Asthma – Canadian Thoracic Society 2012 guideline

Asthma:
  • A chronic inflammatory condition in which airways are hyper-reactive to environmental (allergenic, irritants, infectious) and / or intrinsic factors
Key Points
  • Clinical suspicion should be confirmed with pulmonary function test for the presence of reversible airway obstruction
  • Regular reassessment of lung function to monitor asthma control
  • Management for children and adults are different
  • Self-management education – action plan is an essential component of asthma management
  • Controller therapy should be initiated in children and adults with one or more indicators of poor control

1 In patients of all ages with respiratory symptoms (acute, chronic, recurrent):
a) Include asthma in the differential diagnosis.
b) Confirm the diagnosis of asthma by appropriate use of: – history. – physical examination. – spirometry.

2 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.

3 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.

Diagnosis requires PFT

Symptoms include frequent episodes of

  • breathlessness, chest tightness, wheezing, or cough
  • often worse at night and early in the morning.
  • Often develop as a result of a trigger & improve in response to bronchodilator or anti-inflammatory therapy
  • Ask about playtime when asking Q about exercise induced asthma in children
Children
  • Severe wheeze / dyspnea
  • Wheeze/dyspnea started 3 episodes of wheeze
  • Chronic cough, at night or exercise
  • Clinical benefit from anti-ashtma meds
Children >6yo
  1. Spirometry: FEV1/FVC=12% after a bronchodilator or after course of controller Tx
  2. Alt: Peak expiratory flow increase >=20% after a bronchodilator or after course of controller Tx

Adults

  1. Spirometry: FEV1/FVC =12% & a min of >=200ml after a bronchodilator or after course of controller Tx
  2. Alt: Peak expiratory flow increase by 60L/min and a min of >=20%.
  3. Alt: Peak flow with diurnal variation >8% based on bid readings or >20% based on multiple daily readings

Alternative for both children and adult:

  1. Exercise Challenge >=15% decrease in FEV1 postexercise
  2. Methacholine challenge PC20<4mg/ml (4-16 borderline and >16 is negative)

4 In a known asthmatic with an acute exacerbation:
a) Treat the acute episode (e.g., use beta-agonists repeatedly and early steroids, and avoid under-treatment).
b) Rule out co-morbid disease (e.g., complications, congestive heart failure, chronic obstructive pulmonary disease).
c) 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).

Criteria for Hospital Admission
  • Unable to speak sentences
  • RR>25/min, HR>110 or bradycardia
  • PEF<40% predicted
  • Silent chest, cyanosis, confusion
Status Asthmaticus Tx
  • O2
  • ABG, PEF
  • Ventolin with spacer or neb
  • Ipratropium with spacer or neb
  • Epi sc / IM
  • prednison po or IV corticosteroid
  • IV salbutamol
  • IV fluid
  • Intubation prn
  • CXR (r/o PNA, CHF)
  • likely ICU admission

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

Management
  1. Every pt should receive self-management education with a written action plan.
  2. All pt should have access to a fast-acting bronchodilator
    • SABA: salbutamol, terbutaline, fenoterol
    • LABA: formoterol – only for >= 12yo on ICS
  3. Controller therapy should take current control & future risk for exacerbations into account
Regularly reassess at each visit
  1. control, adherence, and inhaler technique
  2. Triggers: allergens (mold, carpet, pets), occupational sensitizers, respiratory infections, exercise, and smoking
  3. co-morbidities: rhinitis, sinusitis, GERD
  4. Spirometry or PEF to assess lung function
  5. Sputum Eosinophils – >18yo with mod to severe asthma
  6. Growth in children should be monitored; ref to a specialist if a fall-off in growth
Prevention
  • Avoid Tobacco
  • Triggers ID and allergen systematically removed
    • exercise, viral illness, meds (beta blockers, NSAIDs), emotion
    • allergen, irritant (smoking) – consider injection immunotherapy to proven allergens if still symptomatic despite effort to avoid allergens

Management continuum (step-wise approach)
  1. SABA on Demand – very mild intermittent asthma
  2. ICS:
    • Introduce early as the initial maintenance Tx even
    • Low dose <=250mcg/d (200mcg 6-11yo)
    • Med Dose 251-500mcg/d (201-400mcg 6-11yo)
    • High dose >500mcg/d (>400mcg 6-11yo)
    • Second line monotherapy: LTRA (Leukotriene Receptor Antagonist) – approved for >12yo
  3. Not controlled on low dose ICS:
    • >12 yo add LABA (only used with combination of ICS)
    • 6-11yo increase ICS from low to medium dose (high dose ICS associated with sig S/E)
  4. >12 yo add LTRA or increase ICS;
    • 6-11yo add LABA or LTRA
  5. Anti-IgE (Omalizumab) – >12yo with atopic asthma or theophylline (adult only)
  6. Prenisone

After at least a few weeks to months of proper control, the medication should be reduced to the min necessary to achieve adequate asthma control and prevent future risk of exacerbations.


Asthma Control Criteria
  1. No absence from work or school due to asthma
  2. Normal Physical activity and Mild infrequent exacerbations
  3. No night time symptoms
  4. FEV1 or PEF >=90% personal best, PEF diurnal variation <=10-15%, Sputum eosinophils <2-3%

5 For the ongoing (chronic) treatment of an asthmatic, propose a stepwise management plan including: – self-monitoring. – self-adjustment of medication. – when to consult back.

Components of an asthma program – Written action Plan for self-management
  1. 6-11yo
    • Maintenance – none –> low dose ICS –> medium dose ICS –> ICS/LABA
    • Reliever: SABA
    • Step-up Tx (yellow zone): 1st choice: none
      • 2nd choice: 1mg/kg prednisone/prednisolone x 3-5 days
  2. >=12yo
    • Maintenance – none –> ICS –> ICS/LABA (Symbicort, Advair, or Zenhale)
    • Reliever: SABA or Symbicort
    • Step-up Tx (yellow zone):
      • 1st choice: >=4 fold increase ICS or Symbicort to a max of 4 inhalation bid x 7-14 days
      • 2nd choice: Prednisone 30-50mg x >5 days
  3. Reliever vs Controller & inhaler technique & medication safety & s/e
  4. Identify triggers

Combination Therapy: Not approved for <12yo
  • Symbicort – Budesonide / Formoterol
  • Advair – Luticasone / salmeterol
  • Zenhale – Mometasone/formoterol

asthma_image4


Reference:
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Posted in 7 Asthma, 99 Priority Topics, FM 99 priority topics, Resp

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