Condition- Asthma Flashcards
Define Asthma
Chronic inflammatory airway disease characterised by intermittent airway obstruction and hyper-reactivity
What type of hypersensitivity reaction is asthma? Which WBCs and inflammatory mediators are involved?
- Type 1 hypersensitivity reaction
- WBCs: Th2 cells and eosinophils
- Inflammatory mediators: IL-4,5 and 13 and TNF-a
What three factors contribute to airway narrowing?
- Airway Inflammation
- Airway Hyper-reactivity which leads to Smooth muscle contraction
- Increased mucus production
What are the Genetic risk factors for developing asthma?
- Positive FHx
- Atopic History (childhood eczema, allergic dermatitis)
What are the environmental risk factors for developing asthma?
- ALLERGENS: pollen, dust mites, pets, cigarette smoke
- VIRAL: rhinovirus, RSV, human metapneumovirus and influenza
- BACTERIAL: Mycoplasma pneumoniae or Chlamydia pneumoniae
- Aspergillus spores
- OCCUPATIONAL: bakers, farmers, carpenters, chemical producers
What are the presenting symptoms of asthma?
- productive/ non-productive cough
- wheeze
- intermittent SOB
- chest tightness
- sleep disturbance
- worse on waking up
- other atopic diseases (allergic rhinitis, urticaria, eczema)
- (may also have acid reflux)
- (may have previous hospitalisations if severe)
State some precipitating factors for Asthma (9)
- Allergens: dust mites, pets, pollen
- Cigarette smoking
- Pollution
- Cold air
- Viral/ bacterial infections: common cold
- Drugs: B-Blockers, NSAIDs
- Exercise (quantify exercise tolerance)
- Emotions
- Occupational: (ask if its better during weekends)
What are the signs of asthma on physical examination?
- Tachypnoea+ Dyspnoea
- Use of accessory muscles
- Polyphonic high pitched expiratory wheeze- but silent in severe exacerbations
- Hyper-resonant percussion note
- Hyperinflated chest
- Reduced air entry-nasal congestion (if nasal polyposis)
- Prolonged expiratory phase
What are the appropriate investigations to identify acute excaerbations of asthma?
- Peak expiratory flow rate (PEFR)
- Pulse oximetry
- Short-acting bronchodilator trial
- ABG: normal or slightly low PaO2 and low PaCO2 (hyperventilation) – if PaCO2 raised, transfer to HDU for ventilation for resp failure
- CXR
What would you see on a CXR of someone with asthma? Why?
Hyper-inflation- asthma is an obstructive disease so air becomes trapped in the alveoli
What are the appropriate investigations to identify chronic asthma in adults?
- FeNO: Fraction exhaled Nitric Oxide
- Spirometry: FEV1/FVC ratio
- Bronchodilator Reversibility Pre- and post-bronchodilator spirometry – shows obstructive defect
- Peak expiratory flow variability >20% diurnal variation with AM dip at least 3/7 days a week for several weeks
What would be the positive results of the following investigations to identify asthma?
- Spirometry:
- Brochodilator Reversibilty:
- PEFR variabilty:
- CXR:
- Spirometry: FEV1/FVC ratio <70% than normal
- Brochodilator Reversibilty: >12% +200ml volume improvement in FEV1 following b2-agonist or steroid trial
- PEFR variability: diurnal variation with a dip in the morning (>20% variation)
- CXR: hyperinflation
Patient presents to the GP for the first time with symptoms of asthma around two times a week especilally during exercise. How would you manage this?
Inhaled SABA (salbutamol) as reliever therapy
If a patient has been given medication to asthma, what indicates that the patient’s asthma is inadequately controlled and that they must move up a step?
- Symptoms at presentation indicate the need for maintenance therapy (symtpoms >3/week or cauing waking at night)
- If asthma uncontrolled with SABA alone
A patient is on step 1 treatment for asthma and is using their salbutamol inhaler as required (2 puffs of their inhaler i.e. 200mcg during exacerbations). But he has recently been using his inhaler nearly four times a week and has noticed that his athma is interfering with daily tasks such as shopping. What would be the next step of treatment?
STEP 2: SABA + low-dose inhaled corticosteroid (fluticasone, budesonide, flunisolide)
Go through the stepwise management of chronic asthma
STEP 1: SABA
STEP 2: Low-dose ICS + SABA (if >3 episodes/week or if waking at night)
STEP 3: low-dose ICS + LTRA + SABA
STEP 4: low-dose ICS + LABA + SABA +/- LTRA
STEP 5: low-dose ICS + LABA (in MART regimen) + SABA +/- LTRA
STEP 6: moderate-dose ICS + LABA (as MART or fixed dose) + SABA +/- LTRA
STEP 7a: high-dose ICS + fixed dose LABA + SABA +/- LTRA
or STEP 7b: moderate-dose ICS + trial (theophylline or LAMA) + SABA
STEP 8: add ORAL PREDNISALONE (the emergency pack)
What advice could be given to patients with poorly controlled asthma?
- They could be taught proper inhaler technique
- Could teach the importance of PEFR monitoring (twice a day)
- Smoking cessation
What three questions does the RCP recommend you ask to gauge the severity of the person’s asthma?
In the last month:
- have you had difficulty sleeping because of your asthma symptoms (including cough)? (662P)
- have you had your usual asthma symptoms during the day (cough, wheeze, chest tightness, or breathlessness)? (662Q)
- has your asthma interfered with your usual activities (e.g. housework, work/school, etc)?
State a complication of using an ICS inhaler- what can pts do to prevent this?
Candidiasis
Wash out mouth after use
What is an acute asthma exacerbation
Acute worsenig of asthma symptoms.
Asthma exacerbation can be categorised into moderate acute, severe acute, life-threatening acute and near fatal acute. What is the criteria for a moderate acute attack?
- PEFR> 50-75%
Asthma exacerbation can be categorised into moderate acute, severe acute, life-threatening acute and near fatal acute. What is the criteria for a severe acute attack?
- PEFR: 33-50% PB
- RR: >25 breaths per mintue
- HR: >110bpm
- Unable to COMPLETE SENTENCES
Asthma exacerbation can be categorised into moderate acute, severe acute, life-threatening acute and near fatal acute. What is the criteria for a life-threatening acute attack?
- PEFR: < 33%
- SpO2: < 92%
- PaO2: <8kPa
- All of the signs for moderate
- Clinical Signs: Silent chest, cyanosis, exhaustion, use of acccessory breathing muscles, arrhythmia, hypotension
Asthma exacerbation can be categorised into moderate acute, severe acute, life-threatening acute and near fatal acute. What is the criteria for a near fatal attack?
- Signs of life-threatening attack
-
+ HIGH PaCO2
- Indicates decreasing respiratory drive because of exhaustion
- Hyperventialtion during an attack should mean CO2 is being blown off so it should be low.
- If exhaustion sets in patient’s don’t breathe as much and CO2 accumulates
Which investigations could you perform on a patient with a suspected asthma exacerbation?
- PEFR, Pulse Ox
- ABG- should be low PaO2 and low PaCO2
- CXR- to rule out other causes
- Bloods: high WCC (infective), check FBC, high ESR,
- Sputum Culture
Describe the steps of managing an asthma exacerbation…
- Take Metered Dose inhaler of Salbutamol (all)
- Oral Prednisalone 1 tablet/day for 5 days/ recovery (all)
- Hospital admission if this doesn’t work
- High Flow O2 via venturi mask/ nasal cannulae (severe-life-threatening)
- Add Nebulised Ipratropium Bromide to SABA
- IV Magnesium Sulfate (need ECG to monitor for arrhthmias because of electrolyte imbalance) (life threatening)
- IV Aminophylline (life threatening/ fatal)
- Intubation and ventilation in ICU
Note: need to monitor PaCO2
