Asthma

Question 1

extrinsic asthma (allergic asthma)

Answer 1

atopy is the cardinal risk factor
triggered by environmental allergens: dust mites, domestic animals, mould spores

Question 2

intrinsic asthma (non-allergic asthma)

Answer 2

viral respiratory tract infections are a common stimuli
cold and heat
physical exertion
GORD
chronic sinusitis
some medications
stress
irritant induced occupational asthma

Question 3

clinical features that increase the probability of asthma

Answer 3

more than one of the following symptoms: wheeze, breathlessness, chest tightness or discomfort, cough—particularly if symptoms:

are worse at night and in the early morning
occur in response to exercise, allergen exposure or cold air
occur after taking aspirin or beta blockers
are recurrent

history of atopic disorder (eg allergic rhinitis, atopic dermatitis)

family history of asthma or atopic disorder

widespread wheeze heard on auscultation of the chest

improvement in symptoms or lung function in response to standard asthma therapy

otherwise unexplained low FEV1 or PEF (historical or serial readings)

otherwise unexplained peripheral blood eosinophilia

in children, presence of conditions associated with asthma (eg bronchopulmonary dysplasia, obstructive sleep apnoea, recurrent bronchiolitis)

Question 4

Lung function tests commonly used in the diagnosis of asthma

Answer 4

spirometry, peak expiratory flow monitoring and fractional exhaled nitric oxide (FeNO) measurements

Question 5

Spirometry findings that support a diagnosis of asthma

Answer 5

reversible airflow limitation—an increase in forced expiratory volume in 1 second (FEV1) of at least 200 mL and 12% from baseline 10 to 15 minutes after giving a short-acting beta2 agonist (SABA) (200 to 400 micrograms inhaled salbutamol or equivalent). A larger increase in FEV1 (eg more than 400 mL) in response to a SABA is strongly supportive of asthma

expiratory airflow limitation—reduced FEV1 to forced vital capacity (FVC) ratio (FEV1/FVC ratio).

Question 6

peak flow measurement is useful when

Answer 6

PEF measurements are particularly useful if taken over a 14-day period when the patient is both asymptomatic and symptomatic. Variation of greater than 20% between the two highest measurements and the two lowest measurements taken during this period supports the diagnosis of asthma. Always use the same peak flow meter for each measurement.

Question 7

step up therapy for asthma control

Answer 7

Question 8

step 1

Answer 8

as needed SABA alone eg.

1. salbutamol 200 micrograms by inhalation via pMDI with spacer, as required

OR

2. terbutaline 500 micrograms by inhalation via DPI, as required

Question 9

step 2

Answer 9

budesonide+formoterol 200+6 micrograms by inhalation via pMDI with spacer or via DPI, as required

OR

SABA as required + daily ICS eg. budesonide, fluticasone

Question 10

step 3

Answer 10

ICS–formoterol maintenance-and-reliever therapy (SMART), low dose

OR

Regular daily maintenance ICS–LABA combination (low dose) ,+ SABA reliever as needed

Always give ICS+LABA as a combination inhaler—LABA monotherapy increases the risk of exacerbations and asthma-related death.

Question 11

step 4

Answer 11

ICS–formoterol maintenance-and-reliever therapy, high dose

OR

Regular daily maintenance ICS–LABA combination (medium–high dose) [+ SABA reliever as needed]

Always give ICS+LABA as a combination inhaler—LABA monotherapy increases the risk of exacerbations and asthma-related death.

Question 12

step 5

Answer 12

add on specialised treatments eg. monoclonal antibodies

Question 13

good control

Answer 13

all of:
daytime symptoms on 2 or fewer days per week
need for SABA reliever on 2 or fewer days per week
no limitation of activities
no symptoms during night or on waking

Question 14

partial control

Answer 14

one or two of:
daytime symptoms on more than 2 days per week
need for SABA reliever on more than 2 days per week
any limitation of activities
any symptoms during night or on waking

Question 15

poor control

Answer 15

> 2 of:
daytime symptoms on more than 2 days per week
need for SABA reliever on more than 2 days per week
any limitation of activities
any symptoms during night or on waking

Question 16

drugs to avoid in asthma

Answer 16

drugs associated with asthma exacerbations (eg NSAIDs for patients with aspirin-exacerbated respiratory disease, beta blockers)

If a patient with asthma develops an indication for beta-blocker therapy (eg heart failure, myocardial infarction), start beta-blocker therapy at a low dose under supervision.

Question 17

what is thunderstorm asthma

Answer 17

In Australia, thunderstorm asthma is more prevalent in spring or early summer in regions with high levels of rye grass pollen, particularly New South Wales, South Australia and Victoria.

pollen grains are swept up into clouds as a storm develops
moisture in the clouds ruptures the pollen grains into smaller granules that are respirable into the lower airways and cause acute onset of asthma symptoms (in contrast to the larger pollen grains, which lodge in the upper airways and cause allergic rhinitis)
as the thunderstorm ‘breaks’, it brings the pollen granules to ground level