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ASTHMA
Objectives
1.
2.
3.
4.
5.
Definition of asthma
Causes of asthma and risk factors
Diagnosis
Treatment
Acute exacerbation of asthma
Asthma
Chronic disease of the airways that may cause
Wheezing
Breathlessness
Chest tightness
Nighttime or early morning coughing
Episodes are usually associated with widespread, but
variable, airflow obstruction within the lung that is
often reversible either spontaneously or with
treatment.
Definition :
• Chronic lung disease characterized by:
– Airway narrowing that is reversible (±
completely) either spontaneously or with
treatment
– Airway inflammation
– Airway hyper-responsiveness to a variety
of stimuli.
The Spirogram
Asthma Mortality Rates by Race
United States: 1979-2005
ICD-9
ICD-10
50
40
Black
Other
30
20
10
White
0
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
20
00
20
02
20
04
Rate per million
60
Source: Underlying Cause of Death; CDC National Center for Health Statistics
* Age-adjusted to 2000 U.S. population
Year
Risk Factors for Developing Asthma:
Genetic Characteristics
The body’s predisposition to develop an
antibody called immunoglobulin E (IgE) in
response to exposure to environmental
allergens
Environmental Facotors:
Viral/Bacterial infections
Chemical irritants: industrial,
household
Air pollution: CO, ozone
Tobacco smoke
Dust mite/cockroach allergens
Animal dander,
Exercise, cold air, emotion, stress
Genetic Factors:
Genetic alterations on
chromosomes 5 and 11,
and polymorphisms of
IgE
INFLAMMATION
Airway Hyper-responsiveness
Airflow Obstruction
Asthma Symptoms
Environmental Factors:
Biological Agents
Sufficient evidence of causal
relationship
House dust mite –
Chemical Agents
Sufficient evidence of causal
relationship
None found –
•
Sufficient evidence of association •
Environmental Tobacco –
Smoke (among pre-school
aged children)
Sufficient evidence of association •
None found –
Limited or suggestive evidence of
association
Cockroach (among pre-school –
aged children)
Respiratory syncytial virus –
(RSV)
•
•
Limited or suggestive evidence of
association
None found –
•
Diagnosing Asthma
*Troublesome cough, particularly at night
*Awakened by coughing
*Coughing or wheezing after physical activity
*Breathing problems during particular seasons
*Coughing, wheezing, or chest tightness after
allergen exposure
*Colds that last more than 10 days
*Relief when medication is used
Diagnosis of Asthma
• History of exercise or cold air participating dyspnea.
• PFT using spirometry with ≥ 12% improvement in
peak expiratory flow rate (PEFR) or peak expiratory
volume in one second (FEV1) after bronchodilator
administration helps in diagnosis.
• Skin prick tests to identify allergens.
Diagnosing Asthma:
Spirometry
Test lung function when diagnosing asthma
The Spirogram
Treatment of Asthma
Goals f oAsthma Management:
 Prevent chronic and troublesome symptoms (e.g., coughing
or breathlessness at night, in the early morning, or after
exertion ).
 Maintain normal or near normal pulmonary function.
 Maintain normal activity levels ( including exercise and
other physical activity.
 Prevent recurrent exacerbations of asthma and minimize
the need for emergency department visits or
hospitalizations.
 Provide optimal pharmacotherapy with minimal or no
adverse effects.
 Meet patients’ and families’ expectations of and satisfaction
with asthma care.
Pharmacological
treatment of asthma
1-Short-acting Inhaled 2-agonists
• Short-acting inhaled 2-agonists are the fastest acting and
most effective therapies for the relief of acute asthma
symptoms, including wheezing, dyspnea, and chest
tightness.
• 2-selective therapies (e.g., albuterol, pirbuterol, and
terbutaline)
• No clinical advantages among agents. Product selection
decisions should be based on factors, including patient
preference, cost of treatment, and availability of various
choices for delivery of inhalation therapy .
2-Long-acting Inhaled 2-agonists
• Currently, Formoterol and salmeterol are the only longacting inhaled 2-agonists available in the United States
• Causing bronchodilation by relaxing the smooth muscle
in the airway
• Monotherapy of LABA chronic use in the absence of
inhaled corticosteroids is not recommended
• Studies in adults and children with asthma have shown
that LABA monotherapy increases in the frequency of
asthma exacerbations
3-Leukotriene Modifiers
• Montelukast and zafirlukast
• Leukotriene modifiers prevent the action of
leukotrienes in the body. Leukotrienes are released
from mast cells, basophils and eosinophils. The release
of leukotrienes causes airway constriction, increased
mucus production, swelling and inflammation in the
lungs. This presents as wheezing, shortness of breath in
asthma
• These agents should be considered as alternatives to
inhaled corticosteroids and other treatments for
patients 12 years old and older with mild asthma
Leukotriene Modifiers cont
• Zafirlukast 10 mg 2 times/day is now approved
by the FDA for asthma management in children
7-11 years of age.
• Montelukast 10 mg/day is indicated for treating
asthma in patients 15 years and older, children
ages 6-14 years at 5 mg/day. and 2-5 years at
4mg/day.
• Both Zafirlukast and montelukast are effective
as monotherapy in asthma.
4- Inhaled Corticosteroids:
• Corticosteroids are the most potent and effective therapy
currently available for treating asthma .
• Topical used reduce the systemic exposure to these
agents by reducing absorption through the
gastrointestinal tract.
• Children should use spacer devices when using inhaled
corticosteroid .
• ICSs suppress inflammation in the lungs and are
recommended for prophylactic treatment of asthma.
LOW DOSE
Child
Beclomethasone
dipropionate
CFC-MDI
(42& 84μg/MD)
HFA-MDI
(40& 80μg/MD)
Budesonide
DPI( 200 μg/MD)
NEB( 200 & 500
μg/amp)
MEDIUM
HIGH
Adult Child Adult Child Adult
84-336
168 -504
336-672 504-840
>672
>840
80 -160
80 -240
160-320 240-480
>320
>480
200-400 200 -600
250 -500 Unknown
400-800 600-1.200 >800
>1.200
Unknown >1.000 Unknown
5001.000
LOW DOSE
Child
MEDIUM
HIGH
Adult Child Adult Child Adult
Flonisolid
CFC-MDI
(250 μg/MD)
500 -750
500-1.000 7501.250
Fluticasone
propionate
CFC-MDI
(44,110,220
μg/MD)
88 -176
88-264
Triamcinolone
acetonide
CFC-MDI
(100 μg/MD)
400 -800
400-1.000 8001.200
1.0002.000
176-440 264-660
1.0002.000
>1.250
>2.000
>440
>660
>1.200
>2.000
Corticosteroid
Flunisolide
Triamcinolone
Beclomethasone
Budesonide
Fluticasone
Inhaled
Receptor-binding
T ½(hrs)
Inhaled Bioavailability (%)
Affinity
1.6
3.6
UK
2.0
14.4
39
22
25
38
16-30
1.8
3.6
13.5
9.4
18
Nebulizer
Budesonide Inhalation Suspension :
• First inhaled corticosteroid product available for inhalation
by nebulizer. Two dosage strengths are available in 2 ml
single-dose ampules, 0.25 mg and 0.5 mg.
• The recommended starting dose depends on previous
corticosteroids therapy; 0.5 mg/day is suggested for patients
on previous inhaled asthma therapy, and 1 mg/day is
recommended for patients on oral corticosteroids .
New therapies
3- Formoterol:
• is a long-acting inhaled 2-agonist with a
duration of effect similar to that of salmeterol.
The faster onset of effect for formoterol, less than
5 minutes, is an advantage that distinguishes it
from salmeterol ( the onset of which is about 20
minutes ) .
”
+ Prednisone
Additional
3
therapy
(2) Short-acting 2-agonist on demand
(1) Environmental control and education
Severity of asthma
Very mild
Mild
Moderate
Symptom characteristics
Subclinical
Intermittent
Persistent
Moderately severe
severe
Device
Advantages
Disadvantages
Nebulizer
Simple to use (requires minimal Requires water-soluble drug
coordination) can be used in
.
mechanically ventialated patients Significant drug wasted
(residual volume)
Numerous factors can
affect delivery
Device variability ( brand to
brand, lt to lot )
Inconvenient, bulky, costly,
and time consuming
Requires electrical power
source
Nebulizer must be kept
clean ( potential for
infection)
costly
Device
Advantages
MeteredRequires minimal time for
dose inhaler treatments
Small, portable
Can be used in mechanically
ventilated patients.
MDI +
spacer
Reduce coordination required.
Improve pulmonary drug
deposition.
Reduces risk for adverse effects.
Disadvantages
Requires significant coordination
Device
Advantages
Dry powder Minimal coordination.
inhaler.
Improve pulmonary drug
deposition.
Lactose excipients.
Dusadvantages
Children+obstructed pt may not
generate adequate inspiratory
flow.
Increase cough.
Cannot be used in mechanically
ventilated pt.
Potential of drug aggregation.
Increase oropharyngeal drug
deposition and systemic
absorption.
Acute Asthma Exacerbation
Levels of severity of
acute asthma exacerbations
Near fatal
asthma
Raised PaCO2 and/or requiring mechanical ventilation with raised inflation
pressures
Although there are no universally agreed diagnostic
criteria for NFA, it is typically associated with the
presence of hypercapnia, acidemia, altered state of
consciousness and the development of
cardiorespiratory arrest requiring endotracheal
intubation and mechanical ventilation
Levels of severity of
acute asthma exacerbations
Near fatal asthma
Raised PaCO2 and/or requiring mechanical ventilation with raised inflation
pressures
Life threatening
asthma
Any one of the following in a patient with severe asthma:
• PEF <33% best or
• silent chest
predicted
• cyanosis
• SpO2 <92%
• feeble respiratory
• PaO2 <60 mmgh
effort
• normal PaCO2 (34 – 45 mmgh) • bradycardia
• dysrhythmia
• hypotension
• exhaustion
• confusion
• coma
Levels of severity of
acute asthma exacerbations
Near fatal asthma
Raised PaCO2 and/or requiring mechanical ventilation with raised inflation
pressures
Life threatening
asthma
Any one of the following in a patient with severe asthma:
• PEF <33% best or
• silent chest
predicted
• cyanosis
• SpO2 <92%
• feeble respiratory
• PaO2 <60 mmgh
effort
• normal PaCO2 (34 – 45 mmgh) • bradycardia
Acute severe
asthma
Any one of:
• PEF 33-50% best or predicted
• respiratory rate 25/min
• heart rate 110/min
• dysrhythmia
• hypotension
• exhaustion
• confusion
• coma
• inability to complete sentences in
one breath
Levels of severity of
acute asthma exacerbations
Near fatal asthma
Raised PaCO2 and/or requiring mechanical ventilation with raised inflation
pressures
Life threatening
asthma
Any one of the following in a patient with severe asthma:
• PEF <33% best or predicted
• silent chest
• SpO2 <92%
• cyanosis
• PaO2 <60 mmgh
• feeble respiratory
• normal PaCO2 (34 – 45 mmgh)
effort
• bradycardia
Acute severe
asthma
Any one of:
• PEF 33-50% best or predicted
• respiratory rate 25/min
• heart rate 110/min
Moderate asthma
exacerbation
• Increasing symptoms
• PEF >50-75% best or predicted
• dysrhythmia
• hypotension
• exhaustion
• confusion
• coma
• inability to complete sentences in
one breath
• No features of
acute severe asthma
Levels of severity of
acute asthma exacerbations
Near fatal asthma
Raised PaCO2 and/or requiring mechanical ventilation with raised inflation
pressures
Life threatening
asthma
Any one of the following in a patient with severe asthma:
• PEF <33% best or predicted
• silent chest
• SpO2 <92%
• cyanosis
• PaO2 <60 mmgh
• feeble respiratory
• normal PaCO2 (34 – 45 mmgh)
effort
• bradycardia
Acute severe
asthma
Any one of:
• PEF 33-50% best or predicted
• respiratory rate 25/min
• heart rate 110/min
Moderate asthma
exacerbation
Brittle asthma
• dysrhythmia
• hypotension
• exhaustion
• confusion
• coma
• inability to complete sentences in
one breath
• Increasing symptoms
• No features of acute severe asthma
• PEF >50-75% best or predicted
• Type 1: wide PEF variability (>40% diurnal variation for >50% of
•
the time over a period >150 days) despite intense therapy
Type 2: sudden severe attacks on a background of apparently
well-controlled asthma
Management of Asthma Exacerbations: Home
Treatment
Management of acute severe asthma
PEF >75% predicted
Time
Measure PEF and arterial saturations
PEF >75% best or predicted: mild
5 min
Give usual bronchodilator
15-30 min
Clinically stable AND PEF >75%
60 min
120 min
POTENTIAL DISCHARGE