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Bronchial asthma: Pathophysiology, Clinical features, Management

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    Bronchial asthma is a chronic inflammatory condition of the respiratory tract characterized by episodic exacerbations of hyperresponsiveness and reversible airway obstruction.


    The early phase of bronchial asthma occurs within 15-30 minutes and is marked by bronchoconstriction, primarily due to the release of histamine, leukotrienes, and bradykinin. The late phase occurs after 4-12 hours and is characterized by airway inflammation and increased secretion.

    bronchial asthma

    Asthma triggers

    Asthma triggers encompass a variety of factors:

    • Allergens: including house dust mites, mold, pollen, and certain drugs.
    • Environmental factors: such as smoke, dust, strong odors/fumes, and exposure to cold air.
    • Physical activity.
    • Emotional triggers.

    Clinical features


    • Intermittent dry cough, recurrent or nocturnal episodic cough
    • Wheezing (in acute exacerbation or advanced asthma)
    • Breathlessness or shortness of breath
    • Chest tightness (only expressed by older children)
    • Nonspecific
      • Fatigue
      • Exercise intolerance.
      • Poor sleep

    General examination

    • Dyspneic
    • Prominent accessory muscles of respiration
    • Air hunger, cyanosis
    • Flaring of alae nasi
    • Altered sensorium in acute exacerbations.

    Examination of chest

    • Inspection: Tachypnea, chest hyperinflated, presence of subcostal, suprasternal, and intercostal recessions
    • Palpation: Reduced chest expansion but central trachea
    • Percussion: hyper-resonant
    • Auscultation: Vesicular breath sound with prolonged expiration, rhonchi present.

    Differential Diagnosis

    • Bronchiolitis
    • GERD
    • Hypersensitivity pneumonitis
    • Foreign Body inhalation
    • Cystic fibrosis


    Generally, diagnosis is based on clinical, but laboratory support has little role.

    Clinical evidence

    • Presenting complaints like recurrent cough, breathlessness, wheezing, etc.
    • History of asthma

    Laboratory Investigation

    • PEFR: Morning-evening variation>20%
    • Low FEV1
    • FEV1/FVC<0.8
    • Bronchodilator response (beta agonist): Improvement in FEV1≥12%
    • Exercise challenge: Worsening in FEV1 ≥ 15%
    • Chest X-ray: hyperinflation of lungs (low flat diaphragm and more horizontal ribs) and tubular heart
    • Absolute Eosinophil Count (AEC) test: may be increased.
    • Allergy test but limited role



    • Maintain normal activity.
    • Prevent sleep disturbance.
    • Prevent chronic asthma symptoms.
    • Prevent severe exacerbation.
    • Less or No side effects from drug therapy


    • Beta 2 agonist (inhaled): salbutamol, terbutaline
    • Inhaled anticholinergics: Ipratropium bromide
    • Short course systemic steroid: oral prednisolone, Methyl prednisolone.

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