Asthma Flashcards
how does the WHO define asthma?
– Recurrent episodes
– Variability
– Reversibile airways inflammation
– Bronchial hyper-responsiveness to external
stimuli
what is the pathophysiology of the early phase of asthma?
- Initiation of inflammatory cascade (early phase) – IgE
antibodies released - IgE leads to activation of mast cells
- Activation of mast cells lead to release of
leukotrienes, cytokines, histamine smooth muscle
constriction and inflammation
what is the pathophysiology of the late phase asthma?
T-cells, macrophages, eosinophils recruit ->
inflammation and bronchoconstriction (late phase)
what are the main causes/ triggers of asthma?
– Genetic links - not absolute
– House dust mite
– Animal allergens- e.g. cats
– Pollens e.g. grass, trees
– Infections - particularly viral
– Occupational agents in workplace
– Drugs
– Passive / current smoking
how do you confirm diagnosis of high probability asthma?
– Six week treatment trial of inhaled corticosteroids and SABA
– Assess response objectively (done as part of SCA)
* Baseline needed
* Assess patient status using a validated symptom questionnaire
(asthma control questionnaire)
* Perform objective lung function tests (spirometry OR peak
expiratory flow)
Improvements in symptoms and objective tests following
treatment trials strongly indicate asthma. Lack of improvements
suggest alternative diagnosis
what would a normal patients spirometry reading show?
- High forced vital capacity (FVC)
- High forced expiratory volume in one second (FEV1)
what would an obstructive patients spirometry reading show?
- Low forced vital capacity (FVC)
- Low forced expiratory volume in one second (FEV1)
what increases the probability of asthma in spirometry?
– Obstructive: FEV1/FVC <0.7
– Positive result: improvement in FEV1 of ≥ 12% with an increase in volume of 200ml
– Improvement in FEV1 of ≥ 400ml – strongly suggests asthma
what is a peak flow?
- Provides estimate in variability of
airflow based on level of inflammation
in lungs – different to spirometry! - Measures force an individual can
breath out with
how does the peak flow meter work?
- Patients have a baseline that is normal
for them but there are expected values
based on height, weight, age.
– More inflammation on lungs –
lower scores compared to baseline
– Less inflammation on lungs –
higher / normal scores compared
to baseline - We look for variability in readings over
a 2 week period to gauge diagnosis /
control of asthma
how do you preform a peak flow meter?
– Deep breath in
– Hold breath for two seconds
– Rapidly breathe out
– Record value
– Do this three times morning and night and record the best from each
Repeat this twice daily for two weeks
* Take an average of all “best” readings from daytime and evening
* Take the highest and the lowest readings and calculate express
these as a percentage of the average. A 20% difference between
these values strongly suggests asthma
what is complete control defined as?
– No daytime symptoms
– No night time awakening due to asthma
– No need for rescue medication
– No asthma attacks
– No limitations on activity including exercise
– Normal lung function
– Minimal side-effects from medication
what is the BTS approach to asthma?
- Start at the level most appropriate to initial severity
– For most individuals this is SABA PRN for relief of
symptoms and ICS BD for prevention of symptoms - Overall aim: Achieve early control reduce risk of
acute attacks and hospitalisation - Maintain control by:
– Increasing treatment
– Decreasing treatment
what is the drug treatment available for asthma?
- Relievers
– Bronchodilators: relax smooth muscle in walls of airways
– Salbutamol, terbutaline – SABAs (short acting beta agonists) - Preventers
– anti inflammatory drugs which reduce inflammation in the airways e.g. corticosteroids, leukotriene receptor
antagonists
– Bronchodilators: long acting beta agonists to provide
longer lasting relaxation of smooth muscles
when should you step up therapies?
– Asthma attack in the last 2 years
– Using inhaled SAB2A 3 times per week
or more
– Symptomatic 3 times per week or more
– Waking 1 night per week
– Asthma affecting daily activities
when should you decrease therapy?
–When good control is established –
consider decreasing therapy
–ICS: stable patients, consider
reducing dose by 25 – 50% every 3
months
what are the important points relating to SABA?
– Little or no use is classified as GOOD asthma control.
– Regular use suggests possible poor control - we should be aiming to control symptoms with
preventer inhalers not rely on relievers to manage symptoms when present. Evidence
suggests over-reliance of SABA associated with increased mortality.
– If a MART regime initiated, no need for SABA (see later slides)
what are the important points relating to ICS?
– Should be prescribed at ALL stages of asthma management.
– Counselling essential on adherence and minimisation of side effect risk.
– Growth retardation - rare and mostly occurs in children up to 1 year old.
– Brand prescribing – beclomethasone bioavailability differences (Clenil versus QVAR)
– Potencies – BDP:BUD (1:1). FLU:BPD (1:0.5)
what ae the important points relating to LABA?
– Never to be prescribed without ICS – increased mortality
– Combination inhalers: Safety, adherence, no difference in efficacy
what are some examples of combination inhalers?
– Fostair (Formoterol / beclomethasone)
– DuoResp (formoterol / budesonide)
– Seretide, sirdupla, sereflo (salmeterol / fluticasone)
– Relvar (Vilanterol / fluticasone)
what is theophylline?
– Modified release
– Extensive hepatic metabolism and narrow therapeutic index (interactions)
* Inhibitors, inducers, smoking, heart failure
– Monitoring – 5 days after starting, 3 days after dose change taken 4-6 hours after
a dose (10-20mg/L target)
what is a MART regimes?
MART: Maintenance and Reliever Therapy
– Alternative approach to fixed dose initial add on therapy (LABA/ICS)
* ONE inhaler is used as both reliever (PRN use) and preventer (BD use)
what does a MART contain? what was ge reason for this?
MART regimes still contain a LABA and ICS but the LABA must be one which is rapid acting so that it can act as a reliever therapy. E.G. formoterol
what are the requirements to prescribe a MART regimen?
– 18+
– Continued poor control despite taking regular preventative therapies
– When one inhaler is preferred over separate preventer and reliever
what advice should you give to a patient on MART regime?
– A maintenance dose in the morning and evening should continually be
used
– If you have symptoms throughout the day, you can use extra puffs of
your inhaler (reliever doses).
– For example: Fostair 100/6mcg 1p BD. Use additional puffs PRN up to a
maximum of six extra doses per day (max 8 puffs per day)
What is the benefit of MART regimes?
– Keeps inflammation in airways to a minimum
– Gives ongoing relief of symptoms such as breathlessness or chest
tightness
– Acts quickly to manage symptoms and reduce risk of developing an
asthma attack and therefore reduces risk of hospital admission
– As patients use more extra reliever doses, the requirement will reduce
with time due to the extra anti-inflammatory effects of the ICS and
therefore provides longer term control of asthma
what are the common therapeutic problems with asthma?
- Under diagnosed
- Failing to avoid / reduce exposure to allergens
- Lack of patient knowledge about condition and its
management - When to start ICS Tx
- Taking ICS “prn”
- Missing signs of deteriorating asthma control
- Poor technique – poor compliance
what should you check on asthma review?
Adherence – is the patient taking their preventative
medications correctly
* Inhaler technique – are they using their inhalers properly
(can they SHOW you)
* Symptoms: Daytime, night time, activities
– SABA use as a result? >3x/week?
* Asthma control questionnaire
* Peak expiratory flow readings (variability)
* Triggers / smoking status
* Does the patient have a PAAP? (See later)
what are the different type of devices available?
- pMDI (standard or easi-breathe)
– Salbutamol evohaler, salbutamol breath-actuated
– Fostair evohaler (formoterol/beclomethasone), Seretide evohaler
(salmeterol/fluticasone)
- Soft mist (Respimat)
– Spiriva Respimat (tiotropium) - Dry powder inhalers:
– Turbohaler – Symbicort (formoterol/budesonide), Pulmicort (budesonide)
– Breath actuated – DuoResp (formoterol/budesonide)
– NEXThaler – Fostair (formoterol/beclomethasone)
– Accuhaler – Seretide (salmeterol/fluticasone)
– Ellipta – Incruse (umeclidinium)
– Breezehaler – Seebri (glycopyrrinium)
– Genuair – Eklira (aclidinium)
what is acute asthma?
– Deteriorating symptoms over hours/days
– Increasing breathlessness, wheezing, coughing, tightness
– Difficulty talking in sentences
– Tachycardia, tachypnoea
– Reduced PEFR
– Reduced oxygen saturations
how is moderate asthma classified?
spo2>92%
normal speech
RR <25
pulse<110
how is acute severe asthma classified?
spo2>92%
cant complete sentences
RR >25
pulse>110
how is life-threatening asthma classified?
spo2<92%
silent chest, cyanosis or poor respiratory effect
arrhythmia or hypo
exhaustion, alt consciousness
what supported management is there?
- Education
– Disease
– Symptom recognition + management (PAAP)
– Review
– Compliance/Inhaler technique
what are supported self-management? non-pharmacological?
- Non-pharmacological management
– Avoid known allergens and triggers - Difficult, expensive, time consuming
– Stop smoking, exposure to passive
smoking
– Breathing exercises
– Ideal body weight
