Clinical features of asthma

Question 1

Define asthma

Answer 1

Disease characterised by an increased responsiveness of the trachea and bronchi to various stimuli and manifested by a widespread narrowing of airways that changes in severity either spontaneously or as a result of therapy

Question 2

What are the 3 main characteristics of asthma?

Answer 2

Airflow limitation
Airway hyperresponsiveness to stimuli
Inflammation of the bronchi

Question 3

What causes the narrowing of airways in asthma?

Answer 3

Inflammation and build up of cellular debris and mucus in the airways. In chronic asthma, there is airway remodelling.

Question 4

Describe the prevalence of asthma in both children and adults

Answer 4

Children: 10-15%, M>F
Adults: 5-10%, F>M

Question 5

List some risk factors for asthma

Answer 5

Genetics - atopy
Occupation
Smoking - maternal + grandmother effect

Question 6

What is atopy?

Answer 6

Atopy is the increased tendency to IgE response to allergens

Question 7

List some possible risk factors for asthma

Answer 7

Obesity
Diet
Reduced exposure to microbes
Indoor pollution: chemical household products

Question 8

What environmental agents are linked to atopy and asthma?

Answer 8

House dust mite
Cats
Grass pollen

Question 9

What are the symptoms of asthma?

Answer 9

Wheeze on expiration
SOB
Chest tightness
Sudden dry cough
Sputum occasionally 
Can be worse at night

Question 10

Describe some examples of evidence of variable symptoms in asthma

Answer 10

Triggers - cold, smoke, perfume, pets
Daily variation - nocturnal/early morning
Weekly variation - when at work/home only
Annual variation - seasonal allergens

Question 11

What drugs can increase the severity of asthma?

Answer 11

Aspirin
Beta blockers
NSAIDs

Question 12

What clinical signs would you seen on examination in asthma patients?

Answer 12

Breathless on exertion
Reversibility of symptoms with treatment
Hyperexpanded chest
Polyphonic wheezes on expiration

Question 13

What clinical signs on examination would rule out asthma?

Answer 13

Clubbing
Cervical lymphadenopathy
Stridor
Asymmetrical expansion
Dull percussion - effusion
Crepitations

Question 14

What investigations would you carry out for asthma?

Answer 14

Full pulmonary function tests
Spirometry
Carbon monoxide transfer
Reversibility to bronchodilator
Reversibility to corticosteroids
Variability in various peak flow readings
CXR - exclude other DD, hyperinflation
Skin prick tests
Total and specific IgE
FBC - eosinophilia in atopy

Question 15

When is it deemed that reversibility of airflow following the use o bronchodilators is significant enough to diagnose asthma?

Answer 15

FEV1 >200ML

FEV1 >15% baseline

Question 16

How do you diagnose occupational asthma?

Answer 16

Serial peak flow readings
- every 2 hrs for 5 days
- 2 pairs of exposed vs unexposed periods
Antibodies
Bronchial challenge using nebulised agent

Question 17

List two specialist investigations for asthma

Answer 17

Airway responsive to metacholine/histamine

Exhaled nitric oxide (higher in asthma)

Question 18

Describe the effect of metacholine on the airways

Answer 18

When inhaled, it causes the airways to spasm and narrow if asthma is present

Question 19

How do you assess severe asthma?

Answer 19

Ability to speak
HR 
RR
PEF
O2 sat/arterial blood gases

Question 20

Describe moderate asthma

Answer 20

Can speak in full sentence
HR <110
RR <25
PEF 50-75% predicted/best
SaO2 >92%
PaO2 >8kPa

Question 21

Describe severe asthma

Answer 21

Cant speak in full sentence
HR >110
RR >25
PEF 33-50% predicted/best
SaO2 > 92%
PaO2 > 8kPa

No effect on O2 yet

Question 22

Describe life threatening asthma

Answer 22

Grunting, impaired consciousness 
HR >130
RR >25, hypoventilating
PEF <33% predicted/best
SaO2 < 92%
PaO2 < 8kPa
Cyanosis, PaCO2 normal but can rise

Question 23

What are the main differences in asthma in children?

Answer 23

Prevalence and gender : M>F
Severe asthma
Occupational asthma uncommon

Question 24

What % of UK children are thought to have asthma?

Answer 24

10-15%, 5% on steroids

Question 25

What are the multiple hits that lead to asthma development?

Answer 25

Genetic susceptibility
Inherently abnormal lungs
Early onset atopy
Later exposure to allergens
Exercise
Smoking

Question 26

Describe the symptoms of childhood asthma

Answer 26

Wheeze!
Dry cough
SOB at rest
Atopic disease
Family history of asthma
Sinusoidal
Multiple known triggers
Responds to treatment

Question 27

What are some triggers of asthma?

Answer 27

URTIs
Exercise
Allergens
Cold air
Emotion/menstruation

Question 28

What conditions suggest atopic disease?

Answer 28

Asthma
Eczema
Hayfever
Food allergies

Question 29

Describe diagnosis of asthma in children

Answer 29

Response to ICS for 2 months

Question 30

What are some differential diagnoses for asthma?

Answer 30

Foreign body
CF
Immune deficiency
Primary ciliary dyskinesia
Aspiration
Gastro-oesophageal reflux
Trachea-bronchomalacia
Viral induced wheeze

Question 31

What should you treat infrequent viral induced wheeze with?

Answer 31

Salbutamol

NO steroids

Question 32

Give some examples of causes of isolated coughs

Answer 32

Pertussis
Bronchitis
Habitual cough
Tracheomalacia

Question 33

Describe bronchitis

Answer 33

Common, loose rattly wet cough
Noisy breathing
Chest free of crepitations
Child usually feels well, self-limiting

Question 34

Describe pertussis

Answer 34

Whooping cough
Severe coughing fits, petechiae
Vaccination reduces risk and severity