Asthma

Question 1

Asthma

What is asthma in one sentence?

Answer 1

a chronic and inflammatory respiratory pathology characterised by recurring bronchial hyperresponsiveness and consequent airway narrowing, following exposure to specific triggers

Question 2

Asthma

What are some typical asthma triggers?

Answer 2

• Cold air
• Exercise
• Allergens
• Aspirin or other COX-1 inhibitors
• Viral infections

Question 3

Asthma

What 3 typical symptoms are caused by the narrowing of the bronchi.

Answer 3

dyspnoea, high-pitched wheezing and/or cough

Question 4

Asthma

What in a pt history might make asthma a more likely differential?

Answer 4

• relieved by bronchodilators or elimination of trigger
• intermittent and episodic
• worse at night
• diagnosed in childhood

Question 5

Asthma

How is a diagnosis of asthma made?

Answer 5

History
- dyspnoea, expiratory wheezing, cough (after exposure)
- airflow obstruction confirmed by spirometry with bronchodilator reversibility testing and Fractional exhaled nitric oxide

Question 6

Asthma

Name some differentials and how they might present differently to asthma

Answer 6

• COPD: the airflow obstruction is persistent and irreversible, the patient is generally older and a smoker (more than 20 pack years)
• Exertional dyspnoea
• Cardiomyopathies, coronary artery disease or pericarditis if chest pain or any cardiac symptoms added to classic asthma symptoms
• Bronchial carcinoma
• Aspiration of foreign body

Question 7

Asthma

What might spirometry show?

Answer 7

Reduced FEV₁:FVC ratio (usually less than 0.7)

Reversibility test: after an initial spirometry test with obstructive characteristics, administration of a short-acting bronchodilator and repetition of spirometry after 15 mins would show reversibility of airflow obstruction. To be certain of reversibility, FEV₁ would have to increase 12% or more with respect to the original value.
Bronchoprovocation test: used if spirometry test results are normal and involves administration of methacholine to provoke bronchoconstriction.

Question 8

Asthma

How might we used PEF for asthma diagnosis?

Answer 8

PEF is a poor diagnostic tool as it may not demonstrate airflow obstruction even if it is present on spirometry.

If PEF is lower than the predicted value, it could be indicative of asthma (unspecific).

If reduced PEF improves more than 20% after administration of a short-acting bronchodilator it is more specific for asthma diagnosis.

Question 9

Asthma

What might bloods show?

Answer 9

eosoinophilia (but not part of diagnosis)

Question 10

Asthma

Although allergy tests are not part of asthma diagnosis , what tests might help us identify triggers?

Answer 10

• Eosinophil count
• Total serum IgE
• Prick test

Question 11

Asthma

What are some bedside signs of severe asthma exacerbation?

Answer 11

• Tachypnoea (> 30 breaths/minute)
• Tachycardia (> 120 beats/minute)
• Use of accessory muscles to breathe
• Sweating
• Extreme dyspnoea
• Pulsus paradoxus

Question 12

Asthma

What tests are important to do when dealing with a pt in resp distress?

What might they show?

Answer 12

PEF, pulse oximetry and secondarily, arterial blood gas (ABG)

Hypoxaemia with PaO2 < 60 mmHg or SpO2 < 90% are signs of a severe asthma attack.
The respiratory drive will be increased in an acute asthma attack resulting in hyperventilation and hypocapnia initially, with progressive hypercapnia if the obstruction is not resolved.

Question 13

Asthma

What does emergency management consist of?

Answer 13

1. Resolving airflow obstruction: a combination of an inhaled bronchodilator and systemic glucocorticoid (effect of steroids is clinically seen up to 6 hours after administration)
2. Correcting hypoxaemia: supplemental oxygen, usually nasal cannula suffices

*If after 1 hour the symptoms have resolved and PEF > 80% of the predicted value, the patient is fit for discharge. *

Question 14

Asthma

How do we manage intermittent asthma? (prescribing)

Answer 14

SABA as needed

Salbutamol

Question 15

How do we manage mild persistent asthma? (prescribing)

Answer 15

SABA

+

low dose ICS
or
low dose ICS + LABA
or
leukotriene ICS (if glucocortcoid not recommended)

Question 16

How do we manage modernate persistent asthma? (prescribing)

Answer 16

SABA

+

low dose ICS + LABA
or
medium dose ICS
or
low dose ICS + LAMA (if LABA not recommended)
or
low dose ICS leukotriene modifier (if glucocortcoid not recommended)

Question 17

How do we manage severe persistent asthma? (prescribing)

Answer 17

SABA

+

medium dose ICS + LABA
or
high dose ICS + LABA
or
addition of leukotriene modifier, LAMA, or biologic drug

Question 18

Asthma

What are the class of some biologic drugs that might be used in severe persistent asthma?

Answer 18

anti-IgE
IL-4
IL-5

Question 19

Asthma

How do we manage asthma (non-prescribing)?

Answer 19

• prevention
• routine monitoring of pulmonary funtion
• review of medication
• patient education
• home monitoring of PEF

Question 20

Asthma

What investigation is used to diagnose occupational asthma?

Answer 20

Serial peak flow measurements

A peak flow diary can provide objective evidence in the diagnosis of occupational asthma.

Isocyanates (commonly found in spray painting) is thought to be the most frequent culprit for occupational asthma, but a wide variety of other substances (e.g. flour) have been implicated.

Question 21

Asthma

What is Fractional exhaled nitric oxide?

Answer 21

This is the first-line investigation for asthma recommended by NICE, along with spirometry.

Nitric oxide is a biomarker for asthma which provides an indication of the level of inflammation in the lungs.