Download chronic asthma

CHRONIC ASTHMA
Resident Author: Julia Wystma. MD
Faculty Advisor: Lisa Bell, MD CCFP
Created: January 2012
Overview1,2,3
•
•
Asthma - inflammatory disorder of the airways characterized by paroxysmal or persistent symptoms (see below) with associated variable airflow limitation and airway hyper-responsiveness.
It is common (affects 12% of children and 8% of adults), has significant impact (mortality rate of 20 children/year and 500 adults/year, and leading cause of missed school and third for work)
Diagnostic Considerations
• Clinical diagnosis made by combining genetic predisposition, clinical signs and symptoms, and objective measures of lung function
• History: frequent episodes of dyspnea, wheezing, cough, or chest tightness
Symptoms often:
• Are worse at night and early morning or
• Develop with URTI, or after exercise/laughing/playing , or after exposure to allergens or irritants
• Improve with bronchodilators and steroids
• Physical exam: wheezing, tachypnea, decreased breath sounds, accessory muscle use, indrawing and nasal flaring
• Investigations: 3 methods for diagnosis- one preferred and two alternates (see Table 1)
Table 1. Diagnosis of asthma
Pulmonary function measurement
Criteria for children (ages ≥ 6)
Adult criteria
1) Preferred = Spirometry: showing reversible airway obstruction
Reduced FEV1/FVC
AND
Increase in FEV1 after a bronchodilator or course of
controller therapy
Less than lower limit of normal based on age, sex,
height, and ethnicity
AND
≥ 12%
Less than lower limit of normal based on age, sex,
height and ethnicity
AND
≥12% (and minimum ≥200mL)
2) Alternate = Peak expiratory flow (PEF) variability: showing variable airflow limitation
Increase after a bronchodilator or after a course of
controller therapy
OR
Diurnal variation
≥20%
OR
Not recommended
60L/min (≥20%)
OR
>8% based upon twice daily readings; >20% based
upon multiple daily readings
3) Alternate = Positive challenge test: showing airway hyper-responsiveness
Metacholine challenge
OR
Exercise challenge
•
PC20 < 4mg/mL (4-15mg/mL is borderline)
OR
≥10-15% decrease in FEV1 post-exercise
Differential diagnosis of coughing + wheezing by age:
o Infants and children: allergic rhinosinusitis, cystic fibrosis, enlarged lymph nodes, foreign body, heart disease, tumour, viral bronchiolitis, vocal cord dysfunction
o Adults: COPD, CHF, Ace inhibitor cough, post-nasal drip, GERD, pertussis, post-viral cough, mechanical airway obstruction, PE, pulmonary infiltration with eosinophils, vocal cord dysfunction
Management Considerations1,2,3,4
Management includes a) education b) pharmacotherapy, and c) regularly reassessment of control
A) Self-management education: ongoing (≥2x/year) education includes:
o Lifestyle: identify and avoid personal irritant and allergic triggers (ex. pets, mould, pollen, etc)
(see: http://www.uptodate.com/contents/patient-information-trigger-avoidance-in-asthma)
o Medications: review adherence, benefits, and side effects, and check inhaler techniques
(see: http://www.asthma.ca/adults/treatment/howToUse.php)
o Written action plan: a plan that outlines 1) daily preventative management for control 2) when and how to adjust reliever and controller therapy during exacerbations, and 3) when to seek urgent medical attention
(see: http://www.lung.ca/_resources/asthma_action_plan.pdf, or www.AsthmaActionPlan.com)
o Working with a support team (eg. asthma educator)
B) Pharmacologic management: use a step wise approach
1. Begin with reliever therapy
o Reliever therapy= SABA as needed. Indicated for all patients and as monotherapy for patients with mild infrequent symptoms and normal expiratory
flow.
2. If reliever use >3 times per week or any other indicator of poor control present (see Table 2) add on controller therapy starting with low dose ICS (or LTRA as second line for pediatrics)
o Controller therapy = daily ICS,ICS plus LABA, or LTRA. (see Table 3)
Dr. Michael Evans developed the One-Pager concept to provide clinicians with useful clinical information on primary care topics.
CHRONIC ASTHMA
Table 2. Indicators of asthma control
INDICATOR
FREQUENCY/VALUE
Daytime symptoms
<4 days/week
Night-time symptoms
<1 night/week
Physical activity
Normal
Exacerbations
Mild, infrequent
Absence from work/school due to asthma
None
Need for SABA
<4 doses/week
FEV1 or PEF
>90% personal best
PEF diurnal variation
<10-15%
3. If control suboptimal then adjust based on age (Table 3):
Table 3. Recommended controller therapy by age
6-11 years old
>12 years old
First line
low dose ICS
low dose ICS
Second line
med dose ICS
low dose ICS + LABA
Third line
med dose ICS + LABA
OR
med dose ICS + LTRA
med dose ICS + LABA OR
low dose ICS + LABA + LTRA
4. Additional considerations: consider oral steroids for severe symptoms, theophylline as fourth line in adults only, and omalizumab (XolairTM) for poor control of
atopic asthma in patients older than 12
C) Reassessment: assess control at each visit via history and objective measures (see Table 2) , as well assess inhaler techniques, adherence, triggers,
comorbidities, and growth in children. Patients on reliever-only therapy require yearly follow-up, patients on controller therapy should be seen at least twice a year.
Repeat spirometry every 1-2 years to assess airway function and response to treatment.
Pharmacotherapy 2,4,5
DRUG NAME
DRUG FORM
STRENGTH
ADULT DOSE
DOSE/DAY
AGE
COMMENTS
-side effects: tremor, nervousness, tachycardia, prolonged
QT, headache, hypokalemia, increased insulin secretion and
hyperglycemia (caution in diabetics)
Short-acting Beta2 Agonists (SABA)
Salbutamol
(VentolinTM)
MDI
100ug
1-2 puffs PRN
1200ug PRN
≥4y
Diskus
200, 400ug
200ug inh PRN
1600ug PRN
≥4y
Terbutaline
(BricanylTM)
Turbuhaler
500ug
500ug inh PRN
4000ug PRN
≥6y
Long-acting Beta2 Agonists (LABA)
Salmeterol
(SereventTM)
Diskus
50ug
50ug inh BID
100ug
≥4y
Formoterol
(OxezeTM)
Turbuhaler
6ug, 12ug
6-12ug puff BID
24-48ug
≥6y
-NOT as controller monotherapy , to be used as an add-on agent
with steroid (see below, LABA and ICS Combos)
-formoterol has faster onset and in an emergency may be used as
rescue therapy
-side effects: tachycardia and tremor (worse with formoterol)
-formoterol contains lactose
Long-acting Beta2 Agonist and Inhaled Corticosteroid Combos (LABA+ICS)
Formoterol +
Budenoside
(SymbicortTM)
Turbuhaler
6/100ug
6/200ug
2 puffs BID
1-4 puffs BID
≥12y
Salmeterol +
Fluticasone
(AdvairTM)
MDI
25/125ug
25/250ug
2 inh BID
1-2 inh BID
≥12y
Diskus
50/100ug
50/250ug
50/500ug
1 inh BID
1 inh BID
≥4y
Formoterol +
Memetasone
(ZenhaleTM)
MDI
5/50 ug
5/100 ug
5/200 ug
2 inh BID
2ihn BID
≥12y
-combo convenient but dose less flexible
-allows safe administration of LABA and may be steroid-sparing
-see LABA and ICS side effects
-symbicort contains lactose
-do not use 2 puffs on diskus, instead increase to next strength to
avoid LABA adverse effects
Inhaled Corticosteroids (ICS)
Fluticasone
(FloventTM)
MDI
50, 125, 250ug
2 puffs BID
100-2000ug
≥1y
Diskus
50,100, 250, 500ug
2 puffs 50-250 BID or
1 puff 250-500 BID
100-2000ug
≥4y
Budenoside
(PulmicortTM)
Turbuhaler
100,200,400ug
2 puffs BID
400-2400ug
≥6y
Beclomethasone
(QvarTM)
MDI
50, 100ug
2 puffs BID
100-800ug
≥5y
Ciclesonide
MDI
100,200,400 ug
1 puff daily
400ug
≥6y
(AlvescoTM)
-requires regular use
-use lowest effective dose, may try nocturnal use
-side effects: oral thrush and dysphonia (reduced with spacer and
rinsing), mildly reduced growth velocity in children for first year of
use (not sustained), at high doses may have adrenal dysfunction,
hyperglycemia, and osteoporosis
- increase risk of Cushing’s
CHRONIC ASTHMA
Leukotriene receptor antagonists (LTRA)
Montelukast
Tab
Age 1-5: 4 mg
chewable
Age 6-14: 5 mg
chewable
Age >14: 10 mg
10mg PO qhs
10mg
≥1y
Tab
20mg
20 mg PO BID
40mg
≥12y
(SingulairTM)
Zafirlukast
(AccolateTM)
-second/third-line controller
-usually used for pediatrics
-oral treatment option, good for patients with exercise
induced bronchospasm, ASA sensitivity, and allergic
rhinitis
-side effects: rare eosinophilic vasculitis, possible psych,
increased LFTs for zafirlukast
-drug interaction between zafirlukast and warfarin/
theophylline
*Asthma management in pregnancy
good asthma control is associated with improved neonatal outcomes and asthma medications have not been shown to increase the risk of fetal
malformations. Motherisk recommends that asthma treatment be similar for pregnant and non-pregnant patients (for further details please see: http://www.
motherisk.org/women/updatesDetail.jsp?content_id=296 )
Colour
Drug
BLUE
Salbutamol (Ventolin)
GREEN
Salmeterol (Serevent)
ORANGE
Fluticasone (Flovent)
PURPLE
Salmeterol/Fluticasone (Advair)
Patient Resource
(please also see resources under Self-Management stage of Management)
http://www.ginasthma.org/pdf/GINA_PatientGuide2007.pdf
http://www.lung.ca/diseases-maladies/asthma-asthme_e.php
Bottom Line
Asthma is chronic disease with paroxysmal symptoms that continues to cause significant morbidity and mortality. Diagnosis is made based on a combination of
clinical history and exam with objective measures of lung functions, with spirometry being the preferred method. Management involves patient education, step-wise
pharmacotherapy, and routine reassessment.
Abbreviations
SABA = short acting beta agonist
ICS = inhaled corticosteroids
LABA = long acting beta agonist
LTRA = leukotriene receptor antagonist
FEV1 = forced expiratory volume in 1 second
FVC = forced vital capacity
Diurnal variation = difference between morning pre-bronchodilator PEF and maximum daily, as percent maximum
PC20 = provocative concentration of metacholine producing a 20% fall in FEV1
References can be found online at http://www.dfcm.utoronto.ca/programs/postgraduateprograme/One_Pager_Project_References.htm