Asthma Flashcards
What are the two main precipitators of allergic asthma? How do recruited leukocytes contribute?
- Mast cell activation
- Release of inflammatory mediators
- Initiate second wave of inflammatory reactions
How does chronic airway inflammation affect responsiveness to airway irritants?
Asthmatic episodes can now be triggered in the absence of allergens
Clinically, what are 2 features of an asthmatic airway? How are these measured?
Bronchial hyperreactivity to aerosolized histamine or adenosine - FEV
Increased eosinophils below epithelium - Sputum or lavage
There are 2 reaction phases associated with asthma, the early and late reactions. How is each treated / prevented?
Early - Prophylactic corticosteroids, cromolyn, Beta-2-agonists
Late - Inhaled corticosteroids
What is the class of drug used for quick relief of asthma symptoms?
Beta-2- agonists
What are the 3 anti-inflammatory types of drugs used for the long term treatment of asthma?
Corticosteroids
Cromolyn
Leukotriene antagonists
What are 2 types of agents used for long term prevention of airway constriction?
Long acting beta 2 receptor antagonists
Methylxanthines
What are the 2 leukotrienes associated with asthma?
LTB and LTD
How does LTB affect asthma? How dies LTD affect asthma?
LTB - Increased neutrophil chemotaxis
LTD - Increased capilary permeability, bronchial constriction and eosinophil chemotaxis
What are 2 oral steroids that can be used for the treatment of asthma?
Prednisone
Methylprednisolone
What are the 3 main mechanisms by which steroids work for asthma?
Inhibition of PLA2 expression
Reduced synthesis of chemotactic factors
Inhibition of cytokine expression
Why are steroid not immediately effective for the treatment of asthma?
They require protein synthesis
What is the major leukotriene associated with bronchoconstriction and edema of the airway? What produces it?
LTD4
Made by mast cells
Which leukotriene is chemotactic fo eosinophils? Which is chemotactic for neutrophils?
LTD (eosinophils)
LTB (neutrophils)
What is the enzyme target of zileuton? What products of this enzymes are reduced?
5-lipoxygenase
LTB and LTD
Zileuton is associated with what organ toxicity? What else should you be aware of when using zileuton?
Liver
Inhibits CYP enzymes
What are 2 drugs provided as examples of leukotriene receptor antagonists?
Montelukast
Zafirlukast
What is aspirin induced asthma? What is the likely mechanism? Is this a form of asthma allergy?
Bronchoconstriction resulting from aspirin usage (not allergy)
Increased synthesis of leukotrienes vs. prostaglandins from arachidonic acid
No, not allergy
What are 2 examples of non-steroid inhaled long term controller of asthma? What is the proposed mechanism?
Cromolyn
Nedocromyl
Block mast cell degranulation (block Ca++ channels)
Block Cl channels
What is the mechanism by which beta-2 agonists treat asthma?
Stimulate adenyl cyclase and cAMP, lead to bronchial smooth muscle relaxation
What are 3 beta-2 agonists used to treat asthma?
Albuterol
Metaproterenol
Pirbuterol
What are 2 long acting beta-2 agonists used to treat asthma?
Salmeterol
Formoterol
What is a muscarinic antagonist used to treat asthma? What type of response does it inhibit? How does it compare to the beta-2 agonists?
Ipratropium
Inhibits the parasympathetic responses associated with asthma
Slower, less effective
What is a methylxanthine used for the treatment of asthma? How does it work?
Theophilline
Block phophodiesterase, increasing cAMP and thus relaxation of bronchial smooth muscle
