Presentation

1. ASTHMA
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2. Definition
 chronic inflammatory disease of
airways that is characterized
 airflow obstruction,
 Bronchial hyperresponsiveness,
 and an underlying inflammation process.
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3.  Interaction
between these
features determine
the response and
severity of asthma.
 Treatment of
asthma targets
these same fetures
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4. Pathophysiology and
Pathogenesis of Asthma
 Airflow limitation is recurrent and
caused by a variety of changes in the
airway.
 These include:
 Bronchoconstriction
 Airway oedema
 Airway hyperresoponsibility
 Airway remodelling
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5.  Bronchoconstriction may result from
 IgE-dependent release of mediators from mast cells
ie.
 histamine,
 tryptase,
 leukotrienes, and
 prostaglandins that directly contract airway smooth
muscle
 non-IgE-dependent response also involves mediator
release from airway cells eg. As induced by aspirin
 other stimuli
 exercise,
 cold air,
 irritants
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6.  As disease becomes more persistent
and progressive other factors limit
outflow
 oedema
 Inflammation
 Mucus hypersecretion
 Formation of inspissated mucus plugs
 Hypertrophy and hyperplasia of the
airway smooth muscle
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7.  Airway hyperresponsiveness
 An exaggerated bronchoconstrictor response to
a wide variety of stimuli.
 Airway Remodeling
 Permanent structural changes may occur in
airways. include
 Inflammation
 Mucus hypersecretion
 Subepithelial fibrosis
 Airway smooth muscle hypertrophy
 Angiogenesis
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10. Pathogenesis
 is a complex, interactive process that
depends on the interplay between
two major factors—
 Host factors
 Environmental exposures
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12.  Host factors
 Innate immune system
 Genetics
 Asthma has an inheritable component
 Sex
 In early life prevalence of asthma is higher in
boys
 At puberty it is higher in girls
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13.  Environmental factors
 Allergens
 Respiratory Infections
 Other environmental factors
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14. Clinical Features
 History of any of the following:
 Cough, worse particularly at night
 Recurrent wheeze
 high-pitched whistling sounds when
breathing out—especially in children.
 Lack of wheezing and a normal chest
examination do not exclude asthma
 Recurrent difficulty in breathing
 Recurrent chest tightness
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15. Clinical features continued
 Symptoms occur or worsen in the
presence of
 Exercise
 Viral infection
 Animals with fur or hair
 House-dust mites (in mattresses, pillows,
upholstered furniture, carpets)
 Mold
 Smoke (tobacco, wood)
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16. Clinical features continued
 Pollen
 Changes in weather
 Strong emotional expression (laughing or
crying hard)
 Airborne chemicals or dusts
 Menstrual cycles
 Symptoms occur or worsen at night,
awakening the patient.
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17.  Physical examination
 Hyperexpansion of the thorax,
 wheezing during normal breathing,
 Chest may be silent in severe cases
 Paradoxical pulse
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18. Differential Diagnosis
 COPD
 cardiac disease
 Tumour
 laryngeal
 tracheal
 - lung
 bronchiectasis
 foreign body
 interstitial lung disease
 pulmonary emboli
 aspiration
 vocal cord dysfunction
 hyperventilation
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19. Investigation
 Peak Expiratory Flow
 Forced Expiratory Volume in one
second
 CXR
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20. Treatment of acute asthma
 OXYGEN
 Give high flow oxygen to all patients with
acute severe asthma.
 b2 AGONIST BRONCHODILATORS
 Inhaler salbutamol
 Nebulisation
 STEROID THERAPY
 Give steroid tablets in adequate doses in all
cases of acute asthma.
 parenteral hydrocortisone 400 mg
 Continue prednisolone 30 mg daily for ten days
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21.  IPRATROPIUM BROMIDE
 Nebulised ipratropium bromide (0.5
mg 4-6 hourly) should be added to b2
agonist treatment for patients with
acute severe or life threatening
asthma
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22.  INTRAVENOUS MAGNESIUM
SULPHATE
 A single dose of IV magnesium sulphate
has been shown to be safe and effective
in acute severe asthma who have not
had a good initial response to treatment
 Consider magnesium sulphate in
 Acute severe asthma
 Life threatening or near fatal asthma
 Dose 1.2-2g iv infusion over 20minutes
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23.  INTRAVENOUS AMINOPHYLLINE
 IV aminophylline (5 mg/kg loading dose over 20
minutes
 then infusion of 0.5-0.7 mg/kg/hr).
 LEUKOTRIENE RECEPTOR ANTAGONISTS
 May be used but no studies have confirmed their
effecacy
 ANTIBIOTICS
 Routine prescription of antibiotics is not
indicated for acute asthma.
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24.  INTRAVENOUS FLUIDS
 Pt require rehydration and correction
electrolyte imbalance
 Patient Education
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26. Questions???
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