Asthma

In patients of all ages with respiratory symptoms (acute, chronic, recurrent):
1. Include asthma in the differential diagnosis.
2. Confirm the diagnosis of asthma by appropriate use of:
  - history.
  - physical examination.
  - spirometry.
In a child with acute respiratory distress, distinguish asthma or bronchiolitis from croup and foreign body aspiration by taking an appropriate history and doing a physical examination.
In a known asthmatic, presenting either because of an acute exacerbation or for ongoing care, objectively determine the severity of the condition (e.g., with history, including the pattern of medication use), physical examination, spirometry). Do not underestimate severity.
In a known asthmatic with an acute exacerbation:
1. Treat the acute episode (e.g., use beta-agonists repeatedly and early steroids, and avoid under-treatment).
2. Rule out co-morbid disease (e.g., complications, congestive heart failure, chronic obstructive pulmonary disease).
3. Determine the need for hospitalization or discharge (basing the decision on the risk of recurrence or complications, and on the patient’s expectations and resources).
For the ongoing (chronic) treatment of an asthmatic, propose a stepwise management plan including:

- self-monitoring.
- self-adjustment of medication.
- when to consult back.

For a known asthmatic patient, who has ongoing or recurrent symptoms:
1. Assess severity and compliance with medication regimens.
2. Recommend lifestyle adjustments (e.g., avoiding irritants, triggers) that may result in less recurrence and better control.

Diagnosis

History of variable respiratory symptoms
- Generally more than one respiratory symptom (wheeze, dyspnea, cough, chest tightness)
  - Isolated cough in adults is seldom due to asthma
- Worse at night or early morning (on waking)
- Symptoms vary over time and in intensity
- Triggered by endogenous/exogenous stimuli (exercise, laughter, allergens, changes in weather, irritants - eg. car fumes, viral infections)
Documented airflow limitation: Reduced FEV1/FVC (<0.75-0.8 in adults and <0.9 for children) AND variable expiratory airflow limitation:
- Post-bronchodilator reversiblity increase in FEV1 >12% (minimum of 200mL in adults)
- Excessive variability in twice-daily (diurnal) PEF over 2 weeks (adults >10%, children >13% daily diurnal variability)
- Significant increase in lung function after 4 weeks of anti-inflammatory treatment (adults FEV1 >12% and >200mL increase from baseline)
- Positive exercise challenge test (adults decrease FEV1 >10% and >200mL or in children decrease FEV1>12% predicted or PEF >15%)
- Positive bronchial challenge test/methacholine (Fall FEV1≥20% or ≥15% with standard hyperventilation, hypertonic saline or mannitol challenge)
- Excessive variation in lung function between visits *less reliable (FEV1>12% and 200mL in adults)

Diagnosis in Preschoolers (one to five years of age)

Documentation of airflow obstruction (eg. wheezing or other symptom)
Documentation of reversibility of airflow obstruction (eg. improved with SABA ± oral corticosteroids)
No clinical evidence of an alternative diagnosis
- Some experts differentiate into "viral-induced wheezing" if only occurs in context of viral URIs

Wheezing in Infants/Children DDx

Asthma
GERD
Infectious
- Bronchiolitis (<2yo, wheezing/crackles, increased respiratory effort)
- Pneumonia
- Viral-induced wheezer (recurrent viral-triggered wheezing, history of asthma, eczema, atopy)
Foreign body aspiration
Cystic fibrosis
Tracheobronchial anomalies (vascular rings)
Mediastinal mass
Congenital heart disease / Heart failure (hepatomegaly, poor weight gain)

Asthma Management

Asthma control
- Symptom Control
  - Daytime > 2/week
  - Night-time waking due to asthma
  - Reliever use >2/week
  - Activity limitation due to asthma
- Future risk of adverse outcomes (independent of symptom control)
  - History of ≥ 1 exacerbation in previous year
  - Poor adherence
  - Incorrect inhaler technique
  - Low lung function
    - Measure lung function at 0, 3-6 months, then periodically
  - Smoking
  - Blood eosinophilia
Treatment issues
- Technique, adherence, side-effects
Patient education
- Encourage adherence with controller medication (even if symptoms infrequent)
- Comorbidities (rhinitis, sinusitis, GERD, obesity, OSA, mood)
- Smoking cessation
- Controlling environmental factors (triggers)
- Asthma action plan

Pharmacological therapy

GINA recommends adding an ICS-formeterol (eg. Symbicort) even in mild intermittent asthma in 12+ year old, as adding any ICS significantly reduces the risk of severe exacerbations (NNT 8 to prevent one severe exacerbation per year) and decline in lung function at a population level
- No studies of "as needed" ICS-formoterol in children
- An alternative first-step is ICS + SABA, but there are concerns of poor adherence to the ICS

ICS + LABA PRN (reliever) in 12+ years old
- Symbicort Turbuhaler (budesonide/formoterol) 200/6 mcg 1 inh PRN (max 6 inh/time, max 8 inh/day)
ICS maintenance + SABA PRN (reliever)
- Flovent HFA (fluticasone) 50, 125, 250mcg 1 inh BID
- Pulmicort Turbuhaler (budesonide) 100, 200, 400mcg 1 inh BID
- Ciclesonide (Alvesco) 400 mcg once daily
- Starting doses: Flovent 100-250mcg, Pulmicort 200-400mcg
ICS + LABA maintenance and PRN in 12+ years old
- Symbicort Turbuhaler (budesonide/formoterol)100/6, 200/6 mcg 1-2 inh BID (max total including maintenance and reliever 72 mcg formoterol/24h)
  - Reliever 200/6 mcg 1 inh PRN (max 6 inh/time)
- Advair Diskus (fluticasone/salmeterol) 100/50, 250/50, 500/50mcg 1inh BID
Refer for add-on treatment (LAMA Tiotropium, anti-IgE, anti-IL5, oral steroids, Bronchial thermoplasty, SC/SLIT)

LTRA are less effective than ICS
- Consider if unable/unwilling to use ICS or in concomitant allergic rhinitis
- Singulair (Montelukast) 5, 10mg 1 tab PO PRN
In <5yo, use MDI with spacer and face mask or nebulizer, and dose-adjust

Recommendations for initial controller therapy

If symptoms <2/month and no risk factors
- Consider no controller
If symptoms >2/month or risk factors
- Consider Low-dose ICS
If symptoms >2/week
- Low-dose ICS
Asthma most days or waking due to asthma ≥1/week
- Medium/high-dose ICS or Low dose ICS/LABA
Severely uncontrolled asthma or acute exacerbation
- Short course oral corticosteroids AND High-dose ICS or Moderate-dose ICS/LABA

Follow-up

Ideally 1-3 months after starting treatment, and q3-12 months after
- Step-up vs. Step-down
Patient Education
- Smoking cessation
- Healthy diet
- Weight reduction
- Breathing exercises
- Dealing with emotional stress
- Swimming in young people with asthma
- Vaccinations (influenza)
- Avoid indoor/outdoor allergens
- Avoid occupational exposures/allergens
- Caution with medications that could worsen asthma (NSAIDs, BB)
- Consider vaccinations (no good evidence)
Consider referral if
- Difficult confirming diagnosis
- Occupational asthma
- Uncontrolled asthma
- Risk factors for asthma-related death (ICU admission, anaphylaxis or confirmed food allergy)
- Treatment side effects

Exacerbation

Self-Management (Action Plan)

Early intervention in worsening asthma is key

Increase reliever frequency
Increase usual controller
- Quadruple ICS or Quadruple maintenance ICS/formoterol (max formoterol 72mcg/day)
Severe exacerbation (PEF <60%) or not improving after 48h
- Oral corticosteroids and contact doctor
  - Prednisolone 1mg/kg/day (40-50mg)

Hospital Management

Initial assessment
- ABC
- Life-threatening signs: Drowsiness, Confusion, Silent chest
  - Consult ICU, SABA, O2, prepare for intubation
Assess severity based on dyspnea, RR, HR, O2 sat, Lung function (or PRAM score)
- Mild-moderate
  - Talks in phrases, not agitated, Pulse 100-120, O2>90%
- Severe
  - Talks in words, agitated, RR>30/min, Accessory muscle use, Pulse >120bpm, O2 <90%
Oxygen (Target 93-95%)
SABA MDI with spacer 4-8 puffs or 5mg nebulizer q20 mins x 3 (for one hour)
- Then depending on severity, SABA 4-8 puffs q1-4 hours
  - No additional SABA if PEF >60-80% of predicted or personal best x4 hours
  - New spacer should be washed or primed with 20 puffs of salbutamol (because of static charge)
Early oral corticosteroids
- Methylprednisolone 40mg IV q12h (1-2mg/kg/day divided BID) until improved
- Prednisone 40-60mg daily (1-2mg/kg/day divided BID) x 3-5d for children, 5-7d for adults
- Dexamethasone 12-16mg daily (0.6mg/kg/day) for 1-2 doses
  - Consider longer 5-10 days depending on severity, taper glucocorticoids if >10d course
If severe
- Ipratropium bromide (Atrovent) MDI/spacer 4-8 inh or 0.5mg neb q20 mins then PRN q1-4h
- Consider MgSO4 2g (25-75mg/kg/dose) IV over 20 minutes
- Transfer to acute care facility
Measure lung function after one hour of treatment
- PEF<60% of predicted or best, or clinically not improved -> SEVERE
  - Continue treatment and reassess
- PEF 60-80% of predicted or best -> MODERATE
  - Consider Discharge
Discharge if no SABA x4h, PEF >60-80% of best or predicted, O2 >94% on RA
- Reduce reliever to as needed
- Start controller or step-up controller for 2-4 weeks
- Continue steroids if started, eg. Prednisone 30-50mg (or 1-2mg/kg/day) PO x 5 days
- Review action plan (and modify if needed)
- Early follow-up within 1 week