Asthma Flashcards
Describe asthma pathogenesis
Bronchi inflammation and reversible obstruction
1) bronchial muscle contraction (triggers)
2) mucosal swelling/inflammation(mast cell/ basophil degranulation : inflammatory mediators)
3) increased mucus
What Is asthma
Inflammation of bronchi (small tubes: carry air and out of the lungs) makes them more sensitive than normal on contact with a “trigger”.
Recurrent Sx: coughing wheezing, chest tightness, breathlessness (Severity varies from person to person.)
Common long-term condition
Occurs at any age including young children and elderly people
Controlled well most people, some may have persistent problems.
Who is affected by asthma
- 4 million people receive treatment for asthma in the UK
- 1/12 adults (Women>men)
- 1/11 children
- 1/5 homes has somebody living with asthma
What is an “asthma trigger”
A trigger irritates the lungs, making them narrower, the muscles tighter, and an increase in sticky mucus
precipitants/triggers:
- environmental :cold air, allergens (mould/pollen/fur from pets/dustmites from carpet), occupation (isocyanates: spray paint, flour, latex, wood/metal fumes
- infection
- drugs(NSAIDS: aspirin, ibuprofen; beta blockers)
- sulphites: jam, fruit juice, wine; food allergies
- exercise tolerance
- emotion (stress)
The reason why some people develop asthma is not fully understood.
List some signs of asthma
- tachapnoea, audible wheeze
- hyperinflated chest
- percussion: hyperresonant
- auscultation: diminished breath sounds (low air entry), polyphonic wheeze
State some statistics/trends about asthma prevalence
Common long-term condition
Occurs at any age including young children and elderly people
List some symptoms of asthma
- wheeze (whistling sound on breathing), SOB, cough
- tight chest (“band tightening around chest”)
Worse:
- night/early morning
- trigger: exercise, allergen
List signs of a severe asthma attack
- Blue inhaler: not helping symptoms as usual
- severe/constant: wheeze, cough, chest tightness ; breathlessness (cant eat/speak/sleep); faster breathing; cyanosis (lips/fingers)
- rapid heartbeat
- drowsy, exhausted, dizzy
Call 999
List some signs of severe asthma attack
Severe attack:
inability to complete sentences
tachycardic >110 bpm, tachapnoeic >25/min
Low PEF
List some signs of life threatening attack
Auscultation: Silent chest, feeble resp effort
Inspection: Cyanosis
Other: Bradycardia, exhaustion, low PEF, confusion
List some differentials
Pulmonary oedema (“cardiac asthma”); pneumothorax, PE
Bronchiectasis, obliterative bronchiolitis (elderly)
COPD: often concommitant
Obstruction: Large airway (fb, tumour); SVC obstruction (wheeze/dyspnoea constant not episodic)
What is an “asthma attack”/”exacerbation”
worsening of asthma symptoms: Gradual (days)/sudden
-inhaler may not work as well as normal
-Peak expiratory flow may drop
(Important to recognise attacks early and take appropriate action)
Severe/Life-threatening attacks unusual (may require hospital treatment)
What would you need to ask about in a history
1)symptoms: severity, time (diurnal variation: marked morning dipping of peak flow), frequency
2) precipitants/triggers:
- environmental :cold air, allergens (pollen/fur from pets/dustmites from carpet), occupation (painters, bakers, animal handlers, wood/metal workers, nurses)
- infection
- drugs(aspirin, NSAIDS, beta blockers)
- exercise tolerance
- emotion (stress)
3) other atopic disease: eczema, allergy, family hx
4) disturbed sleep (number of nights), days off work/school
4) acid reflux: assoc with asthma
What do you do if someone/child is having an asthma attack
1) contact GP/asthma clinic asap
2) consult asthma action plan
What are the causes of asthma
Not fully understood
1) environmental:
- hygiene hypothesis: modern hygiene (Chlorine in swimming pools)
- triggers/irritants: occupational
2) genetic: familial (asthma or other allergic/atopic conditions)
3) pregancy/birth
- mother smoked
- premature birth: requiring ventilation
- low birth weight (low growth in womb)
4) infection: childhood bronchiolitis
How would you diagnose asthma
1) Symptoms (Explore), pmhx (atopic conditions)
2) tests
- spirometry (assess lung function): compared with averages to show airway obstruction / “reversibility testing” (given inhaler to see if sx improve, allows differentiation from COPD)
- peak expiratory flow test (peak flow meter): keep diary of readings during day/at work to confirm diagnosis
3) advanced testing
- airway responsiveness: induce mild asthma with trigger (to measure how airways react on trigger exposure). Inhale increasing amounts of exercise/medication and record FEV1
- airway inflammation: mucus sample, NO concentration on exhalation (high in inflammation)
4) allergy test: skin/ blood
What is spirometry
1) take a deep breath
2) exhale as fast as possible through a mouthpiece
3) detected by spirometer as FEV1 and FVC
4) repeat few times: accuracy
5) compare measurements against averages for age/sex/ht or obstruction
6) possible “reversibility testing” with exercise or drugs
2 measurements made:
-FEV1: volume of air exhaled/1st second of expiration
-FVC: total volume of air breathed out
(F=forced expiration)
What is PEF
1) Small hand held device “peak flow meter”
2) breathe max air possibke out of lungs in 1 breath
3) measure
4) takes practice: best of 2-3 readings taken
5) record results at home or work (several times a day to identify asthma)
How is asthma treated
There is no cure. Treatment is based on relieving symptoms and preventing future symptoms/attacks.
(asthma symptoms are usually controllable and reversible with treatment.)
1) lifestyle: identify triggers,asthma action plan(recognise attacks, symptoms, treatment)
2)medications: inhaler (pressurised cannister or powder)
+-spacer
What is atopy/atopic syndrome
Tendency to be hyperallergic
1) atopic dermatitis: eczema
2) allergic rhinitis: hay fever
3) allergic asthma
How do inhalers work
Medication delivered directly to the lungs: effective
Needs GP training: different types
- pressurised cannisters (like deodrant): press inhaler while breathing in vapours
- dry powder: puncture capsule and inhale powder (harder as needs forceful inspiration to reach lungs)
What are spacers
A spacer is a hollow plastic/metal container with 2 holes at either end (mouthpiece and inhaler)
Vapour from cannister slowly released into spacer: breathe in till lungs full then hold breath to allow dissipation
Advantages:
- Help cannisters work better: more efficient (more to lungs, better distribution in lungs, less wasted/SE in mouth)
- easier for children (spacer can be attached to face mask)
- reduced risk oral/throat thrush
