Transcript BRONCHIAL ASTHMA

BRONCHIAL ASTHMA
DEFINITION
Asthma is a chronic inflammatory lung disease
characterized by
symptoms of cough , wheezing , dyspnoe and
chest tightness that occur in paroxysms and are
related to specific triggering events
airway narrowing that is partially or completely
reversible
increased airway responsiveness to a variety of
stimuli
over the years the incidence is progressively increasing
 Several hypothesis have been proposed to explain the increased
frequency in all age groups
1—improved hygeine resulting in less exposure to infectious pathogens
and an imbalance in the normal immune response
2—increased indoor air pollution by
--recycled air from air conditions
--increased allergens—cockroaches , dust mites ,pets
--irritant gases
--cigarette smoke
3—increased incidence of early onset of respiratory viral infections
CARDINAL PATHOPHYSIOLOGICAL FEATURES
Airflow limitation
Airway hypersensitivity
Airflow limitation
Airflow limitation
Usually reverses spontanously or with treatment
Airway hyper responsiveness
Exaggerated bronchoconstriction to wide variety of
non specific stimuli like cold air and exercise
Airflow limitation
 Bronchial smooth muscle hypertrophy
 Mucosal edema
 Thickening of basement membrane
 Inflammatory cells in submucosal tissues :
--Oesinophils, lymphocytes,mast cells and
neutrophills
CLASSIFICATION
Bronchial asthma may be
 Allergic or extrinsic
 Non allergic or intrinsic
EXTRINSIC
INTRINSIC
Known external allergen
+ve skin test
↑ IgE
No known external allergen
-ve skin test
Normal IgE
Onset in childhood or early
adult life
Intermittant asthma
other allergens—hay fever
and eczema often present
Family h/o multiple allergens
Onset in older adults
Tendency to improve during
More continous
Other allergens uncommon
Family h/o allergens
uncommon
Usually progressive disease
PRECIPITATING FACTORS
Allergens
 Pollens
 Mold
 Dust
 Cockroaches
 Fur of animals
 Feathers of birds
Irritants
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air pollution
Tobacco smoke
Perfumes /sprays /deodrants
Strong odors from household chemical like paint
detergents like chlorox ,insectisides like raid
Other potential triggers
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Certain food
Feather pillows
NSAID
Sinus infections
GERD
Temp changes
Classification
Classification is based upon the following
 Improvement over the previous 2-4 weeks
 Current values of FEV1and FVC
 Number of exacerbation requiring oral steroids /
year
Classification
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Intermittant
Persistant
Moderate persistant
Severe persistant
Other classification
Exercise induced asthma
NSAID sensitive asthma
Nocturnal asthma
Adult onset
Occupational---triggered by condition in work
place
Clinical features
 Usually presents as attacks of wheezing , which
commonly occur following exercise and viral
infections
 Less severe symptoms are nocturnal coughing
and wheezing
 Some patients present with breathlessness
alone
SEVERE ASTHMA
Features of severe asthma are—
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Inability to speak complete sentence
Exhaustion
Resp rate < than 30 / min
Silent chest—severe bronchospasm prevents air entry
Cyanosis
Tachycardia < than 120 / min
Pulses paradoxus
INVESTIGATIONS
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Blood gases
CXR
CBC—increased oesinophils
Spirometry –this demonstrates reversible airflow
obstruction .FEV1 / FVC should be done before and after
bronchodilator----improvement of 15-20 %
 PFM
 Skin testing
FVC
Measures the volume of air exhaled over a
continous period of 6 seconds—this helps to
provide an indication of how much air the lungs
can hold
FEV1
Measures the speed of air exhaled in one second
Bronchoprovocation testing
inhaled methacholine
Inhaled histamine
Exercise challenge