Asthma Flashcards
Etiology of Asthma
Chronic airway inflammation (bronchoconstriction), hypersecretion of mucus, and remodeling leading to airway thickening
Risk factors and things that exacerbate asthma?
Risk factors:
- Genetic (allergic conditions like AR, AD)
- Obesity
- Allergens, Air pollution, Smoke
- Respiratory infection
Exacerbate asthma:
- Exercise, hyperventilation
- Allergens
- Respiratory infections
- GERD
- Drugs (B-blockers, NSAID, ACEi)
- Weather changes, air pollution
- Food and additives
Clinical presentation and red flags of asthma:
Chest tightness, shortness of breath, cough, wheezing
- Often worse at night or in early morning
- Vary over time and in intensity
- Worsened by exercise, virus, allergens, change in weather, smoke, strong smells, etc.
Red flags:
Talk in words, sits hunched forward, agitated, accessory muscles used to breath, drowsiness, confusion, silent chest
How is asthma diagnosed?
History of characteristic symptoms (SOB, wheezing, chest tightness, cough) and Evidence of variable airflow limitation (lower FEV1 / FVC ratio)
- Normal FEV1 / FVC ratio >0.75-0.8 in adults; >0.90 in children
- Excessive bronchodilator reversibility (Adult: increase in FEV1 >12% and >200ml; Children increase >12% predicted)
- Excessive diurnal variability from 1-2 weeks’ 2x daily PEF monitoring (Adult avg variability >10%; Children avg variability >13%)
- Significant increase in FEV1 by >12% and >200ml (or PEF by >20%) from baseline after 4 weeks of controller treatment in adults
FEV1, FVC and PEF definitions
FEV1 (Forced Expiratory Volume of air exhaled in 1s after full inspiration): “Speed of exhalation”
FVC (Forced Vital Capacity): Total volume expired forcefully after full inspiration; “Whether air is trapped”
PEF (Peak Expiratory Flow): Self-administered objective measure of expiratory airflow limitation, measured by peak flow meter
Asthma Control Test (ACT) scoring, what is the time period assessed and how often?
Range from 5 to 25 (5 domains, score 1-5)
20-25 = well-controlled
16-19 = not well-controlled
5-15 = very poorly controlled
MCID is 3 points
Assess symptom control over the last 4 weeks, as well as future risk of adverse outcomes including low lung function.
Every 3-6 months periodically, 1-2 years after that.
Risk factors for Asthma Exacerbation?
- History of >= 1 exacerbation in the previous year
- Poor adherence
- Incorrect inhaler use
- High SABA use
Preferred Track (ICS-Formoterol) in adults & adolescents >=12yo
Step 1-2: PRN low dose ICS-Formoterol
Step 3: Low dose maintenance ICS-Formoterol
Step 4: Medium dose ICS-Formoterol
Step 5: Add on LAMA. Refer for phenotypic assessment ± biologic therapy. Consider high-dose ICS-formoterol
With ICS-Formoterol reliever.
Alternate track for adults and adolescents >= 12yo
Step 1: ICS whenever SABA is taken
Step 2: Low dose maintenance ICS
Step 3: Low dose maintenance ICS-LABA
Step 4: Medium/high dose ICS-LABA
Step 5: Add on LAMA. Refer for phenotypic assessment ± biologic therapy. Consider high-dose ICS-LABA
With PRN SABA as reliever
Symptoms for initial step
Step 1 (Alternate): Sx less than twice a month
Step 1-2 (Preferred track & 2 for alternate): Sx < 4-5 days a week
Step 3 (both): Sx most days, or waking with asthma once a week or more
Step 4 (both): Daily symptoms, or waking with asthma once a week or more, and low lung function
Short course OCS can also be used when presenting with severely uncontrolled asthma
Inhaled Corticosteroids MOA, Onset, Peak effect and Side effects?
MOA: Controls rate of protein synthesis of inflammatory cells, prevents or control inflammation
Onset & peak: 24 hours, peak in 1-2 weeks, full benefit may take 3-4 months or longer
SE: Throat irritation, hoarse voice, oral thrush, bruising elderly, [Long-term] Glaucoma, osteoporosis, respiratory infection
Frequency of monitoring?
Should be reviewed every 1-3 months after starting and every 3-12 months thereafter.
Review 1 week after an exacerbation.
How to step up and step down therapy?
Step-up:
- Day-to-day adjustment of ICS-Formoterol
- Short-term step-up (for 1-2w) e.g. during viral infection. May be in WAP or by HCP
- Sustained step-up (at least 2-3m)
Step-down:
- Once good asthma control maintained for 2-3 months and lung function reached a plateau
To find minimum effective treatment
SABA and LABA used in Asthma, MOA + SEs?
SABA: Salbutamol, Terbutaline
LABA: Formoterol, Salmeterol, Vilanterol
MOA: Relaxes bronchial smooth muscle by action on beta-2 receptors (agonist)
SEs: Fine tremors, muscle cramps, hypokalemia, hyperglycemia, palpitations, tachycardia
LAMA used in Asthma, MOA + SEs?
Tiotropium bromide, Umeclidinium
MOA: Inhibit M3-receptor mediated bronchoconstriction, reduce bronchospasm, mucus secretion, inflammation and airway smooth muscle hyperplasia induced by vagal nerves
SE: Dry mouth, constipation, urinary retention, cough/throat irritation, blurred vision, tachycardia
Other controllers (non-inhaler)
- Leukotriene-receptor antagonist (LTRA) e.g. Montelukast
- Theophylline
- House dust mite Sublingual Immunotherapy (HDM SLIT)
- Azithromycin
- Biologics
How to prevent exercise-induced bronchospasm
SABA or ICS-Formoterol 5-20mins before exercise
Mild or Moderate asthma exacerbation vs. Severe
Mild/Moderate = Talk in phrases, prefers sitting to lying, not agitated, accessory muscles not used, pulse rate 100-120bpm, O2 90-95%, PEF >50% predicted or best
Severe = Talk in words, sits hunched forward, agitated, accessory muscles used, respiratory rate >30/min, pulse rate >120bpm, O2 <90%, PEF ≤50% predicted or best
Recommended treatment for mild/mod exacerbation vs. Severe exacerbation
Mild/Mod = SABA, consider Ipratropium bromide, maintain O2 93-95% (children 94-98%), OCS
Severe = SABA, Ipratropium bromide, O2 93-95% (children 94-98%), Oral or IV CS, consider IV magnesium, consider high dose ICS
Assess clinical progress and measure lung function in 1 hour.
FEV1 or PEF 60-80% & Sx improved, consider discharge planning.
FEV1 or PEF <60% or lack of response, continue treatment as above and reassess frequently
OCS dosing and duration of therapy for exacerbation?
Adults: Prednisolone 40-50mg/day for 5-7 days
Children: Prednisolone 1-2mg/kg/day, max 40mg/day for 3-5 days
When to follow up after exacerbation?
Arrange for follow up within 2-7 days
Montelukast adult & children dose, and side effects
Adults: 10mg OD (for asthma & AR)
≥15 years: 10mg OD in the evening
6-14yo: 5mg OD
12m-5y: 4mg OD
Side effects:
- Sore throat, cough, cold
- Headache, dizziness, feeling tired
- Stomach pain, nausea, diarrhoea
Rare SEs:
- Mood and behaviour changes (nightmares, abnormal dreams, trouble sleeping, feeling irritated/restless/anxious)
- Pins and needles / numbness in arms or legs
- Worsening lung issues
Administration for Montelukast 4mg granules?
4mg oral granules:
- Consume within 15mins of opening sachet
- Can be mixed with a spoonful of room temperature food (applesauce, mashed carrots, milk, porridge)
- Alternatively, can feed directly into child’s mouth
- May drink other room temp liquids after swallowing granules OR can also mix with room temp water in a spoon and swallow immediately
- Granules will not dissolve in liquids above. Do not attempt to dissolve or crush granules
Administration for Montelukast 5mg chewable tablets?
Chew well before swallowing
