2. Asthma

Question 1

Name the components that make up the conducting portion of the lungs?

Answer 1

Nostril
Nasal Cavities
Oral Cavity
Pharynx (nasopharynx, oropharynx and laryngopharynx)
Larynx 
Trachea
Primary bronchi
Secondary bronchi
Tertiary bronchi
Bronchioles
Terminal bronchioles

Question 2

Name the components that make up the respiratory portion of the lungs?

Answer 2

Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli

Question 3

Describe the structure of the trachea.

Answer 3

• Wide flexible tube
• Contains 20 tracheal cartilages which are C-shaped rings of hyaline cartilage
• Gap between rings is made up by the trachealis muscle

Question 4

In the bronchioles, what are the goblet cells replaced by? What function does it perform

Answer 4

Clara cells which secrete surfactant that prevent alveoli collapse

Question 5

Parasympathetic innervation to the smooth muscle in the walls of the airways causes the muscles to do what?

Answer 5

Causes them to contract, thus the airways narrow

Question 6

What are type 1 pneumocytes and where are they found?

Answer 6

They are found in the alveoli of the lungs

They are large flattened cells making up 95% of total alveolar area, are they present a very thin diffusion barrier for gases.

Question 7

What are type 2 pneumocytes and where are they found?

Answer 7

They are found in the alveoli of the lungs.

Despite making up 5% of the total alveolar area, they make up 60% of total number of cells.

They secrete ‘surfactant’ which decreases the surface tension between the thin alveolar walls, and stops alveoli collapsing when you breathe out.

Question 8

Describe asthma.

Answer 8

Asthma is a chronic inflammatory condition of the airways that causes episodic exacerbations of bronchoconstriction.

In asthma there is reversible airway obstruction that typically responds to bronchodilators such as salbutamol. This bronchoconstriction is caused by hypersensitivity of the airways and can be triggered by environmental factors.

Question 9

How can asthma be categorised?

Answer 9

• Atopic or Non- Atopic
• Intermittent or Persistant.

Atopic means triggered by the environment, which is most common form. It is mediated by systemic IgE production

Non-atopic is intrinsic, meaning its not caused by exposure to an allergen and is far less common. The inflammation is mediated by local IgE production

Question 10

What T-helper cell is normally found in the lung? Which one is found in those with asthma? Whats the difference between them?

Answer 10

Normally its T-helper 1, which promotes inflammation by increasing cell mediated immunity.

However in asthma its T-helper 2, which promotes inflammation by increasing humoral immunity (antibody production)

Question 11

What is the triad of asthma characteristics?

Answer 11

1. Smooth muscle contraction
2. Smooth muscle hypertrophy
3. Mucus hyper-secretion

Question 12

What are the risk factors of asthma?

Answer 12

• Family history of asthma
• A history of having atopic conditions
• Allergies
• Nasal polyps
• GORD
• Obesity

Question 13

What are typical triggers for an asthma attack?

Answer 13

• Infection
• Night time or early morning
• Exercise
• Animals
• Cold/damp weather
• Dust / pollen
• Strong emotions

Question 14

What are the symptoms of asthma?

Answer 14

• Shortness of breath
• Wheeze
• Chest Tightness
• Dry Irritating cough

Question 15

How is the wheeze in asthma described?

Answer 15

Bilateral widespread “polyphonic” wheeze

Question 16

According to NICE, how should asthma be diagnosed?

Answer 16

Asthma should never be diagnosed without definitive testing.

First line tests include

• Fractional exhaled nitric oxide (FeNO) - Levels of nitric oxide in breath increases with inflammation. A level over 40 parts per billion (ppb) is a positive test for an adult, and 35 ppb for a child.
• Spirometry with bronchodilator reversibility - A FEV1/FVC ratio of less than 70% is considered as a positive test for obstructive airway disease. These individuals are then offered a bronchodilator. If they have an improvement in FEV1 of 12% or more, plus an increase in volume of 200ml or more, then it’s a positive test.

Question 17

According to NICE, how should asthma be managed?

Answer 17

1. Add short-acting beta 2 agonist inhaler (e.g. salbutamol) as required for infrequent wheezy episodes.
2. Add a regular low dose inhaled corticosteroid.
3. Add an oral leukotriene receptor antagonist (i.e. montelukast).
4. Add LABA inhaler (e.g. salmeterol). Continue the LABA only if the patient has a good response.
5. Consider changing to a maintenance and reliever therapy (MART) regime.
6. Increase the inhaled corticosteroid to a “moderate dose”.
7. Consider increasing the inhaled corticosteroid dose to “high dose” or oral theophylline or an inhaled LAMA (e.g. tiotropium).
8. Refer to a specialist.

Question 18

What long term management do asthma patients require?

Answer 18

• Individual asthma self-management programme
• Yearly flu jab and pneumococcal vaccination
• Yearly asthma review
• Advise exercise and avoid smoking

Question 19

What 3 questions are important during an annual asthma review?

Answer 19

1. In the last month have you had difficulty sleeping due to your asthma (including cough symptoms, shortness of breath)?
2. Have you had your usual asthma symptoms (eg, cough, wheeze, chest tightness, shortness of breath) during the day?
3. Has your asthma interfered with your usual daily activities (eg, school, work, housework)?

Question 20

How is an acute asthma attack graded?

Answer 20

Moderate : 50-75% predicted PEFR. This is the only criteria for a moderate asthma attack

Severe : 33-50% predicted PEFR

Life-threatening : <33% predicted PEFR

Question 21

What are the criteria for a severe asthma attack vs a life threatening asthma attack

Answer 21

Severe

• PEFR 33-50% predicted
• Resp rate >25
• Heart rate >110
• Unable to complete sentences

Life-Threatening

• PEFR <33%
• Sats <92%
• Becoming tired
• No wheeze. This occurs when the airways are so tight that there is no air entry at all. This is ominously described as a “silent chest”.
• Haemodynamic instability (i.e. shock)

Question 22

What is the treatment for a moderate asthma attack?

Answer 22

• Nebulised beta-2 agonists (i.e. salbutamol 5mg repeated as often as required)

Nebulised ipratropium bromide

Steroids. Oral prednisolone or IV hydrocortisone. These are continued for 5 days

Antibiotics if there is convincing evidence of bacterial infection

Question 23

What is the treatment for a severe asthma attack?

Answer 23

Oxygen if required to maintain sats 94-98%

Aminophylline infusion - done under senior guidance

Consider IV salbutamol - done under senior guidance

Question 24

What is the treatment for a life-threatening asthma attack?

Answer 24

IV magnesium sulphate infusion - done under senior guidance

Admission to HDU / ICU

Intubation in worst cases – however this decision should be made early because it is very difficult to intubate with severe bronchoconstriction

Question 25

What should an asthma patients arterial blood gas report look like initially?

Answer 25

They will have respiratory alkalosis as they are tachypneic so are blowing a lot of CO2 off

Question 26

What is a concerning arterial blood gas report for someone having an asthma attack?

Answer 26

A normal pCO2 or hypoxia is a concerning sign as it means they are tiring and indicates life threatening asthma. A respiratory acidosis due to high CO2 is even worse and is a very very bad sign

Question 27

What factors can you monitor to assess a patients response to asthma treatment?

Answer 27

``` Respiratory rate Respiratory effort Peak flow Oxygen saturations Chest auscultation ```

Question 28

When someone who had an asthma attack is discharged, what should you give them in addition to any ongoing medications?

Answer 28

- An Asthma action plan providing all the information they need on their asthma in one place - A 'Rescue Pack' of steroids incase they have another exacerbation - Tell them to see their GP within 2 days ideally

Question 29

According to NICE, When should you refer an asthma patient to a respiratory specialist?

Answer 29

After 2 attacks in 12 months

Question 30

Why do you need to monitor serum potassium levels when an individual is on salbutamol?

Answer 30

It causes potassium to be absorbed from the blood into the cells It also causes tachycardia

Question 31

What is an obstructive lung disease and give some examples

Answer 31

When the lungs are unable to expel air properly during exhalation - Asthma - Bronchiectasis - COPD

Question 32

What is a restrictive lung disease

Answer 32

Lungs are unable to fully expand, so limit the amount of oxygen taken in during inhalation

Question 33

Spirometry: describe the changes that you would see in obstructive lung disease in terms of; FEV1 FVC FEV1/FVC ratio

Answer 33

FEV1: normal or decreased FVC: normal or decreased FEV1/FVC ratio: decreased (less than 70%)

Question 34

Spirometry: describe the changes that you would see in restrictive lung disease in terms of; FEV1 FVC FEV1/FVC ratio

Answer 34

FEV 1: normal or decreased FVC: decreased FEV1/FVC ratio: normal or increased (above 70%)

Question 35

Knowing that the medication is correct for this patient, why may they still be having asthma attacks?

Answer 35

- It may be an incorrect diagnosis - Lack of adherence to medication - Poor inhaler technique - Carrying on with smoking

Question 36

How would COPD present differently to asthma?

Answer 36

- would have a history of smoking or long-term asthma - dyspnoea occurs with or without wheezing and coughing - examination will show barrel chest, hyper resonance to percussion and distant breath sounds

Question 37

If you have nasal polyps, what are you at risk of getting? What else could it indicate?

Answer 37

They are a risk factor for asthma. They can also be present in those with diagnosed asthma.

Question 38

What is a maintenance and reliever therapy (MART) regime?

Answer 38

This is a combination inhaler containing a low dose inhaled corticosteroid and a fast acting LABA. This replaces all other inhalers and the patient uses this single inhaler both regularly as a “preventer” and also as a “reliever” when they have symptoms.

Question 39

How does theophylline work?

Answer 39

This works by relaxing bronchial smooth muscle and reducing inflammation.

Question 40

Why is theophylline not commonly used for the management of asthma in the community?

Answer 40

Unfortunately it has a narrow therapeutic window and can be toxic in excess so monitoring plasma theophylline levels in the blood is required. This is done 5 days after starting treatment and 3 days after each dose changes.