Transcript File - eCommons@AKU

An overview of Bronchial Asthma
by
Prof Nadeem Rizvi
F.R.C.P. U.K
Head of Chest Medicine
Jinnah Postgraduate Medical Centre
Karachi
Asthma: Disease State
Overview
Asthma is a chronic inflammatory disorder
of the airways that is characterized, in
particular, by the infiltration of activated
eosinophils, macrophages, T lymphocytes,
and mast cells, resulting in airway
hyperresponsiveness and variable and at
least partially reversible airflow obstruction.
Magnitude of the Problem
• 300 million asthmatics worldwide
• Prevalence increasing in most countries
by 20% to 50% every 10 years
• An estimated 1 million deaths each
decade
• Significant cause of school/work
absence
• High healthcare expenditures,
especially for emergency services
Prevalence of Asthma
ISAAC Study:
The Lancet.
Vol 351. April
25, 1998
Prevalence of Asthma in Adults
2006
AIRP
MU
PakistanX
5%
Asthma Insight &
Reality in Pakistan
KH
I
Risk factors for Asthma
• Asthma occurs in families
• Atopy: the strongest identifiable risk factor
for the development of asthma
• Allergen exposure and chemical sensitizer
• Contributing factors may increase
susceptibility to development of asthma in
predisposed individuals
Risk factors for developing Asthma
Predisposing factors
 Atopy
 Gender
Casual factor

indoor allergens
 Domestic Mites
 Animal Allergens
 Cockroach Allergens
 Fungi
Out door Allergens
 Pollens
 Fungi
 Occupational Sensitizers
Contributing factors
 Respiratory infections
 Small size at Birth
 Diet
 Air pollution
 Outdoor pollutions
 Indoor pollutions
Smoking
 Passive smoking
 Active smoking
Pathophysiology
NUCLEUS
GRANULES
HISTAMINE
PAF
THROMBOXANE
PROSTACYCLIN
PROSTAGLANDINS
LEUKOTRIENES
MEDIATORS
ALLERGEN
Early and late phase response to
allergen challenge
Late:
Edema
Secretions
Inflammation
Early:
Bronchoconstriction
FEV1
1
2
3
4
5
6
7
Hours After Challenge
Medicine 1995;265-269
8
9
10
Balance between Th1-Type and Th2-Type Cytokine Responses
in Asthma Busse et al NEJM 2001
Environmental
Exposure
Genetic
Predisposition
Airway
Inflammation
Airflow
Limitation
Airway
Hyper-responsiveness
Asthma
Symptoms
Bronchoconstriction
Before
10 Minutes
After Allergen
Challenge
Airway Mucosal Edema
Diagnosis of Asthma
“Clinical is Best”
• History
• Physical examination
• Peak flow meter reading (reversibility of
15%)
Peak Flow Meter
Prednisolone
(40mg/day)
400
Bectomethasone
dipropionate
(400mcg/day)
300
200
100
1
5
10
15
DAY
20
25
28
Record of PEFR measured six-hourly in an asthmatic patient, showing
the characteristic variability and morning dip.
500
450
400
300
500
Salbutamol
Exercise
400
300
15% fall from
baseline value
200
100
Time
(Mins)
5
10
15
20
Effective Asthma management
• Use key indicators to make an accurate,
timely diagnosis
• Eliminate causal factors
• Initiate appropriate therapy
• Educate patient and family
• Follow up and adjust the treatment plan
• Monitor compliance
Gap in Asthma treatment
•
Patients are not detected
– do not seek medical attention
– no access to health service
– missed diagnosis (bronchitis, LRTI)
•
Patients do not get treated
– they do not want treatment (do not accept
diagnosis)
– they stop treatment (when they feel well)
– health service does not provide treatment
Asthma in the Developing World
• Ignorance is rampant
• Delivery of health care is not satisfactory
• Discrimination is still present
• Marriage for girls is often difficult without
concealing illness
• Schooling and play is often affected
Asthma Medications
• Controllers
– Medications used on a long-term basis to
achieve and maintain control of persistent
asthma
• Relievers
– Medications that act quickly to relieve
bronchoconstriction and its accompanying
acute symptoms; often referred to as rescue
medications
Classification of Asthma Medication
Quick Relief
Preventive
• Short-acting b2-agonists
Corticosteroids
– Salbutamol
– Terbutaline
• Anticholinergics
– Ipratropium Bromide
• Short-acting theophylline
– Aminophylline
•
– Beclomethasone
– Budesonide
– Fluticasone
Sodium Cromoglycate
•
Anti-Leukotrienes
•
Long-acting b2-agonists
– Sustained-release salbutamol
• Adrenaline injections
– Salmeterol
– Formoterol
•
Long-acting theophylline
Oral Therapy vs. Inhaled Therapy
High dose required (mg)
Much lower dose required
(mcg)
GI tract
Oral
cavity
Systemic
circulation
Targeted therapy to the
airway
Airways
Higher incidence of adverse
effect
Lower incidence of adverse
effects
‘If a patient uses quick-relief
medications every day, or even
more than three or four times a
week, daily long-term preventive
medications should be added to
the treatment plan.’
TREATMENT WITH
A BRONCHODILATOR
TREATMENT WITH A
BRONCHODILATOR AND
AN INHALED STEROID
Asthma Management
• At present, inhaled glucocorticosteroids
are the most effective controller
medications and are recommended for
persistent asthma at any step of severity
• Long-term treatment with inhaled
glucocorticosteroids markedly reduces the
frequency and severity of exacerbations
Steroid Effects in Asthma
ERS/ATS Joint Course on Basics in Asthma – Oslo June 8-10 2005
for Asthma Controller Therapy
Rate ratio for death
from asthma
2.5
2.0
1.5
1.0
0.5
0.0
0
1
2
3
4
5
6 7
8
9 10 11 12
No. of canisters of inhaled
corticosteroids per year
Inhaler use in Pakistan
NSRIDs
0%
A Cholin
1%
Cortics
8%
B2+Cortic
15%
B2 stim
76%
Asthma
Management
according to Guide
lines
Classification of asthma severity
STEP 4: SEVERE PERSISTENT
Step
down
when
•ICS (>1000 µg)+ inh LABA, + 1 of the following, if needed:
controlled
•Theo; LTM, oral LABA or oral steroid
CONTROLLER:
daily multiple medications
Avoid or control triggers
STEP 3: MODERATE PERSISTENT
CONTROLLER:
daily medications
•ICS (200–1000 µg)
+ inhaled LABA
Other options:
• ICS (500-1000 µg)
•+ theo or oral LABA
•LTM ICS >1000 µg
Avoid or control triggers
STEP 2: MILD PERSISTENT
CONTROLLER:
daily medications
•ICS (500 µg BDP
or equivalent)
Other options:
•Theophylline
•SCG
•LTM
Patient education
essential at every
step
Reduce therapy
if controlled for at
least 3 months
Continue
monitoring
Avoid or control triggers
STEP 1: INTERMITTENT
CONTROLLER:
none
RELIEVER
•Inhaled b2agonist prn
Avoid or control triggers
TREATMENT
Step up
if not controlled
(after check on
inhaler technique
and compliance)
Pharmacologic Management:
STEPWISE APPROACH
Once control is achieved & maintained for at least 3
months, gradual reduction of therapy should be tried.
4
3
2
1
Moderate
persistent
Mild
persistent
Intermittent
Severe
persistent
Multiple daily
controllers
Best
possible
results
Two daily
controllers
One daily
controller
No controller needed
Asthma
Control
Levels of Asthma Control
Characteristic
Controlled
Partly controlled
(All of the following)
(Any present in any week)
Daytime symptoms
None (2 or less /
week)
More than
twice / week
Limitations of
activities
None
Any
Nocturnal
symptoms /
awakening
None
Any
Need for rescue /
“reliever” treatment
None (2 or less /
week)
More than
twice / week
Lung function
(PEF or FEV1)
Normal
< 80% predicted or
personal best (if
known) on any day
Exacerbation
None
One or more / year
Uncontrolled
3 or more
features of
partly
controlled
asthma
present in
any week
1 in any week
REDUCE
LEVEL OF CONTROL
TREATMENT OF ACTION
maintain and find lowest
controlling step
partly controlled
consider stepping up to
gain control
INCREASE
controlled
uncontrolled
exacerbation
step up until controlled
treat as exacerbation
REDUCE
INCREASE
TREATMENT STEPS
STEP
STEP
STEP
STEP
STEP
1
2
3
4
5
• Asthma is chronic inflammatory disorder
• Inhaled steroids is a corner stone of asthma
management
• Use of peak flow meter is essential, in
diagnosing and assessing severity
• Management should depend on the level of
asthma control
• Choice of delivery device should be
acceptable and east to use
Teach People to
‘Live with asthma’
Thank you
DISADVANTAGES OF MDI
• highly technique-dependent, requiring
– proper hand-lung coordination
– slow deep inhalation
– long breath-holding time
• high particle velocity
• propellant issues (CFC/HFA)
– not all molecules compatible with HFA
• errors in technique common
• noncompliance common
Asthma
Management
according to Guide
lines
Where we are now! (in the U.S.)
Metered-Dose Inhaler
Handihaler®
Aerolizer™
Twisthaler®
Turbuhaler®
Autohaler®
Spacer Devices
Diskus®
Small Volume
Nebulizer
Consequence of Poor MDI/DPI
Technique
•
•
•
•
•
•
Overuse of medication
Wasted medication
Lung deposition substantially reduced
Overall suboptimal therapy
Increased costs
Efficacy considerably compromised