Asthma Flashcards
What is Asthma?
Asthma is a Type I hypersensitivity which is characterized by reversible acute episodes of airway obstruction due to inflammation and muscle hyperactivity and of chronic inflamation of the airways which is recurrent and reversible bronchospasm. It may be caused by other alergic disorders like hay fever.
Are the episodes of airway obstruction chronic, or the disease?
The disease is chronic, but the episodes of airway obstruction are acute.
What is the etiology of asthma?
Asthma is a complex trait Type I Hypersensitivity which involves both genetic and environmental factors.
What are some common triggers of asthma?
Allergens, Airway Irritants, Exercise, Strong Odours, Cold Air.
Is cold air an asthma trigger on its own?
Not typically. Usually, cold air will act as a secondary trigger post asthma episode.
What are the two response phases called in asthma?
Acute-Phase Response, Late-Phase Response
Explain the Acute-Phase response in asthma?
First, prior sensitization to an allergen must occur (Type I hypersensitivity). Upon subsequent exposures, allergens bind to IgE coated mast cells, releasing mediators from the cells and causing inflammation. Intracellular junctions open allowing allergens to enter the submucosa. Increased permability and increased mucus secretions lead to edema of the airways. The perriferal nervous system (PNS) stimulates bronchospasm leading to dyspnea and wheezing. The airway constricts as a compensatory mechanism. The acute phase last up to 1 hour.
Explain the Late-Phase response of Asthma?
The late-phase response peaks in 4 - 8 hours and can last for a few days or even weeks. During the Late-Phase response the manifestations of acute phase persist as the patient undergoes a self-sustaining cycle of exacerbation. There is an influx of inflammatory cells causing epithelial damage, decreased mucocillary function, and hyperresponsive airway which reacts to new triggers like cold air. The patient goes through frequent and severe episodes.
In Asthma, bronchoconstriction occurs via which receptors?
Alpha Adernergic receptors (Adrenalin)
In Asthma, which receptors cause bronchodilation?
Beta Adernergic receptors
What act as secondary mediators in an Asthmatic?
cAMP mediates
What are the manifestations of Asthma?
Asthma has a spectrum of manifestations. The most common are: Dyspnea, Wheezing, Immobilzation, Brochospasm and Coughing, Increased respiratory effort, Ventilatory Compromise
What two distinctive features will an individual with prolonged long-term increased respiratory effort present with?
Barrel chest and Pursed lip exhalation.
When would you see immobilization as a manifestation in an Asthma patient?
In an acute extreme attack.
What is the physiologic reason for an Asmatic to cough and bronchospasm?
To clear the air way of expectorate.
