BRONCHIAL ASTHMA
Dr Nilofer A R
Assistant Professor in OBG
Faculty of Medicine.
Definition
Asthma is a chronic inflammatory
disease of the airways which develops
under the allergens influence, associates
with bronchial hyperresponsiveness and
reversible obstruction and manifests
with attacks of dyspnea, breathlessness,
cough, wheezing, chest tightness and
sibilant rales more expressed at
breathing-out.
Etiology
As asthma is a
respiratory allergic
disease, the influence
of allergens
permeated into the
organism through
airways is essential
for the disease
development.
The allergens are
divided into:
•communal,
•industrial,
•occupational,
•natural
•pharmacological
Among the industrial allergens nitric,
carbonic, sulfuric oxides, formaldehyde, ozone
and emissions of biotechnological industry main components of industrial and
photochemical smog - must be mentioned.
The most important occupational
allergens are dust of stock buildings, mills,
weaving-mills, book depositories etc.
Natural allergens are represented by
plant pollen (especially ambrosia, wormwood and
goose-foot pollen) and different respiratory,
particularly viral, infections.
Some allergens which may
cause asthma
Spittle, excrements,
hair and fur
of domestic
animals
House-dust mites which
live in carpets, mattresses
and upholstered furniture
Plant pollen
Dust of
book
depositories
Pharmacological
agents (enzymes,
antibiotics,
vaccines, serums)
Food
components
(stabilizers,
genetically modified
products)
Pathologic anatomy
Macroscopic
changes:
viscous mucous/
mucopurulent phlegm
airway dyskinesia with
zones of spastic
contraction and
paralytic expansion of
bronchi
obstruction of airway
lumen
• lung emphysema,
pneumosclerosis
• RV and RA hypertrophy and
dilation
Microscopic changes:
Bronchial wall infiltration with mast cells,
eosinophils, basophils and T-lymphocytes
Edema of mucous and submucous tunics
Destruction of bronchial epithelium
Hypertrophy of bronchial smooth muscles,
Hyperplasy of submucous glands
Microvessels dilation
Classification
Depending on etiology asthma is divided
into exogenous (atopic) and endogenous (nonatopic). By clinical course asthma is divided into
intermittent (beginning, early) and persistent
(chronic, late). Depending on frequency of
exacerbations, limitations of patient’s physical
activity and lung function persistent asthma is
divided into mild, moderate and severe (lung
function is assessed by forced expiratory volume
in 1 second (FEV1) and peak expiratory flow (PEF)
and daily variability of these parameters). There
are also remission phase and exacerbations.
Asthma severity
classification
Clinical course,
severity
Intermittent
Mild
persistent
Daytime asthma
symptoms
Nighttime
awakenings
FEV1, PEF
< 1 /week
2 and <
/month
>80% predicted.
Daily variability <
20%
> 2 /month
>80% predicted.
Daily variability –
20-30%
> 1 /week
> 60 but < 80%
predicted.
Variability>30%.
Daily
<60% predicted.
Variability > 30%.
 1 /week
but not daily
Moderate
persistent
Daily
Severe
persistent
Persistent,
which limit
normal activity
Clinical manifestations
Classic signs and symptoms of
asthma are:
attacks of expiratory dyspnea
shortness of breath
cough
chest tightness
wheezing (high-pitched whistling
sounds when breathing out)
sibilant rales
In typical cases in development of asthma
exacerbation there are 3 periods – prodromal
period, the height period and the period of
reverse changes.
At the prodromal period:
vasomotoric nasal reaction with profuse watery
discharge,
sneezing, dryness in nasopharynx,
paroxysmal cough with viscous sputum,
emotional lability,
excessive sweating,
skin itch and other symptoms may occur.
At the peack of exacerbation there are:
expiratory dyspnea
forced position with supporting on arms
poorly productive cough
cyanotic skin and mucous tunics
hyperexpansion of thorax with use of all accessory
muscles during breathing
at lung percussion: tympanitis, shifted downward
lung borders
at auscultation: diminished breath sounds, sibilant
rales, prolonged breathing-out, tachycardia.
in severe exacerbations: the signs of right-sided
heart failure (swollen neck veins, hepatomegalia),
overload of right heart chambers on ECG.
At the period of the reverse changes,
which comes spontaneously or under
pharmacologic therapy,
dyspnea and breathlessness relieve or
disappear,
sputum becomes not so viscous,
cough turns to be productive,
patient breathes easier.
Asthmatic status
The severe and prolonged asthma exacerbation
with intensive progressive respiratory failure,
hypoxemia, hypercapnia, respiratory acidosis,
increased blood viscosity and the most important sign
is blockade of bronchial b2-receptors.
Stages: 1st - refractory response to b2-agonists (may
be paradoxical reaction with bronchospasm
aggravation)
2nd - “silent” lung because of severe bronchial
obstruction and collapse of small and intermediate
bronchi;
3rd stage – the hypercapnic coma.
In many cases asthma, particularly intermittent,
manifests with few and atypical signs:
episodic appearance of wheezing;
cough, heavy breathing occurring at night;
cough, hoarseness after physical activity;
“seasonal” cough, wheezing, chest tightness
(e.g., during pollen period of ambrosia);
the same symptoms occurring during contact
with allergens, irritants;
lingering course of acute respiratory
infections.
Asthma complications
The complications of
asthma exacerbations
are:
pneumothorax
lung atelectasis
pneumonia
acute or subacute cor
pulmonale
asthmatic status.
Persistent asthma causes:
fibrosing bronchitis
small bronchi
deformation and
obliteration
emphysema
pneumosclerosis,
chronic respiratory
failure
chronic cor pulmonale.
Asthma in childhood leads to growth inhibition
and thoracic deformation.
Investigations
Lab Data
Eosinophilia, moderate leukocytosis in
blood count as well as increased serum level of
Ig E can be found in patients with asthma,
especially at asthma exacerbations.
Inflammatory cells, Curschmann's
spirals (viscous mucus which copies small
bronchi)
and
Charcot-Leyden
crystals
(crystallized enzymes of eosinophils and mast
cells) can be observed in sputum.
Chest X-ray reveals:
hyperlucency of lung
fields
low standing and
limited mobility of
diaphragm
expanded intercostal
spaces
horizontal rib position.
ECG
especially in case
of severe,
persistent
asthma, shows
hypertrophy of
right heart
chambers.
Right axis deviation,
Rs type complex in V1 lead,
low amplitude R in V5-V6 leads
Lung function assessment
The diagnosis and severity assessment of
asthma is based mainly on parameters of lung
function. The most important of them are:
forced expiratory volume in 1
second (FEV1) and peak
expiratory flow (PEF), which
are measured
during spirometry
at forced
breathing-out.
PEF
Expiration
FEF
FEF
Flow
Inspiration
Volume
PIF
FEV1 and PEF
directly depend
on bronchial
lumen size and
elastic
properties of
surrounding
lung tissue.
Increase in FEV1 and PEF after inhalation of
bronchodilators (b2-agonists) of 15% and more
is specific for asthma.
PEF also can be measured with the help of
individual devices – peak flow meters
Diagnosis
Typical clinical
manifestations
and lung function
assessment are
sufficient for
diagnosis of
asthma.
includes:
Management
1. Avoiding the contact with allergen. If it is
impossible, the specific hyposensitization with
standard allergens should be performed. It is rather
effective in case of monoallergy, in intermittent and
mild persistent asthma, in remission phase.
2. Elimination of trigger factors (rational job
placement, changing the residence, psychological
and physical adaptation, careful drug using) is the
second condition for successful asthma treatment.
3. Optimally selected medical care is the base of
asthma management.
Drug therapy
2 drug categories are used:
Antiinflammatory drugs
(basic)
Are divided into:
hormone-containing
(corticosteroids)
nonhormone-containing
(cromones, leukotriene
receptor antagonists)
Bronchodilators
3 groups:
b2-agonists
anticholinergic drugs
methylxanthines
Corticosteroids
The working
mechanism lays in:
cell membrane
stabilization
inhibition of
inflammatory mediators
restoring the sensivity
of b2-receptors.
Inhaled corticosteroids
(beclamethazone,
inhacort, budesonide,
flixotid, fluticazone,
asmacort, asthmanex) are
the most effective and
safe and considered to be
the first line drugs for
asthma treatment.
Systemic are used during
short courses, mainly in
case of severe persistent
asthma or asthmatic
status.
Cromones
(cromolyn sodium –
intal, and nedocromil –
tiled)
stabilize cell membranes,
used mainly in pediatric
practice (in childhood)
in case of intermittent
or mild persistent
asthma.
Leukotriene
receptor
antagonists
(montelukast, zafirlukast)
have the moderate
intiinflammatory activity
used in case of aspirininduced asthma and
asthma of physical
exertion.
Bronchodilators
Anticholinergic
drugs
b2-agonists
Stimulates
b2-adrenergic
receptors of bronchi
Methylxanthines
Smooth
muscle
relaxation
reduce tonus
of vagus
inhibit phosphodiesterase
Inhaled b2-agonists are the basic drug
group among bronchodilators.
Short-acting (duration of action 5-6 h) b2agonists - salbutamol, fenoterol - are used
for quick relief of asthma symptoms.
Long-acting (> 12 h) b2-agonists salmoterol, farmoterol - for prevention of
asthma symptoms occurring.
Anticholinergic drugs (ipratropium bromide,
atrovent, troventol) are used predominantly in
nighttime asthma and in elderly patients
because of the least cardiotoxic effect.
Methylxanthines in comparison with other
bronchodilators have the less bronchodilating
potential. There are long-acting (>12 h) (theopec, theolong, theodur, euphilong) as
well as short-acting (aminophylline,
theophylline) drugs in this group.
Combined inhaled drugs (corticosteroids with b2agonists) – seretid, simbicort – with use of delivery
devices (nebulasers, turbuhalers, spasers,
spinhalers, sinchroners) enhance the effectiveness of
asthma therapy.
Management of
asthmatic status
Oxygen
Systemic corticosteroids (Hydrocortisone 200mg
or Methylprednisolone 125mg every 6h IV or
Prednisolone 50 mg/day per os)
Inhalations
of
short-acting
b2-agonists
Salbutamol 5mg or Fenoterol 2mg through
nebulaser – 3 times at 1st hour, then once an
hour till distinct improvement of patient’s condition
is achieved; then 3-4 times a day.
Inhaled anticholinergic drugs or Aminophylline IV.
If ineffective - artificial lung ventilation.
Prognosis
In case of early detection and
adequate treatment the prognosis
for the disease is favourable.
It becomes serious in severe
persistent and poorly controlled
(insensitive for corticosteroids)
asthma.
The examination of
working capacity
The patients with unfavorable for
the disease conditions of work need
the job replacement.
Physical labours with severe
asthma are disable to work.
Prophylaxis
Preservation of the environment,
healthy
life-style
(smoking
cessation, physical training) – are the
basis of primary asthma prophylaxis.
These measures in combination with
adequate drug therapy are effective
for secondary prophylaxis.
Thank you