Asthma

Objective

At the end of this PDF Notes, student will be able to

•        Define Bronchial asthma

•       Explain the pathophysiology of Bronchial asthma

•       Describe the symptoms of Bronchial asthma

Asthma

•       Disorder of the respiratory system that leads to episodic difficulty in breathing

•       Chronic inflammatory disorder of the airways in which many cells and cellular elements play a role

•       Mast Cells, Eosinophils, T Lymphocytes, Macrophages, Neutrophils , Epithelial Cells

Bronchial Asthma

ü  Also called reversible airway obstruction

ü  Clinical syndrome characterized by recurrent bouts of bronchospasm

ü  Increased responsiveness of the tracheobronchial smooth muscles to various stimuli

ü  Results in narrowing of the airway

ü  Chronic inflammatory disorder with reversible airflow obstruction

ü  Inflammation of bronchial wall mediated by eosinophils, mast cells & lymphocytes

ü  Hyper-responsiveness of bronchi – narrow readily with stimuli

ü  In late stages – irreversible

Etiology of Asthma

Extrinsic or allergic

ü  History of `atopy` in childhood

ü  Family history of allergies

ü  Positive skin test

ü  Raised IgE level

ü  Below 30 years of age

ü  Less prone to status asthmaticus

Intrinsic or idiosyncratic

ü  No family history of allergy

ü  Negative skin test

ü  No rise in IgE level

ü  Middle age onset

ü  Prone to status asthmaticus

Triggers

Drugs

Aspirin, ibuprofen and other prostaglandin synthetase inhibitors, beta blockers

 Foods

Nuts, fish, sea food, dairy products, food colouring

Other industrial chemicals

Wood or grain dust, cotton dust, cigarette etc

Miscellaneous

Cold, exercise, hyperventilation ,viral respiratory tract infections, emotion or stress

Pathophysiology of Asthma

Main features of asthma:

–     Hypertrophy of bronchial smooth muscle

–     Hyperplasia of epithelial cells

–     Mucus gland hypertrophy

–     Airway oedema

–     Acute bronchoconstriction

–     Impaired mucociliary clearance

•      Early exposure to

            – Allergens

– Viral infections

– Diet induced

•      Early onset: Atopic

           -Positive family history

-Readily form IgE to common allergens react with mast cells on surface & activate IgE – histamine release

-Many more mediators

v  Changes in the airway

ü  Epithelial shedding

ü  Airway hyper-responsiveness

ü  Microvascular leakage – exudate mucus plugging

ü  Neuronal imbalance – bronchoconstriction

v  IgE-antibody-mediated reaction on the surface of the mast cell leads to release of mast cell components

v  Histamine – triggers rapid bronchoconstriction

v  Eosinophils release LTC4 and PAF

v  Epithelial damage and thick viscous mucus produced causing deterioration in lung function

v  Epithelial damage

v  Increases access of various irritants to the cholinergic receptors,

v  Bronchoconstriction mediated by the parasympathetic nervous system

Signs and Symptoms of Asthma

•      Persistent cough

•      Dyspnoea – difficulty in breathing

•      Wheezing – a high pitched noise due to turbulent airflow through a narrowed airway

•      Tightness of chest

•      Shortness of breath

•      During attacks – fatigue, cyanosed, lethargic, confused, breathless, rapid breathing (> 30 breaths/minute)

Clinical Features of Asthma

•      Episodic or chronic

•      Triad of:

        – Dyspnea (difficulty in breathing)

– Wheezing (additional sounds)

– Cough (persistent)

•      Productive sputum

•      Others

           Tachycardia

Pulsus paradoxus

Sweating

Cyanosis, bradycardia in severe cases

Silent chest

Diagnosing Bronchial Asthma

Medical History and Physical Examination

Diagnosing asthma begins with a detailed medical history and physical examination. Your healthcare provider will ask about your symptoms, family history, and exposure to potential triggers.

Lung Function Tests

Lung function tests, such as spirometry and peak flow measurements, are essential for confirming the diagnosis. These tests assess how well your lungs are functioning and the degree of airway obstruction.

Management and Treatment

Medications

Asthma management often involves medications, including bronchodilators to relax the airways and corticosteroids to reduce inflammation. Inhalers are commonly used to deliver these drugs directly to the lungs.

Lifestyle Changes

In addition to medication, certain lifestyle changes can help control asthma. This may include identifying and avoiding triggers, maintaining a healthy weight, and staying physically active.

Living with Bronchial Asthma

Coping Strategies

Living with asthma requires adopting coping strategies to ensure a good quality of life. Education about the condition, a strong support system, and a written asthma action plan are all essential for managing asthma effectively.

SUMMARY

•      Chronic inflammatory disorder with reversible airflow obstruction

•      Inflammation of bronchial wall mediated by eosinophils, mast cells & lymphocytes

•      IgE-antibody-mediated reaction

•      Release of mast cell components which  triggers rapid bronchoconstriction

•      Persistent cough, recurrent episodes of difficulty in breathing associates with wheezing, chest tightness, shortness of breath, abnormal lung function are the common symptoms

Asthma PDF Notes