Asthma Management and Treatment

Asthma

• A chronic, reversible obstructive lung disease
• Characterized by wheezing and shortness of breath
• Due to bronchial hyper-reactivity and inflammation
• Often seen in patients with allergies
• Severity ranges from mild to life-threatening

Asthma Management

• First Step: Identifying and removing triggers
• Goal: Improve airflow and expiration by bronchodilation or reducing inflammation
• Triggers: Allergens, environmental factors

Bronchodilators

• Used to reverse bronchial smooth muscle constriction, improving airflow
• β2-Adrenergic Agonists:
  • Stimulate β2 receptors in lungs, leading to bronchial dilation
  • Types:
    • Short-acting (SABAs): Used for acute exacerbations
    • Long-acting (LABAs): Daily use for moderate to severe asthma
• Muscarinic Antagonists:
  • Block muscarinic receptors, preventing bronchoconstriction
  • Types:
    • Short-acting (SAMAs): Used as adjunctive therapy for acute exacerbations
    • Long-acting (LAMAs): Used for maintenance therapy
• Theophylline:
  • Phosphodiesterase (PDE) inhibitor and adenosine receptor antagonist, promoting bronchodilation
  • Less common due to adverse effects
• Intravenous Magnesium Sulfate:
  • Used in emergencies, causes bronchodilation by inhibiting calcium influx
  • Administered as a single intravenous bolus dose

Anti-Inflammatory Drugs

• Inhaled Corticosteroids (ICS):
  • First-line maintenance drug for asthma
  • Suppress inflammation in bronchial tubes, reducing swelling
  • Types: Beclomethasone, budesonide, fluticasone
• Oral Corticosteroids:
  • Used for severe asthma exacerbations to reduce inflammation
  • Examples: Prednisone
• Intravenous Corticosteroids:
  • Used in management of severe asthma exacerbations

Other Drugs

• Antileukotrienes (Leukotriene Receptor Antagonists [LTRAs]):
  • Used for mild to moderate asthma symptoms as secondary drugs
  • Inhibit the action of leukotrienes
  • Types: montelukast, zafirlukast, zileuton
• Cromolyn Sodium:
  • Inhaled prophylactically before exposure to triggers
  • Used for long-term maintenance therapy
  • Mechanism not fully understood, likely inhibits mediator release or reduces bronchus sensitivity
• Biologics:
  • Monoclonal antibody drugs used for allergic asthma
  • Examples: omalizumab, dupilumab, mepolizumab, reslizumab, benralizumab, tezepelumab

Stepwise Asthma Management

• Step 1: As-needed SABA
• Step 2: ICS added for persistent symptoms
• Step 3: ICS/LABA combination
• Step 4-5: Consider leukotriene inhibitors, cromolyn, theophylline, or biologics

Emergency Department Management

• Step 1: Inhaled SABA and ipratropium
• Step 2: Systemic corticosteroids
• Step 3: IV magnesium
• Step 4: IV epinephrine or terbutaline
• Severe Asthma: Monitor vital signs, provide oxygen, consider BiPAP or intubation

Patient Example: QS

• 19-year-old college student with worsening asthma symptoms
• Using albuterol inhaler frequently
• New prescription: Inhaled corticosteroid for regular use, continue albuterol as needed

Asthma Management

• Asthma is a chronic condition characterized by airway inflammation and hyper-reactivity leading to episodic airway obstruction.
• Bronchodilators and corticosteroids are the primary treatment options for asthma.
• Inhaled β2 agonists (e.g., albuterol) are first-line bronchodilators in adults, acting by stimulating β2 receptors on bronchial smooth muscle.
• Inhaled muscarinic antagonists (e.g., ipratropium) block muscarinic receptors, inhibiting bronchoconstriction.
• Methylxanthines (e.g., theophylline) are phosphodiesterase inhibitors and adenosine receptor antagonists, used as alternative bronchodilators.
• Magnesium relaxes smooth muscle and is used only in acute severe asthma.
• Corticosteroids reduce airway inflammation, thereby reducing swelling and bronchoconstriction.
• Inhaled corticosteroids are often used early in asthma management alongside short-acting β2 agonists.
• Antileukotrienes (e.g., montelukast) block cysteinyl leukotriene receptors and inhibit leukotriene production, reducing airway inflammation.
• Cromolyn is a secondary agent that reduces T-cell secretion of inflammatory mediators.
• Biologics (e.g., omalizumab) are monoclonal antibodies targeting inflammatory mediators like IgE, IL-4, and IL-5, used in severe cases.
• Asthma management is stepwise, progressing with disease severity, drug tolerance, and contraindications.
• Treatment begins with "as-needed" short-acting β2 agonists, followed by inhaled corticosteroids, then long-acting β2 agonists, antimuscarinics, and oral corticosteroids.
• Severe asthma may require intravenous corticosteroids, magnesium, and epinephrine.
• Close monitoring of vital signs, including partial pressure of arterial oxygen (PaO2) and carbon dioxide (PaCO2), is crucial.
• Patients may require continuous oxygen and intubation in severe cases.