9-asthma Flashcards
what s the asthma?
A chronic inflammatory disease of the respiratory system characterized by bronchial hyperresponsiveness, episodic exacerbation (asthma attacks), and reversible airflow obstruction. Manifests with reversible cough, wheezing, and dyspnea.
the obstruction of asthma is due to a combination of what 3 factors?
- Mucosal inflammation with inflammatory cells, (eosinophils, mast cells and Th2 lymphocytes)
- Neural hyperresponsiveness
- Smooth muscle hypertrophy and thickening of the basement membrane, the space below the epithelium
how mucosal inflammation seen in asthma occurs?
Overexpression of Th2-cells → inhalation of antigen results in production of cytokines (IL-3, IL-4, IL-5, IL-13) → activation of eosinophils and induction of cellular response (B-cell IgE production) → bronchial submucosal edema and smooth muscle contraction → bronchioles collapse
what is the pathophysiology of asthma?
- Inflammation of the airways with eosinophils, mast cells and lymphocytes
- This immune dysregulation is driven by pollution, allergens and viruses
- The inflammation leads to loss of the epithelium: ↑ mucus and bronchoconstriction (narrowing of the airway)
- Intermittent/ episodic
asthma is drive by TH2 or TH1?
Asthma is generally characterized as an inflammatory disease driven by T-helper type 2 (Th2-cell) that manifests in individuals with a genetic predisposition
what are the typical features of inflammation seen in asthma?
The inflammation has typical features of an allergic response, such as the thickening of the basement membrane and the detection of eosinophils.
what level of the bronchial tree is mainly affected in asthma?
symptoms are primarily caused by inflammation of the terminal bronchioles, which are lined with smooth muscle but lack the cartilage found in larger airways.
endobronchial obstruction of asthma is caused by?
- -Bronchospasm
- -Mucosal edema
- -Hypertrophy of smooth muscle cells
- -Increased mucus production
what is the specific pathophysiology of allergic asthma
IgE-mediated type 1 hypersensitivity to a specific allergen; characterized by mast cell degranulation and release of histamine after a prior phase of sensitization
what is the specific pathophysiology of non-allergic asthma?
- -Irritant asthma: irritant enters lung → ↑ release of neutrophils → submucosal edema → airway obstruction
- -Aspirin-induced asthma: NSAID inhibition of COX-1 → ↓ PGE2 → ↑ leukotrienes and inflammation → submucosal edema → airway obstruction
what are the 2 principles of asthma treatment?
- Reduce inflammation (anti-inflammatory)
2. Open the airways(bronchodilation)
maintenance therapy of asthma consist of?
Inhaled corticosteroids (anti-inflammatory drugs) given by inhalers
e.g. Beclomethasone, budesonide, fluticasone
These are usually given along with Long-acting bronchodilator therapy
Long-acting β2 agonists (LABA) e.g. Salmeterol, formoterol
examples of long-acting β2 agonists
Salmeterol, formoterol
examples of inhaled glucocorticoids?
Beclomethasone, budesonide, fluticasone
what is the MOA of steroids in asthma?
- -reduce mucous production by goblet cells
- -restore epithelial cell growth
- -increases numbers of beta receptors
- -inhibits recruitment of inflammatory cells and reduce bronchial hyperactivity
acute symptoms of asthma are treated by what medications?
- Inhaled short acting β2 agonists e.g. Salbutamol, Terbutaline
- Inhaled anticholinergics e.g. Ipratropium
how anticholinergic drugs work in asthma?
inhibit Ach binding to muscarinic (M3) receptors
what are the symptoms of asthma?
• Cough (often nocturnal)
• Wheeze (intermittent)
• Shortness of breath (reversible)
• Typically the first onset in childhood
• A strong relationship with rhinitis and eczema (allergy
Persistent, dry cough that worsens at night, with exercise, or on exposure to triggers/irritants (e.g., cold air, allergens, smoke)
End-expiratory wheezes
Dyspnea
Chest tightness
Chronic allergic rhinitis with nasal congestion
what is the characteristic feature of cough of asthma
Persistent, dry cough that worsens at night, with exercise, or on exposure to triggers/irritants (e.g., cold air, allergens, smoke)
why the cough of asthma is worse at night?
- Plasma adrenaline levels decrease 4 am
- Plasma cortisol levels decrease 12 am
- Nocturnal symptoms 2-3 am