Asthma and COPD Overview

Asthma is a respiratory condition characterized by inflammation and narrowing of the airways, resulting in symptoms like shortness of breath, wheezing, chest tightness, and coughing.

Asthma is caused by an inflammatory response within the airways. This inflammation can be triggered by various factors, such as allergens, viruses, cold air, or exercise.

Inhaled allergens like dust mites, cockroach droppings, animal dander, molds, and pollen can trigger an allergic response in individuals with asthma.

The tendency to produce IgE antibodies, which play a role in allergic reactions, is often inherited.

A rapid allergic response to allergens is characterized by the release of histamine and other inflammatory mediators from mast cells, leading to airway narrowing and increased mucus production.

A late-phase allergic reaction occurs several hours after exposure to an allergen. It's characterized by additional inflammation and airway narrowing, making breathing even more difficult.

Inhaled corticosteroids are a type of medication used to manage asthma. They work by reducing inflammation in the airways, making it easier to breathe.

The bronchial airways are the tubes that carry air to and from the lungs. In asthma, these airways become narrowed due to inflammation and muscle contraction.

Sympathomimetic agents (like albuterol) are the first-line treatment for acute asthma attacks. They relax airway muscles, allowing easier breathing.

Long-acting beta-2 agonists (LABAs) like salmeterol are not for acute asthma attacks. They are used for long-term control to prevent attacks.

Inhaled corticosteroids (ICS) like fluticasone are used to reduce inflammation in the airways, which is the root cause of asthma symptoms.

Beta-2 agonists work by increasing cAMP levels in the airways, which leads to muscle relaxation.

Albuterol and other short-acting beta-2 agonists (SABAs) work quickly but their effects only last for a few hours.

Methylxanthines like theophylline are bronchodilators that work by blocking the breakdown of cAMP in the airways.

Anticholinergics like ipratropium block the action of acetylcholine, preventing bronchoconstriction.

Asthma treatment aims to prevent attacks, reduce inflammation, and provide quick relief when needed.

A late-phase allergic reaction, also known as the "late asthmatic response", occurs 3 to 6 hours after exposure to an allergen. It is characterized by persistent bronchoconstriction, inflammation, and increased bronchial reactivity. This response is caused by the influx of inflammatory cells into the airways.

The late-phase allergic reaction is mediated by specific cytokines produced by TH2 lymphocytes, primarily interleukin 5, interleukin 9, and interleukin 13. These cytokines influence various inflammatory processes within the airways.

One of the main roles of these cytokines is to attract and activate eosinophils, which are a type of white blood cell involved in inflammation. They contribute to the airway narrowing and wheezing associated with asthma.

Interleukin 5, 9, and 13 also stimulate the production of IgE antibodies by B lymphocytes. IgE antibodies are the primary trigger of immediate allergic reactions, leading to the release of histamine and other inflammatory mediators.

These cytokines, particularly interleukin 13, also stimulate the production of mucus by the bronchial epithelial cells. Increased mucus secretion contributes to airway obstruction and difficulty breathing.

Asthma is generally categorized into mild and more severe forms based on symptom frequency and severity. Mild asthma is characterized by occasional symptoms triggered by specific factors, while more severe forms involve frequent attacks and chronic airway narrowing.

The treatment of asthma aims to both relieve acute bronchoconstriction (quick relief) and reduce inflammation (long-term control). Bronchodilators are used for immediate relief, while antiinflammatories are essential for long-term management.

The late-phase allergic reaction contributes to increased responsiveness in the airways, particularly in asthma. This increased responsiveness can be managed by reducing exposure to allergens and using anti-inflammatory medications, especially inhaled corticosteroids.

Inhaled corticosteroids (ICS) are the first-line therapy for moderate to severe asthma. They work by reducing inflammation in the airways, making breathing easier.

Inhaled corticosteroids work by interfering with the production of inflammatory substances like prostaglandins and leukotrienes.

Inhaled corticosteroids are considered safe for most adults and children with moderate to severe asthma.

One potential side effect of inhaled corticosteroids is oral candidiasis (thrush) due to the deposition of drug droplets in the pharynx.

Patients using inhaled corticosteroids can help prevent oral thrush by gargling with water and spitting after each treatment.

Inhaled corticosteroids are often used early in asthma management to prevent the progression of the disease.

Daily systemic prednisone is used in severe asthma cases as a short-term treatment.

Switching from daily systemic prednisone to inhaled corticosteroids or alternate-day oral therapy is a common approach to manage severe asthma.

While inhaled corticosteroids slow growth by 1 cm in the first year of treatment, the impact on adult height is minimal.

Systemic corticosteroids, like prednisone, are usually administered earlier in the day because they can suppress the adrenal glands, which normally release cortisol in the morning.

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation that is not fully reversible with treatment, unlike asthma.

COPD is generally considered poorly responsive to high-dose inhaled corticosteroids (ICS) therapy, unlike asthma.

Oral or inhaled corticosteroids are most effective when administered in the late afternoon for the prevention of nocturnal asthma.

Long-term use of inhaled corticosteroids can cause mild growth retardation in children.

Short-acting β-agonists, like albuterol, or an anticholinergic drug, like ipratropium bromide, are often used to relieve acute symptoms of COPD.

Long-acting bronchodilators like LABAs (e.g., Salmeterol) and long-acting anticholinergics (e.g., Tiotropium) are recommended for patients with persistent exertional dyspnea and activity limitations due to COPD.

Theophylline can be helpful in treating COPD because it improves diaphragm function, helping patients breathe better. However, be cautious as beta-blockers can reduce its effectiveness.

Roflumilast is a non-methylxanthine medication used in COPD. It works by inhibiting phosphodiesterase, improving lung function and reducing flare-ups.

Inhaled corticosteroids (ICS) are less commonly used for COPD compared to asthma because they offer lower efficacy and carry an increased risk of bacterial pneumonia. However, they are recommended for severe cases and patients with recurrent flare-ups.

Patients with two or more COPD exacerbations should receive daily ICS therapy. Daily azithromycin, which has anti-inflammatory and immunomodulatory effects, can also significantly reduce the frequency of exacerbations.