Pulmonary disorder - Asthma Flashcards
what is asthma?
chronic inflammatory disease
what is asthma characterized by?
bronchial hyperreactivity, airway constriction, variable airway obstruction that is reversible
how many genes have been identified that play a role in asthma?
over 100 genes
what are the symptoms of asthma?
wheeze, shortness of breath, chest tightness and cough
what are the two responses to airway epithelial exposure?
early and late asthmatic response
what does antigen exposure to the bronchial mucosa activate in the early asthmatic response? what do these cells then do? what occurs as a result? what kind of antibodies are produced?
dendritic cells, activate helper t cells, which activate B cells and make them produce IgE antibodies
what do IgE antibodies do?
they bind to the surface of mast cells which cause mast cell degranulation which releases inflammatory mediators
what are the different inflammatory mediators released during mast cell degranulation?
bradykinins, histamine, prostalglandin, leukotrienes, interlukins,
what do the inflammatory mediators released from the early asthmatic response do?
cause vasodilation, vascular permeability, edema, bronchospasm, mucous secretion, airway constriction and obstruction to airflow
when does the late asthmatic response occur?
4 to 8 hours after the early response
what is there a release of during the late asthmatic response?
there is a release of inflammatory mediators
what does synthesis of leukotrienes during the late response cause?
causes prolonged bronchospasm
what does damage to epithelial cells during the late asthmatic response lead to?
accumulation of mucus and cellular debris in the airways
what do eosinophils in the late asthmatic response do?
they cause direct tissue injury, proliferation of fibroblasts and airway scarring
what is airway remodeling?
permanent airway damage due to chronic inflammation
what does airflow obstruction increase?
increases resistance to airflow and expiratory flow rates
what does impaired expiration cause?
air trapping, hyperinflation and increased work of breathing
what does uneven distribution of air in the lungs lead to?
V/Q mismatch and hypoxemia
what is hyperventilation triggered by?
increased lung volume and obstruction
what does prolonged obstruction of expiratory airflow do to the thorax?
it causes it to be hyperextended
what does a hyperextended thorax lead to?
decreased in TV, hypoventilation and acidosis
what is a pulse paradoxus?
a decrease in systolic blood pressure during inspiration
what are the symptoms of asthma during an attack?
wheezing, nonproductive cough, chest constriction, tachypnea, tachycardia, dyspnea, prolonged expiration and use of accessory muscles to breath
what else may be noted during an attack?
a pulse paradoxus
what is status asthmaticus?
the condition when bronchospasms cannot be reversed by usual treatment measures
