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93 Cards in this Set
- Front
- Back
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Obstructive Lung Disease |
lung disorders characterized by airway obstruction and impaired airflow |
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Obstructive Lung Disease includes... |
asthma COPD cystic fibrosis (also restrictive) |
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Caused by: 1. increased thickness of airway walls |
eg inflammation in chronic bronchitis |
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Caused by: 2. airway occlusion |
eg mucous accumulation in cystic fibrosis |
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Caused by: 3. bronchoconstriction |
eg during an asthma attack |
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Caused by: 4. loss of elastic fibers |
needed to keep airways open (eg emphysema) |
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Effects on Ventilation airways are pulled open during inspiration -> |
air flows past the obstruction |
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Effects on Ventilation obstructed airways collapse before expiration is complete-> |
problems getting air out |
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Effects on Ventilation air is trapped in the lungs -> |
more difficult to take in the next breath |
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Effects on Ventilation increased work of breathing -> |
accessory muscles are required |
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Effects on Ventilation air trapping causes lung hyperinflation |
increased lung volume barrel chest flattened diaphragm wide intercostal spaces |
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Lung Function Tests Forced vital capacity (FVC) |
the maximal volume of air forcefully exhaled |
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Lung Function Tests Forced vital capacity in 1 sec (FEV1) |
the volume of air forcefully exhaled in one second |
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Lung Function Tests normal FEV1/FVC is... |
80% |
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Lung Function Tests in obstructive lung disease, FVC is... FEV1 is... FEV1/FVC is... |
decreased decreased <70% |
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Lung Function Tests the rate of airflow is... |
slowed |
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Asthma |
chronic inflammatory disease of airways characterized by airflow obstruction and bronchial hyper responsiveness |
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Asthma affect... |
bronchioles and small bronchi |
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Asthma airways have an exaggerated tendency to.. |
narrow in response to various triggers |
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Asthma obstruction is reversible... |
spontaneously or with treatment |
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Asthma causes recurrent acute episodes of.. |
wheezing, chest tightness, cough and dyspnea |
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Asthma variability exists bw individuals |
eg frequency, severity, triggers |
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Asthma it cannot be cured but it can be controlled |
reduce frequency and severity of symptoms |
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Asthma poorly managed asthma results in airway remodeling |
permanent thickening of airway walls and obstruction |
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Asthma Etiology genetics |
predispose an individual to the development of asthma over 20 candidate genes have been identified (genes for IL-4, IgGE, beta adrenergic receptor, lipoxygenase) |
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Asthma Etiology proposed environmental factors |
exposure to allergens exposure to air pollution (urban home) exposure to cigarette smoke prenatal smoking and antibiotic use freq. childhood respiratory infections (syncytial) occupational exposure (paint, wood, dust, animals) |
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Asthma Triggers |
induce an acute attack |
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Asthma Classifications 1. allergic |
extrinsic asthma (initiated by exposure to an allergen) |
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Asthma Classifications 2. non-allergic |
intrinsic asthma (initiated by exposure to an airway irritant |
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Allergic Asthma accounts for most cases of... |
childhood onset asthma |
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Allergic Asthma individuals have a genetic predisposition to... |
develop IgE in response to allergens (=atopy) |
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Allergic Asthma individuals have elevated serum... |
IgE levels |
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Allergic Asthma individuals often have other... |
allergic disorders hayfever, eczema |
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Sensitization |
occurs with the initial exposure to an allergen |
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Sensitization an abnormal immune response leads to the production of large amounts of... |
allergen specific-IgE |
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Sensitization IgE that isnt exposed to the allergen binds to airway... |
mast cells =airway sensitization |
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Sensitization the abnormal immune response involves an imbalance between... |
TH1 and TH2 production (favoring TH2 cells) |
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Sensitization during subsequent allergen exposure-> the allergen cross-links IGE molecules bound to mast cells of sensitized airways... |
mast cell activation causes an acute asthma attack |
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Non-Allergic Asthma triggers and exposure include... |
viral respiratory infections, bronchial irritants |
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Non-Allergic Asthma counts for... |
30% of asthmatics |
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Non-Allergic Asthma usually develop asthma as an... |
adult |
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Non-Allergic Asthma no identifiable... |
allergens or genetic link |
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Non-Allergic Asthma individuals have unusually sensitive or... |
hyper-responsive airways (mechanism not understood) |
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Non-Allergic Asthma there is a chronic underlying airway inflammation (even when asymptomatic) or an imbalance in autonomic innervation that makes these airways... |
hyper-responsive |
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Non-Allergic Asthma Respiratory infections |
most common asthma trigger |
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Non-Allergic Asthma Respiratory infections viral infections cause damage to the epithelium causing... |
airway inflammation |
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Non-Allergic Asthma Respiratory infections increases airway sensitivity to other... |
triggers |
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Non-Allergic Asthma Exercise loss of heat and water from airways cause... |
irritation and inflammation worse in cold, dry weather |
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Non-Allergic Asthma Exercise attacks occur when exercise stops and airways are... |
less dilated within 3 min resolves within 60 min |
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Non-Allergic Asthma Aspirin, NSAIDS attacks occur... |
with min to hours (up to 12) of ingestion |
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Non-Allergic Asthma Aspirin, NSAIDS blocks... |
COX enzyme synthesis and PG synthesis |
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Non-Allergic Asthma Aspirin, NSAIDS causes a relative increase in LT synthesis |
bronchoconstricition |
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Non-Allergic Asthma inhaled irritants cause airway inflammation and stimulate... |
irritant receptors causing bronchoconstriction |
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Acute Asthma Attack allergic asthma is divided into 2 phases |
acute asthmatic response
late asthmatic response |
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Acute Asthma Attack The early response allergens activate mast cells (and TH2 cells) on the... |
mucosal surface and within airway walls |
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Mast Cell Activation results in the release of preformed inflammatory mediators such as... |
histamine and chemotactic factors |
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Mast Cell Activation results in the synthesis of... |
prostaglandins and leukotrienes (slower but more prolonged response) |
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Mast Cell Activation TH2 cells release... |
cytokines that contribute to inflammation |
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Early Airway Changes muscle |
contracts and constricts airways
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Early Airway Changes airway |
swelling (edema) |
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Early Airway Changes mucus |
production |
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Acute Relief symptoms related to an obstruction occur within... |
minutes of allergen exposure and last up to an hour |
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Acute Relief an inhaled bronchodilator... |
short acting beta2 agonist, is taken immediately |
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Acute Relief an inhaled bronchodilator relaxes... |
bronchial smooth muscle and increases airflow within 5 min. |
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Late Response symptoms recur... |
4-12h following the initial attack (may last for days) |
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Events of the Late Response 1. prolonged action of... |
prostaglandins and leukotrienes |
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Events of the Late Response 2. the recruitment of eosinophils by... |
chemotactic factors released by TH2 cells and mast cells |
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Events of the Late Response 3. parasympathetic |
reflexes |
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Airway remodeling |
occurs with frequent, severe cute asthma attacks (poorly managed asthma) |
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Airway remodeling |
causes irreversible changes |
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Airway remodeling 1. epithelial cell damage stimulates... |
collagen deposition and fibrosis |
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Airway remodeling 2. airway smooth muscle layer... |
thickens |
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Airway remodeling 3. mucus glands hypertrophy and goblet cells replace lost... |
epithelial cells |
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Airway remodeling = |
permanent obstruction
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Clinical Manifestations Mild attack |
wheezing (narrowed airways) cough (irritant receptor stimulation with mucus and inflammation) chest tightness (air trapping) dyspnea slight tachypnea and tachycardia |
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Clinical Manifestations Severe attack |
wheezing (narrowed airways) severe dyspnea (unable to complete sentences) labored breathing (use of accessory muscles) chest hyperexpansion tachypnea (>30 RR) tachycardia (>120 bpm) anxiety |
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Role of Eosinophils release proteins (major basic proteins) |
normally toxic to parasites cause airway epithelial damage and inflammation |
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Role of Eosinophils creola bodies |
shed epithelial cells are found in the sputum of symptomatic asthmatics dx asthma vs chronic bronchitis |
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Parasympathetic Reflexes epithelial damage exposes... |
subepithelial sensory nerve endings |
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Parasympathetic Reflexes activates parasympathetic (vagal) reflexes causing... |
further bronchoconstriction and mucus secretion |
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Effects on lung function (reversible) partial airflow obstruction causes... |
air trapping |
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Effects on lung function (reversible) total obstruction of airways causes... |
obstructive atelectasis (severe asthma attack) |
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Effects on lung function (reversible) increased work of breathing... |
uses accessory muscles |
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Effects on lung function (reversible) impaired work of breathing leads to V/Q mismatch... |
hypoxemia |
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Effects on lung function (reversible) compensatory hyperventilation initially-> |
rapid respiration and respiratory alkalosis |
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Effects on lung function (reversible) widespread obstruction and decreased ventilation (due to hyperinflation and decreased compliance) -> |
shallow breaths, hypercapnia and respiratory acidosis |
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Diagnosis FEV1 measured before and after use of an inhaled short acting beta2 agonist |
FEV1 % will increase, suggesting reversibility |
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Diagnosis blood cell differential |
eosinophils |
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Diagnosis chest x-rays |
diaphgram flatterning |
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Diagnosis sputum sample |
creola bodies |
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Treatment Prevention |
removal of triggers (#1 measure) |
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Treatment Quick Relief |
rescue inhaler minimize use |
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Treatment chronic management |
minimize chronic symptoms depend on classification (clinical severity) inhaled corticosteroids long acting beta2 agonist leukotriene receptor antagonist mast cell inhibitors oral corticosteroids immune therapy |
