your lungs after taking the deepest breath possible)

FEV1 and FVC ratio is important, measured using spirometry.

Question 17

What are the aims of asthma management?

Answer 17

• No daytime symptoms
• No night-time awakening due to asthma
• No need for rescue medication
• No exacerbations
• No limitations on daily activity including exercise
• Normal lung function
• Minimal side effects from medication

Question 18

What are the consequences of poor asthma control?

Answer 18

• Exacerbations
• Development of chronic, irreversible asthma
• Epithelial fibrosis

Question 19

What closed questions should be asked by a dentist to an asthma patient?

Answer 19

• Have you had any daytime asthma symptoms recently?
• Have you needed to use your blue inhaler recently?
• Do you wake up in the middle of the night due to your asthma?
• Have you had an attack or needed emergency medical attention recently?

Question 20

What inhaled medication is used to manage asthma?

Answer 20

• Inhaled steroids are used as a long term preventer (e.g. beclamethasone- brown inhaler)
• Beta-2-agonist for immediate relief (e.g. salbutamol- blue inhaler)
• Pts begin with a low dose corticosteroid inhaler and the dose is increased if symptoms persist

Question 21

What non-inhaler treatment is used to manage asthma?

Answer 21

• Antihistamines
• Steroid tablets
• Aminophylline (bronchodilator)
• Montelukast
• Nebuliser
• Omalizumab injection (biological theropy which ‘mops up’ IgE)

Question 22

What may cause difficult asthma/poorly controlled asthma?

Answer 22

• Lack of compliance with inhalers
• Poor inhaler technique
• Incorrect diagnosis
• Peristent exposure to allergen or trigger?
• Concomitant allergic rhinitis
• Other drugs making asthma control worse e.g. beta blockers, NSAIDs
• Smoking, pollution, stress, occupation

Question 23

What is an asthma exacerbation?

Answer 23

• Sustained worsening of symptoms, usually accompanied by a fall in peak flow
• Either due to poor control or viral illness
• Can often lead to hospital admission

Question 24

What is chronic obstructive pulmonary disease?

Answer 24

A treatable and preventable condition, characterised by airflow obstruction, which is usually progressive- not fully reversible and does not change markedly over several months (unlike asthma which is a variable condition).

• Airflow obstruction is associated with an abnormal inflammatory response in the lungs in response to noxious stimuli
• Primarily affects the lungs but also produces systemic consequences

Question 25

What other systemic conditions are associated with COPD?

Answer 25

- Osteoporosis - Loss of fat free mass (cachexia) - Type 2 diabetes - Peptic ulcers - Cardiovascular disease - Chronic renal impairment

Question 26

What are the differences between chronic bronchitis, emphysema and COPD?

Answer 26

Doesn't necessarily include asthma, but asthma and COPD are likely to exist together.

Question 27

Describe the multi-component disease process of COPD.

Answer 27

- Noxious particles set up a cascade of epthileal damage - Direct inflammation of airway - Loss of elastic recoil - Airway obstruction - Difficult to get air out

Question 28

What are the consequences of COPD inflammation?

Answer 28

- Fixed airway obstruction, narrowing - Impaired gas exchange as alveoli are affected - Reduced exercise tolerance - Progressive deconditioning and disability - Recurrent infections and exacerbations - Respiratory failure (chronically low oxygen levels) - Pulmonary hypertension

Question 29

Describe the fatality rates of COPD.

Answer 29

- 3rd biggest killer worldwide Causes of death in COPD: - Pulmonary cause - Cardiovascular cause - Cancer - Other

Question 30

How is a COPD diagnosis made?

Answer 30

COPD diagnosis is considered in patients over 35 who: - Are smokers or ex-smokers - With symptoms including exertional breathlessness, chronic cough, regular sputum production, frequent winter ‘bronchitis’, wheeze - Have evidence of airflow obstruction on spirometry - Have no clinical features of asthma

Question 31

COPD vs asthma diagnosis.

Answer 31

Question 32

What are the differences in the inflammatory processes behind COPD vs asthma?

Answer 32

- Asthma: humoral immune pathway - COPD: cellular immune pathway

Question 33

At what age does FEV1 peak?

Answer 33

Age 25, then gradually decreases for the rest of your life.

Question 34

How is COPD severity graded?

Answer 34

Stage 1-4

Question 35

How is COPD managed?

Answer 35

- Smoking cessation - Inhaled therapy - Beta-2-agonists - Anti-cholinergic drugs - Combination inhalers - Oxygen therapy

Question 36

Explain smoking cessation in COPD management.

Answer 36

- Most beneficial and cost effective measure - Nicotine replacement therapy e.g. patches, lozenges - Bupropion can be prescribed but has severe side effects - Varenicline (Champix) can be prescribed to assist smoking cessation

Question 37

Describe the inhalers that can be used to manage COPD.

Answer 37

- Main treatment is bronchodilators e.g. beta-2 agonists: salbutamol (short term relief/SABA) salmeterol (longer term relief/LABA) - Anti-cholinergic drugs: ipratropium (SAMA) and tiotropium (LAMA) - Combination inhalers: inhaled corticosteroid + LABA. Indicated for frequent exacerbations. Potential risk of pneumonia.

Question 38

Describe oxygen therapy in the management of COPD.

Answer 38

- For pts with low oxygen levels, NOT for breathlessness - Over-prescribed, can be dangerous - Not to be given to smokers, fire hazard

Question 39

What other treatments can be used for COPD?

Answer 39

- Oral steroids - Theophylline - Mucolytics - Diuretics for cor pulmonale (right side heart failure)

Question 40

What are acute exacerbations of COPD?

Answer 40

- Increased severity of cough - Change in sputum volume and purulence - Increased dyspnoea - Wheeze, fatigue, oedema - 70-80% of cases due to infection - 20% idiopathic or due to air pollution

Question 41

Why are acute exacerbations of COPD important?

Answer 41

- Increased lung function loss - Worse health status - Patients experiencing frequent exacerbations have a worse prognosis - Approx. 40% of patients admitted to hospital due to exacerbation die within a year - Higher risk of mortality of COPD exacerbation compared to heart attack

Question 42

How is acute COPD exacerbation treated?

Answer 42

- Good supportive care, hydration, nutrition - Regular bronchodilation using short acting beta-2 agonist - Chest physiotherapy with mucolytic agents if mucous plugging is an issue - If they are hospitalised, they will be given oral steroids - Antibiotics not given needlessly (greener sputum = more likely antibiotics necessary)