======Asthma======

  * Chronic inflammatory disease of respiratory tree to various sensitizing stimuli resulting in reversible airway obstruction
  * Characterized by
    * Bronchial hyperresponsiveness
    * ?


=====Types=====
  * Allergic 
    * Atopic
    * Extrinisic
    * Most common form
    * Triggered by inhaled antigens (dust mites, pollen, pet dander, mold)
    * Biologics
    * Immunologic based
  * Non-allergic (intrinisic)
    * non-atopic
    * intrinisic* 10% of asthmatics
    * triggered by factors not related to allergies
      * exercise
      * cold/dry allergic
      * smoke
      * viruses
      * stress/anxiety
      
=====Immunology=====
  * Main immunologic cells
    * Macrophages
    * Dendritic cells
  * Eosinophil
  * Immunity
    * Innate
    * Adaptive
      * Humoral (B cells)
        * Memory
        * Effector (plasma)
        * Antigen presenting cell
      * Cell-mediated (T cells)
        * T helper cells (CD4): mainly TH2
          * IL-4 and IL-13 (dupilumab)
            * indications
              * adults
              * moderate-to-severe atopic dermatitis (eczema)
          * IL-5 (mepolizumab, benralizumab, reslizumab)
            * indications
              * age 18 and above
              * severe persistent asthma, refractory to other treatment
              * eosinophilia, but not elevated IgE
            * side effects (OI: herpes zoster with mepolizumab)
          * IgE (omalizumab)
            * indications
              * age 12 and above
              * moderate to severe persistent asthma, refractory to other treatment
              * serum IgE elevated (dose by IgE and weight)
            * only administered in health care setting
            * possible anaphylaxis
        * Cytotic T-cells (CD8)

=====Diagnosis=====
  * Pattern of symptoms and response to therapy
  * Spirometry and/or PFTs + BD response (≥12%)
    * FEV1/FVC, FEV1, FVC
    * TLC, DLCO
  * Challenge testing
    * Exercised induced bronchoconstriction & chronic cough
      * Exercised
      * Cold air
      * Methacholine
  * Fraction of exhaled NO
    * High values of FENO in asthma that returns to normal after treatment with glucocorticoids
    * Eosinophilic inflammation in airways stimulates airway epithelial cells to produce NO
  * Sputum eosinophiles
    * Charcot leyden crystals
    * Curschmann's spirals

=====Treatment=====
  * Anti-inflammatory medications
    * Corticosteroids: PO, inhaled, IV, IM
  * Direct bronchodilators (short and long acting)
    * b2-agonists (increases cAMP): salbutamol, albuterol, levalbuterol
    * anti-cholinergics (M3 receptor in airway smooth muscle)
      * helpful/recommended in acute setting
      * ipratropium bromide
    * methylxanthines
      * theophylline
      * aminophylline (short acting)
    * ?
  * Mast-cell stabilizers
  * Leukotriene inhibitors
    * Zileuton (Zylfo): leukotriene synthesis inhibitor
    * Monteleukast (Singulair): leukotriene receptor antagonist
  * Combination medications
    * Dulera: mometasone furoate and formoterol fumarate
    * Symbicort: budesonide and formoterol fumarate
    * Advair: fluticasone and salmeterol
  * Bronchial thermoplasty: approved for severe persistent refractory asthma, intrinisic and extrinisic (but other options better for extrinsic)

=====Caution=====
  * aspirin
  * ACE inhibitor
  * permissive hypercapnia