Transcript asthma-phcp-403-2017

ASTHMA
ASTHMA CASE STUDY
A 3-year-old boy comes into A&E with a severe asthma attack. This is
his third in the last three months. He is started on nebulized salbutamol,
intravenous aminophylline and oral prednisolone. The presenting
symptoms include: tachycardia rapid breathing peak expiratory flow
rate (PEFR) <50% normal unable to talk due to breathlessness.
Three days later, after being stabilized on the ward, he is discharged on
salbutamol and beclometasone inhalers (same as on admission) plus a
leukotriene antagonist.
Questions
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What is asthma?
How does early childhood asthma often present?
What are the common symptoms?
What class of drug is used for the initial pharmacological
management of asthma and how do they work?
What route of administration is usually used initially and
why?
What are the main side-effects of this class of drugs?
What are the classes of the drugs being used here to
treat the severe asthma attack and how will they help?
What side-effect do they all have in common which can
be exacerbated by hypoxia, a common feature of severe
asthma?
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What step of the British Thoracic Society guidelines is the boy now on?
What is the role of the leukotriene antagonist?
What preparations are available and which would probably be most
suitable for
this 3-year-old boy?
What is the most suitable way to administer the beclometasone to this
3-year-old
and why?
How should the administration device be cared for and why?
What are the other main devices used to administer medication in
asthma?
With a patient with severe asthma such as this, is there any advice that
the family
can follow at home if an acute asthma attack starts again?
Can you suggest a way that the family can monitor response to therapy
Definition:
• The Global Initiative for Asthma (GINA)2003 guideline
describes asthma as a ‘chronic inflammatory disorder of the
airways in which many cells and cellular elements play a role.
• The chronic inflammation causes an associated increase in
airway hyper-responsiveness that leads to recurrent episodes
of wheezing, breathlessness, chest tightness and coughing,
particularly at night or in the morning.
• The episodes are usually associated with widespread but
variable airflow obstruction which is often reversible either
spontaneously or with treatment.
ETIOLOGY
Childhood onset asthma
It is associated with atopy, which is the genetic predisposition for
the development of immunoglobulin E (IgE) mediated response to
common aero allergens.
Atopy is the strongest factor in the development of asthma.
A positive family history of asthma and allergy to tree and grass
pollen, house dust mites, household pets, and mold is associated
with increased incidence of Asthma in Children.
Adult-onset asthma
May also be associated with atopy, but many adults with asthma
have a negative family history and negative skin tests to
common allergens. Some of these patients may have nasal
polyps, aspirin sensitivity, and sinusitis.
DIAGNOSIS
Diagnosis of asthma is based primarily on:
• A detailed history of intermittent symptoms of wheezing,
chest tightness, shortness of breath and coughing.
• These episodes may be worse seasonally (e.g. springtime or
late summer and early fall) or in association with exercise.
• History of nocturnal symptoms with awakenings in the early
morning is a critical component to assess.
• In addition history of symptoms after exposure to common
triggers (e.g. .cats, perfumes, and tobacco smoke)
Pulmonary Function Test
Diagnosis of asthma is based in part on demonstration of reversible
airway obstruction. A short summary of arterial blood gases is
important in assessing the severity of asthma.
Spirometry
Lung volumes often are measured to obtain information about the
size of the patient’s lungs, because pulmonary diseases can affect
the volume of air that can be inhaled and exhaled.
The spirometry can also be used to evaluate the performance of the
patients lungs, thorax and respiratory muscles in moving air into
and out of the lungs.
The FEV is measured by having the patient exhale into the
spirometer as forcefully and completely as possible after maximal
inspiration.
A spirometer is a device that is used to
measure the function of the lungs and the
airways.
There are different tests in spirometry.
The most important test is the Forced
Vital Capacity or FVC. To perform a Forced
Vital Capacity test, the patient takes a
breath as deep as he possibly can and
than expires as hard and as fast as he can
in the spirometer. After the forced and
complete expiration he takes another
breath as deep and as fast as he can.
Trigger factors that may cause asthma
Trigger
Examples
Allergens
Pollens, moulds, house dust mites
Industrial chemicals Epoxy resins, aluminium, hair sprays
Drugs
Aspirin, ibuprofen, β-adrenoceptor blockers
Foods
Nuts, dairy products, food colouring,
Industrial triggers
wood or grain dust, cotton dust, cigarette
smoke
Miscellaneous
Cold air, exercise, viral, respiratory track
infections.
Pathophysiology
Asthma is caused by a complex interaction between
inflammatory cells and mediators.
Mast cells, eosinophils, T lymphocytes, neutrophils, and
epithelial cells are all of importance.
After exposure to an asthma-precipitating factor( e.g.
aeroallergens), inflammatory mediators are released
from bronchial mast cells, macrophages, T lymphocytes,
and epithelial cells. This cells act on the airways to
cause inflammation, either directly or through neutral
mechanisms.
Pathophys cont.…..
Their exact roles and interrelationships with each other
and with the causatives allergenic or non-allergenic
mechanisms are yet to be fully determined.
These cell-derived mediators play a role in causing the
main features of asthma: marked hypertrophy and
hyperplasia of bronchial smooth muscles, mucus gland
hypertrophy leading to excessive mucus production and
airway plugging, airway oedema, acute
bronchoconstriction, and impaired mucociliary
clearance.
cells
Asthma
precipitating
factor
mast cell, macrophage, neutrophil,
eosinophil, lymphocyte
mediators
a
Histamine, leukotriene's,
prostaglandins, interleukins etc
Airway inflammation, airway smooth muscle contraction,
increased vascular permeability, mucous hyper secretion,
airway injury, epithelial damage
asthma attack
GOAL OF THERAPY
Aims of management of asthma are to achieve good long term
asthma control. Features include
Normal (> 80% of predicted) or near normal lung function
Good exercise performance, which is unimpaired by asthma.
Minimal need for short-acting β2-agonist as required
Absence of exacerbations
Meet patients and families expectations of satisfaction with asthma
care
Reduce risk
Prevent recurrent exacerbation of asthma and minimize the need
for hospitalizations
Prevent progressive loss of lung function
Provide optimal pharmacotherapy with minimal or no adverse
effects
• classify severity of asthma
– intermittent or persistent?
moderate
persistent
mild
persistent
mild
intermittent
severe
persistent
MANAGEMENT OF ASTHMA
Non- Pharmacological
Patient education and the teaching of self-management skills
should be the cornerstone of the treatment program. Selfmanagement programs improves adherence to medication and the
use of health care services.
Avoidance of known allergenic triggers can improve symptoms,
reduce medication use and decrease bronchial hyperresponsiveness.
Patients with acute severe asthma should receive supplemental
oxygen therapy by mask or nasal cannula.
Proper steps to the use of inhalers should be followed
Summary of stepwise management in adults
symptoms
Nighttime
symptoms
Step 4
Severe
persistent
Continual symptoms
Limited physical activity
Frequent exacerbations
frequent
Step 3
Moderate
persistent
Daily symptoms
Daily use of inhaled SABA
Exacerbations affect activity
Exacerbations ≥2 times/week; may last days
> 1 time a week
Step 2
Mild
persistent
Symptoms >2 times/week but <1 time/day
Exacerbations may affect activity
> 2 times a month
Step 1
Mild
intermittent
Symptoms ≤ 2 times/week
Asymptomatic and normal PEF between
exacerbations
Exacerbations brief (from a few hours to a
few days); intensity may vary
≤ 2 times a month
stepwise approach for the management of asthma in adults & children >5 yrs
Long-term
control therapy (LTCT)
Quick relief
education
Step 4
severe
persistent
Daily medications:
ICS (high dose) + I-LABA (+
SR theophylline if inhaled) +
CST (≤60mg) or tablet
I-SABA as needed
Increasing daily use
indicate need for
additional LTCT
Individual education
and counselling in
addition to steps 2
and 3 actions
Step 3
Moderate
persistent
Daily medications:
Either: ICS (medium dose) or
ICS (low dose) + I-LABA +
SR theophylline
If needed ICS (medium-high
dose) + I- LABA
-do-
Step 1 action in
addition to selfmonitoring and refer
to group education if
available
Step2
Mild
persistent
One daily medication
ICS (low doses) or cromolyn
-do-
Step 1
Mild
intermittent
No daily medication needed
Use of I-SABA >2
times /week may
indicate the need
for long term
control
Teach basic facts
about asthmadiscuss inhaler
technique, roles of
medications,
triggers, self
monitoring etc
To use an MDI:
1.Shake the inhaler well before use (3 or 4 shakes)
2.Remove the cap
3.Breathe out, away from your inhaler
4.Bring the inhaler to your mouth. Place it in your
mouth between your teeth and close your mouth
around it.
5.Start to breathe in slowly. Press the top of you
inhaler once and keep breathing in slowly until you
have taken a full breath.
6.Remove the inhaler from your mouth, and hold your
breath for about 10 seconds, then breathe out.
CHRONIC ASTHMA
The Pharmacological management of asthma depends on the
frequency and severity of a patient’s symptom. Infrequent attacks
can be managed by treating each attack when it occurs, but with
more frequent attacks preventive therapy needs to be used.
Treatment of chronic asthma is usually given in a stepwise
progression, according to the severity of the patient’s asthma
symptoms and response to current treatment.
Reliever medication is used for agents that give immediate relief of
symptoms. While agents that act to reduce inflammation or give
long-term bronchodilator are referred to as “Controller” Protectors
or “Preventers”
RELIEVER MEDICATION
β- adrenorceptor agonist bronchodilators
They are the mainstay of asthma management.
Salbutamol and terbutaline are selective β2- agonist
and have few β1- mediated side effects. Inhaled β2agonist is the first line agent. It is used as required by
the patient for the symptomatic relief of
breathlessness and wheezing e.g. Salbutamol 200µg
when required. Additional bronchodilators may be
required if the therapy above does not adequately
control symptoms.
Inhaled anticholinergic agents
These block muscarinic receptors in bronchial smooth muscle and
can be added to the treatment regimen. They have slower onset of
action than β2- agonist but a longer duration of action.
3. Oral-bronchodilators
Oral bronchodilators can also be added, for example theophylline at
step 3 or β2-agonist at step 4 for additional symptom control. Oral
bronchodilators may also become necessary in patients who are
unable to use inhaler therapy effectively.
Theophylline should be started at a dose of 400-500mg/day in
adults and if required, increased after 7 days to 800-1000mg/day. It
has a narrow therapeutic index and its hepatic metabolism varies
greatly between individuals. Plasma levels will be taken every 34days.
CONTROLLER MEDICATIONS
Inhaled anti-inflammatory agents
Regular anti-inflammatory treatment should be used for patients
with recent exacerbation, nocturnal asthma, impaired lung function
or if using their inhaled bronchodilator more than once a day.
Corticosteroids are the most commonly used anti-inflammatory
agents but others such as the chromones are available.
Corticosteroids
They suppress the chronic airway inflammation associated with
asthma. At present, inhaled corticosteroids are the initial drugs of
choice, with a starting dose for an adult of beclomethasone or
budesonide 400µg per day. In individual doses,
Corticosteroids according to a guideline recommends considering
steroids for patients with any of the following;
Exacerbation of asthma in the last 2 years
Using inhaled β2-agonist three times a week or more.
Symptoms three times a week or more, or waking one night a week.
If symptoms persist, the steroid dose is increased stepwise
accordingly. Once symptoms and peak flow rates have improved the
dose of inhaled corticosteroids should be reduced.
Side effects
Those associated with high steroids includes.Oropharyngeal such as
Candidiasis. Measures to reduce or minimize this include the use of
a large volume spacer device and rinsing the mouth with water or
brushing teeth after inhalation.
Cromones
Inhaled sodium cromoglycate and nedocromil sodium are
less effective than corticosteroids in asthma. Although
rarely used, they may be possible alternatives if
corticosteroids cannot be tolerated.
Long acting β-adrenoceptor agonist bronchodilators(LABA)
When low-dose inhaled steroids fail to control asthma
symptoms adequately at step 3, long-acting β2- agonists
should be added instead of increasing the steroid dose.4-6
weeks should be used as a trial period to assess if the LABA
has been effective and whether treatment needs to be
added or changed. Patients should be reminded
that these agents are an addition to their short-acting agents, not
a replacement and are unsuitable for acute symptoms relief due
to their slower onset of action.
Leukotriene antagonist
Two leukotriene receptor antagonists, montelukast and zafirlukast
are available, but they are less effective than corticosteroids in
controlling asthma. They are effective in combination with steroids
and are included in step 4 as add-on therapy for adult patients. They
have a value in aspirin-induced asthma, possibly due to the role of
leukotriene in this form of asthma.
Anti-IgE Monoclonal antibodies
Omalizumab is the first of its kind to be marketed. It
might be of benefit to patients with severe persistent
allergic asthma.
Oral corticosteroids
Oral corticosteroids should only be used at step 5, if
symptoms control cannot be achieved with maximum
doses of inhaled bronchodilators and steroids. They
should be administered as a single morning dose to
minimize adrenal suppression. Alternate-day dosing
produces fewer side effects but is less effective in
controlling asthma.
ACUTE SEVERE ASTHMA
The management of acute asthma depends on the
severity of the attack and its response to treatment as
well as an appreciation of the patients past history and
present treatment. If an acute attack becomes
persistent and difficult to treat, it is known as acute
severe asthma.
The aim of treatment is to prevent any deterioration in
the patient’s condition and hasten recovery.
Management of acute severe asthma
The immediate treatment of acute severe asthma should take
place in the patients home, on the way to the hospital, or on
admission.
Oxygen at high conc is administered, at high flow rates,
particularly for severe and life threatening exacerbations. A β2agonist is administered which gives a prompt bronchodilation
lasting 4-6 hrs.
In mild to moderate exacerbations the β2- agonist can be
administered by metered dose inhaler with a spacer
attachment(4-6 puffs)
Corticosteroids are also given in acute attack if PEFR is below
50%.
Intravenous hydrocortisone (100mg) should only be
used if the patient cannot take oral medication, if life
threatening features are present, such as cyanosis,
bradycardia, confusion, exhaustion or
unconsciousness, higher dose bronchodilators are
used: Salbutamol 5mg with ipratropium bromide
500µg, repeated after 15mins and regularly if
required.Anticholinergics (iv aminophylline) can be
given with a bolus dose of 250mg over 30mins,
followed by a cont. infusion of 500 µg/kg/hr.
STEPWISE MANAGEMENT OF ASTHMA IN ADULTS
STEP 5:CONTINUES OR FREQUENT USE OF ORAL
STEROIDS
Use daily steroid tablets in lowest dose providing
adequate control
Maintain high dose inhaled steroid at 2000µcg/day
Consider other treatments to minimize the use of
steroids tablets
Refer patients for specialist care
STEP 4: PERSISTENT POOR CONTROL
Increasing inhaled steroids up to 2000µcg/day
Addition of a fourth drug e.g. leukotriene receptor
antagonist, SR theophylline, β2 agonist tablet
STEP 3:ADD-ON THERAPHY
1. Add inhaled long acting β2 agonist (LABA)
2. Assess control of asthma:
Good response to LABA-continue LABA
Benefit from LABA but control still inadequate- continue
LABA and increase inhaled steroids dose to 800µcg/day (if
not already on this dose)
No response to LABA- stops LABA and increase inhaled
steroid to 800µcg/day. If control still inadequate, institute
trial of other therapies, e.g. leukotriene receptor
antagonist or SR theophylline.
STEP 2: REGULAR PREVENTER THERAPY
Add inhaled steroids 200-800µcg/day
400µcg is an appropriate starting dose for many
patients
Start a dose of inhaled steroid appropriate to
severity of disease
STEP 1: MILD INTERMITTENT ASTHMA
Inhaled short-acting β2-agonist as required
PATIENTS CARE
• Patient’s knowledge about their asthma therapy is a
necessary component of management.
• They should have an understanding of the action of each of
the medicines they use.
• Education programmes must also look at a way of
modifying a patient’s behavior and attitude to asthma.
• The appropriate choice of inhalation device should be
made and education on proper usage.
• Counseling should lead to increased patients confidence in
the ability to self- manage asthma.
• Decreased hospital admission rates and emergency visits by
primary care doctors, increased compliance and improved
quality of life.
Large volume spacer
Technique
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5
shake the inhaler
fix MDI into the spacer
use one dose at a time
breath in asap after activating
breath in and hold breath
DPIs
Breath activated dry powder inhaler
Technique depends on device (read
manufacturer info leaflet for patient
counselling)
Inspiration generates turbulence,
disperses the particles in the inspired air
Powder is contained in capsule, circular
disk or special apparatus
Propellant free
Nebuliser
Produces an aerosol by blowing air or oxygen through a
reservoir of solution to produce droplets used with a
facemask or mouthpiece
Up to 10 times the amount of drug required in a
nebulizer to produce the same degree of
bronchodilation achieved by an MDI
Used :
Severe attacks
May avoid the need for IV drugss
REFRENCES
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