Asthma

Asthma (Bronchial Asthma)

Asthma is a chronic respiratory disease characterized by inflammation of the airways. During exacerbations, bronchial smooth muscles contract, mucosal linings swell, and mucus production increases. This leads to airflow obstruction, resulting in wheezing, coughing, chest tightness, or shortness of breath.

While the exact pathophysiology remains unclear, contributing factors include allergies, genetics, environmental triggers, and body weight.

Classification of Asthma Severity and Symptoms

Patient Advice

• Avoid known triggers and allergens (e.g., pet dander, dust mites, pollen). Use air purifiers and wash bed linens regularly.
• Avoid taking herbal products, supplements, or foods without consulting a healthcare provider, as they may trigger asthma or interact with medications.
• Use medications as prescribed and maintain a symptom diary to monitor exacerbations.
• Exercise-induced bronchoconstriction can be prevented by using bronchodilators before physical activity, especially in cold or dry air.
• Annual flu vaccination and other recommended immunizations are encouraged.
• Be cautious with medications that may worsen asthma (e.g., beta-blockers, aspirin,NSAIDs).

When to See a Doctor

• Sudden worsening of symptoms
• Inadequate response to prescribed rescue medication (e.g.,SABA)
• Frequent exacerbations during light or routine activity

Treatment Options

1. Antiasthmatic & COPD Medications

Beta-agonists

• Short-acting (SABA): salbutamol, terbutaline – Effective for quick relief; can be used before exercise to prevent bronchoconstriction.
  Long-acting (LABA): formoterol, salmeterol – For maintenance therapy. Do not use LABAs alone without inhaled corticosteroids due to the risk of severe exacerbations.
  Common side effects: tremors, palpitations, metabolic disturbances, and cardiac issues.

Anticholinergics

• Ipratropium, tiotropium – Bronchodilation via inhibition of acetylcholine-mediated pathways.

Inhaled corticosteroids (ICS)

• Budesonide, ciclesonide, flunisolide, mometasone – Anti-inflammatory effects reduce airway sensitivity; maximum effect seen after 6–10 hours of use. Side effects: oral thrush, hoarseness, occasional coughing. Proper inhaler technique and oral hygiene are essential.

Cromones (Mast Cell Stabilizers)

• Cromolyn sodium, nedocromil sodium – Used for prevention of asthma exacerbations triggered by exercise or seasonal allergens.
  No serious side effects, but should taper off gradually under supervision.

Leukotriene-Receptor Antagonists (LTRAs)

• Montelukast, zafirlukast – Reduce vascular permeability and mucus secretion; inhibit cysteinyl leukotriene receptors (CysLT1).

Methylxanthines

• Theophylline, aminophylline, and doxofylline – Bronchodilators used to prevent exacerbations; may be added when asthma remains uncontrolled.
• Side effects: insomnia, palpitations, restlessness, nausea, seizures. Requires close monitoring due to narrow therapeutic index.

Anti-IgE Monoclonal Antibody

• Omalizumab – Exerts its effect by blocking IgE from binding to immune cells that release inflammatory mediators responsible for asthma exacerbations. It is used for moderate-to-severe allergic asthma.
• Administered subcutaneously in healthcare settings. Caution: observe for severe allergic reactions (anaphylaxis) post-injection.

Anti-IL-5 Agents (Eosinophil-targeted therapy)

• Benralizumab, mepolizumab, reslizumab – Used in eosinophilic asthma not responding to standard treatment.
• Mepolizumab: May increase risk of shingles; pre-vaccination recommended.
• Reslizumab: Observe for anaphylaxis for at least 20 minutes post-injection. Not recommended if patient has parasitic infections or ongoing infections.

α- and β2-Adrenoreceptor Agonists (e.g., epinephrine)

• Used only in emergencies such as anaphylaxis or angioedema where inhaled bronchodilators are unavailable or ineffective.

2. Corticosteroids

• Hydrocortisone, prednisolone, dexamethasone – Short-term use for acute exacerbations when other medications are insufficient.
  Caution: Only under medical supervision due to serious systemic side effects.

3. Bronchial Thermoplasty

• A non-drug treatment using radiofrequency to reduce airway smooth muscle mass, minimizing bronchial hyperreactivity.
  Indicated for patients >18 years with severe asthma not controlled by standard inhaled medications.

4. Antihistamines & Antiallergics

• Cetirizine, Levocetirizine, Loratadine, Fexofenadine, Ketotifen, Dexchlorpheniramine, Promethazine, Triprolidine – Used to manage respiratory allergies that can trigger or worsen asthma symptoms.

5. Allergen Immunotherapy (AIT)

• Indicated for moderate-to-severe allergic asthma unresponsive to pharmacologic therapy.
  Involves administration of gradually increasing doses of allergens via:
  • Subcutaneous Immunotherapy (SCIT)
  • Sublingual Immunotherapy (SLIT)
    Proven effective for pollen, dust mites, and animal dander allergies. Requires medical supervision; benefits usually start after 1 year and may last 3–5 years.