Asthma

Question 1

state the normal FEV1/FVC

Answer 1

70% of lung volume in first second.

Question 2

Describe the definition of asthma

Answer 2

Airflow obstruction due to narrowing of airways + worsened by inflammation ( increases mucous)

• chronic inflammatory disease that involves overreactive constriction of bronchial SM
• REVERSIBLE airflow limitiation

Question 3

State the risk factors for asthma - Genetic

Answer 3

• Inherited tendency to IgE response to allegens ( asthma, eczema, hayfever, food allergy
• genetic ( maternal atopy most influential 3x father)
• Genetic associations: (1)Immune response genes ( I-4, IL-5, IgE)
  (2) Airway genes; ADAM33

Question 4

State the proven risk factors for asthma

Answer 4

Genetic, occupation, smoking,

Question 5

State the possible risk factors for asthma

Answer 5

Obesity, diet, exposure, indoor/outdoor pollution, pets

Question 6

State risks for asthma - smoking

Answer 6

-Maternal smoking during pregnancy

Question 7

State possible risk factors for asthma - diet

Answer 7

FEV1 decreases: -decrease vitamin E, C, D, B-carotene

Increase wheeziness: -decreases vitamin E & C, fruit, margarine

Increase asthma:
-decreases selenium, fast food, margarine

Decreases wheeze & asthma:
-Increases oily fish consumption, butter

Question 8

State the possible risk factors - exposure

Answer 8

• Reduced exposure to microbes/microbrial products may cause asthma
• Children born on farms are less likely to develop asthma.
• possible exposure to endotoxins, glucans, extracapsular poysaccharide

Question 9

State the possible risk factors for asthma - indoor pollution

Answer 9

• chemical household products
• voltatile organic compounds, formaldehyde, fragrances.
• mothers using sprays during pregnancy more likely to have asthmatic children. Cleaners also have a high risk

Question 10

State the environmental allergens and atopy/asthma

Answer 10

House dust mite ( protease in droppings) found in pillows/bed
Cats, grass pollen(timothy grass)
-these exposures will increase the liklihood of sensitisation to local allergens

Question 11

Other causes of wheeze

Answer 11

-localised airway obstruction: inspiratory stridor tumour, foreign body

• Generaised airflow obstruction:
• asthma ( reversible AFO)
• COPD ( irreversibe AFO)
• Bronchiectasis
• Bronchiolitis
• Cystic fibrosis

Question 12

State the symptoms of asthma

Answer 12

• wheeze
• History
• shortness of breath (dysnoea), severity
• chest tightness ( pain)
• cough, paroxsyma(usually dry)
• sputum ( occasional)

Question 13

State the evidence of variable symptoms

Answer 13

Triggers: excercise, cold air, smoke, perfume, URTI’s, pets, tree, grass pollen, food, aspirin

Daily variation ( noctornu/morning)
Weekly variation ( occupation, better at weekends?)
Annual variation ( environmental allergens)

Question 14

Pathphysiology of asthma

Answer 14

• Type 1 hypersensitivity reaction
• IgE production when exposed to allergens
• IgE binds and activates mast cells, widespread airway narrowing + excess mucous production = airflow limitation

Question 15

What symptoms will dismiss the symptoms of asthma?

Answer 15

Finger clubbing, cervical lymphadenopathy, stridor, asymmetric expansion, dull percussion note ( lobar collapse/effusion)
-Crepitations ( bronchiectasis, CF, alveolitis, LVF)

Question 16

State investigations that must occur with an ‘asthmatic’ patient

Answer 16

Evidence of:
Airflow obstruction
-variability/reversibility of AFO

Question 17

What testing should occur if there is evidece of airflow obstruction?

Answer 17

Full pulmonary testing ( excludes COPD/emphysema)

-Lung volumes + CO gas transfer

Question 18

What will the effect of gas trapping in an asthmatic patient show in an asthmatic patient?

Answer 18

Lung volumes ( helium dilution)
Gas trapping: increase in residual volume
Increase in total lung capacity
RV/TLC< 30%

Question 19

CO2 gas transfer ( transfer of CO2 to Hb across alveoli ) in an asthmatic patient

Answer 19

TLCO=
KCO=
( no tissue destruction

Question 20

If there is reversibility to bronchodilator

Answer 20

Investigation of:
response to bronchodilator
-Baseline, 15 minutes post 400ug inhaled salbutamol
Baseline, 15 minutes post neb 2.5-5mg salbutamol

Interpretation: significant reversibility :FEV1>200ml & FEV1> 15% baseline

BUT
no bronchoconstriction= no reversibility
severe bronchoconstriction = no reversibility

Question 21

If obstructed and reversibility to oral corticosteroids

Answer 21

• differentiates COPD from asthma

Question 22

If norma spiromtry but variabiloity of airflow obstruction

Answer 22

Lung function may be normal, but look for variabiity in airflow obstruction.
Peak flow meter _+ chart, twice daily for 2 wks

Question 23

Airway responsiveness to methacholine/histamine

Answer 23

exchaled NO

Question 24

Usefu investigations- Chest X-ray, skin prick testing, tota + specific IgE, Full blood count

Answer 24

Chest X-Ray:
-Hyperinflated, hyperlucent
(no effusion, collapse, opacities, interstitial changes)

Skin prick testing:
-(atopic status)

Total and specific IgE: -(atopic status)

Full blood count:
-Eosinophilia (atopy)

Question 25

Assestment of acute severe asthma

Answer 25

• Ability to speak
• Heart rate
• Respiratory rate
• PEF ( peak flow)
• Oxygen saturation /
• Arterial blood gases

Question 26

Assestment of moderate asthma

Answer 26

Able to speak
HR <110bpm
RR <25/min

Question 27

Assestment of severe asthma

Answer 27

Unable to speak
HR >110bpm
RR >25/min

Question 28

Assestment of life threatening asthma

Answer 28

Grunting/ confusion/exhaustion
HR >130, or bradycardic/arrythmia/hypotension
RR>25/min
Cyanosis(blue)

Question 29

Near fatal asthma

Answer 29

Raised PaCO2

Question 30

Types of inhalers

Answer 30

• pMDI’s
• pmDI’s + spacer
• breath acuated pMDIs
• Dry powder inhalers
• nebulisers