{"id":4690,"date":"2025-08-14T20:37:05","date_gmt":"2025-08-15T00:37:05","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/?post_type=chapter&p=4690"},"modified":"2025-12-07T23:23:50","modified_gmt":"2025-12-08T04:23:50","slug":"pathophysiology-of-intrinsic-asthma","status":"web-only","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/chapter\/pathophysiology-of-intrinsic-asthma\/","title":{"raw":"6p12 Pathophysiology of Intrinsic Asthma","rendered":"6p12 Pathophysiology of Intrinsic Asthma"},"content":{"raw":"

What is the Underlying Pathophysiology of Intrinsic Asthma (Non-Allergic Asthma, Hyper-responsive Reaction)?<\/strong><\/h2>\r\n

Overview of Intrinsic Asthma (Adult-Onset):<\/strong><\/h1>\r\n
    \r\n \t
  • Etiology:<\/strong>\u00a0The precise mechanisms are less understood compared to extrinsic asthma.<\/li>\r\n \t
  • Potential Triggers & Theories:<\/strong>\r\n
      \r\n \t
    • T-Cell Activation:<\/strong>\u00a0Some researchers hypothesize that T cells may become inappropriately activated, causing inflammation without an allergic trigger.<\/li>\r\n \t
    • Cold Air & Respiratory Irritants:<\/strong>\u00a0Exercise or sudden cold exposure may irritate the respiratory tract, prompting immune responses.<\/li>\r\n \t
    • Autonomic Nervous System Imbalance:<\/strong>\u00a0The bronchial smooth muscles are innervated by the autonomic nervous system; an imbalance could cause excessive bronchoconstriction.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n

      Pathophysiology & Remodeling:<\/strong><\/h1>\r\n
        \r\n \t
      • Over time, both extrinsic and intrinsic asthma lead to airway remodeling:\r\n
          \r\n \t
        • Smooth Muscle Hypertrophy:<\/strong>\u00a0Thickening of the bronchial wall due to smooth muscle proliferation, leading to a narrowed lumen.<\/li>\r\n \t
        • Mucous Gland Hyperplasia:<\/strong>\u00a0Increased number and size of mucus glands, resulting in more mucus production with each attack.<\/li>\r\n \t
        • Mucosal Edema:<\/strong>\u00a0Swelling of the mucosa during inflammation.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t
        • These changes make airway obstruction more persistent and severe with recurrent attacks.<\/li>\r\n<\/ul>\r\n

          Symptoms and Attacks:<\/strong><\/h1>\r\n
            \r\n \t
          • Typical signs during an attack:<\/strong>\r\n
              \r\n \t
            • Cough (usually dry and nonproductive due to thick mucus plugs).<\/li>\r\n \t
            • Shortness of breath.<\/li>\r\n \t
            • Chest tightness.<\/li>\r\n \t
            • Wheezing from mucus plugs and bronchospasm.<\/li>\r\n \t
            • Use of accessory muscles (sternocleidomastoid, pectoralis minor) to breathe.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t
            • Physiological responses:<\/strong>\r\n
                \r\n \t
              • Hypoxia:<\/strong>\u00a0The brain triggers faster breathing and accelerates the heart rate to deliver more oxygen.<\/li>\r\n \t
              • Nighttime pooling:<\/strong>\u00a0Edema and mucus can accumulate when lying down, worsening breathing difficulties.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n

                Hemodynamic Changes:<\/strong><\/h1>\r\n
                  \r\n \t
                • Pulsus Paradoxus:<\/strong>\r\n
                    \r\n \t
                  • An abnormal decrease (>10 mm Hg) in blood pressure during inspiration compared to expiration.<\/li>\r\n \t
                  • Caused by exaggerated negative intrathoracic pressure during deep inspiration, affecting cardiac filling and blood pressure regulation.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n

                    Summary:<\/strong><\/h1>\r\nIntrinsic asthma<\/strong> involves airway hyper-responsiveness<\/strong> that may not be allergy-driven but could involve neural or immune dysregulation. Structural airway changes worsen with recurrent attacks, increasing severity and risk of chronic airflow limitation.","rendered":"

                    What is the Underlying Pathophysiology of Intrinsic Asthma (Non-Allergic Asthma, Hyper-responsive Reaction)?<\/strong><\/h2>\n

                    Overview of Intrinsic Asthma (Adult-Onset):<\/strong><\/h1>\n
                      \n
                    • Etiology:<\/strong>\u00a0The precise mechanisms are less understood compared to extrinsic asthma.<\/li>\n
                    • Potential Triggers & Theories:<\/strong>\n
                        \n
                      • T-Cell Activation:<\/strong>\u00a0Some researchers hypothesize that T cells may become inappropriately activated, causing inflammation without an allergic trigger.<\/li>\n
                      • Cold Air & Respiratory Irritants:<\/strong>\u00a0Exercise or sudden cold exposure may irritate the respiratory tract, prompting immune responses.<\/li>\n
                      • Autonomic Nervous System Imbalance:<\/strong>\u00a0The bronchial smooth muscles are innervated by the autonomic nervous system; an imbalance could cause excessive bronchoconstriction.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n

                        Pathophysiology & Remodeling:<\/strong><\/h1>\n
                          \n
                        • Over time, both extrinsic and intrinsic asthma lead to airway remodeling:\n
                            \n
                          • Smooth Muscle Hypertrophy:<\/strong>\u00a0Thickening of the bronchial wall due to smooth muscle proliferation, leading to a narrowed lumen.<\/li>\n
                          • Mucous Gland Hyperplasia:<\/strong>\u00a0Increased number and size of mucus glands, resulting in more mucus production with each attack.<\/li>\n
                          • Mucosal Edema:<\/strong>\u00a0Swelling of the mucosa during inflammation.<\/li>\n<\/ul>\n<\/li>\n
                          • These changes make airway obstruction more persistent and severe with recurrent attacks.<\/li>\n<\/ul>\n

                            Symptoms and Attacks:<\/strong><\/h1>\n
                              \n
                            • Typical signs during an attack:<\/strong>\n
                                \n
                              • Cough (usually dry and nonproductive due to thick mucus plugs).<\/li>\n
                              • Shortness of breath.<\/li>\n
                              • Chest tightness.<\/li>\n
                              • Wheezing from mucus plugs and bronchospasm.<\/li>\n
                              • Use of accessory muscles (sternocleidomastoid, pectoralis minor) to breathe.<\/li>\n<\/ul>\n<\/li>\n
                              • Physiological responses:<\/strong>\n
                                  \n
                                • Hypoxia:<\/strong>\u00a0The brain triggers faster breathing and accelerates the heart rate to deliver more oxygen.<\/li>\n
                                • Nighttime pooling:<\/strong>\u00a0Edema and mucus can accumulate when lying down, worsening breathing difficulties.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n

                                  Hemodynamic Changes:<\/strong><\/h1>\n
                                    \n
                                  • Pulsus Paradoxus:<\/strong>\n
                                      \n
                                    • An abnormal decrease (>10 mm Hg) in blood pressure during inspiration compared to expiration.<\/li>\n
                                    • Caused by exaggerated negative intrathoracic pressure during deep inspiration, affecting cardiac filling and blood pressure regulation.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n

                                      Summary:<\/strong><\/h1>\n

                                      Intrinsic asthma<\/strong> involves airway hyper-responsiveness<\/strong> that may not be allergy-driven but could involve neural or immune dysregulation. Structural airway changes worsen with recurrent attacks, increasing severity and risk of chronic airflow limitation.<\/p>\n","protected":false},"author":1370,"menu_order":13,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["zoe-soon"],"pb_section_license":"cc-by-nc-sa"},"chapter-type":[],"contributor":[60],"license":[57],"class_list":["post-4690","chapter","type-chapter","status-web-only","hentry","contributor-zoe-soon","license-cc-by-nc-sa"],"part":47,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters\/4690","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/users\/1370"}],"version-history":[{"count":4,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters\/4690\/revisions"}],"predecessor-version":[{"id":5305,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters\/4690\/revisions\/5305"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/parts\/47"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters\/4690\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/media?parent=4690"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapter-type?post=4690"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/contributor?post=4690"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/license?post=4690"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}