Respiratory System Overview: Asthma and Disorders

Respiratory Disorders Overview

• Major respiratory disorders include asthma, chronic obstructive pulmonary disease (COPD), allergic rhinitis, and cough.

Asthma

• Chronic inflammatory condition affecting airways, leading to bronchoconstriction, causing symptoms such as shortness of breath, cough, chest tightness, wheezing, and rapid respiration.
• Triggering factors include allergens, exercise, stress, and respiratory infections.

Pathophysiology

• Airflow obstruction arises from:
  • Bronchial smooth muscle contraction
  • Bronchial wall inflammation
  • Increased mucus secretion
  • Underlying airway hyperresponsiveness

Therapy Goals

• Key objectives are reducing symptom frequency and intensity, and improving patient quality of life.
• Patients must have quick-relief medication for acute symptoms.
• Long-term treatment focuses on reversing and preventing airway inflammation.

Drug Delivery Methods

• Methods include nasal mucosa delivery, inhalation to the lungs, or oral/parenteral routes for systemic absorption.
• Local delivery (inhalers, nasal sprays) minimizes systemic side effects.

β2 -Adrenergic Agonists

• Directly relax airway smooth muscle for quick relief of asthma symptoms.
• Short-acting β2 agonists (SABAs), e.g., albuterol and levalbuterol, provide relief within 5 to 30 minutes, lasting 4 to 6 hours.

Quick Relief with SABAs

• Essential for all asthma patients; however, not anti-inflammatory.
• Appropriate for intermittent asthma or exercise-induced bronchoconstriction.

Long-Term Control with LABAs

• Long-acting β2 agonists (LABAs) like salmeterol and formoterol provide bronchodilation for at least 12 hours.
• LABAs should not be used as monotherapy in chronic asthma; they require combination with inhaled corticosteroids (ICS).

Inhaled Corticosteroids (ICS)

• The first-line treatment for long-term asthma control.
• Effective for all degrees of persistent asthma in children and adults.
• ICS reduce airway inflammation and hyperresponsiveness when used regularly.

Alternative Drugs for Asthma Treatment

• Used when patients have poor control or adverse reactions to conventional therapies.
• Should be used alongside ICS, not as monotherapy.

Leukotriene Modifiers

• Work by inhibiting leukotriene production and blocking their receptor effects.
• Approved for asthma prevention; ineffective for immediate bronchodilation.

Cromolyn

• Prophylactic agent that prevents mast cell degranulation, but not useful for acute attacks.
• Requires frequent dosing, which can affect adherence.

Cholinergic Antagonists

• Ipratropium is useful for those intolerant to SABAs and provides additional benefit in acute situations.

Theophylline

• A bronchodilator with potential anti-inflammatory effects, now less commonly used due to its narrow therapeutic index.
• Requires monitoring and has significant drug interactions.

Monoclonal Antibody (Omalizumab)

• Targets human IgE to reduce allergic responses; used in patients with severe persistent asthma not controlled by other therapies.
• High cost and subcutaneous administration every 2 weeks limit its use; risk of rare anaphylactic reactions exists.

Case Study Context

• A 12-year-old girl with asthma develops cough and wheezing after exposure to a horse riding stable, highlighting the necessity for quick-relief medication in emergencies.

This quiz covers key concepts related to the respiratory system, focusing on respiratory disorders such as asthma, chronic obstructive pulmonary disease (COPD), and allergic rhinitis. Understand the pathophysiology and symptoms associated with these conditions to deepen your knowledge of respiratory health.