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OBSTRUCTIVE DISEASES

OBSTRUCTIVE DISEASES. Causes of airway narrowing Loss of tethering Airway smooth muscle constriction Airway plugging (mucous, foreign body) Airway edema. Normal. Emphysema. Causes of airway narrowing Loss of tethering Airway smooth muscle constriction

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OBSTRUCTIVE DISEASES

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  1. OBSTRUCTIVE DISEASES

  2. Causes of airway narrowing • Loss of tethering • Airway smooth muscle constriction • Airway plugging (mucous, foreign body) • Airway edema

  3. Normal Emphysema

  4. Causes of airway narrowing • Loss of tethering • Airway smooth muscle constriction • Airway plugging (mucous, foreign body) • Airway edema

  5. Epithelial Cell Air Smooth Muscle Cell

  6. Causes of airway narrowing • Loss of tethering • Airway smooth muscle constriction • Airway plugging (mucous, foreign body) • Airway edema

  7. Mucus filling the airway lumen in asthma

  8. Causes of airway narrowing • Loss of tethering • Airway smooth muscle constriction • Airway plugging (mucous, foreign body) • Airway edema

  9. Normal Airway Edema

  10. Measuring airway obstruction

  11. AIRWAY OBSTRUCTION: FEV1/FVC < 80%

  12. Normal values for lung volume depend on: • Age • Sex • Height • Race • Weight (for some subdivisions of lung volume)

  13. DEFINITION OF ASTHMA 1. Reversible Airway Narrowing 2. Increased Airway Responsiveness 3. Airway Inflammation (History of Allergy)

  14. Epithelial Cell Air Smooth Muscle Cell

  15. MUCOUS HYPERSECRETION IN ASTHMA Jeffrey et al, Am. J. Respir. Crit. Care Med. 2001 164: 28S-38S

  16. DEFINITION OF ASTHMA 1. Reversible Airway Narrowing 2. Increased Airway Responsiveness 3. Airway Inflammation (History of Allergy)

  17. AIRWAY HYPERRESPONSIVENESS

  18. DEFINITION OF ASTHMA 1. Reversible Airway Narrowing 2. Increased Airway Responsiveness 3. Airway Inflammation (History of Allergy)

  19. Th2-lymphocytes • promotes IgE formation (IL-4, IL-13) • promotes eosinophil migration (IL-5) Eosinophil • promotes contraction of smooth • muscle • promotes recruitment of more • eosinophils

  20. Normal Major Basic Protein Staining (eosinophils) Asthma • van den Toorn et al, Am. J. Respir. Crit. Care Med. 2001 164: 2107-2113

  21. Symptoms of Asthma: • cough • shortness of breath • chest tightness • wheezing

  22. HISTOLOGICAL FEATURES OF ASTHMA • Subepithelial fibrosis • Mucous cell hyperplasia • Smooth muscle hypertrophy • Increased vascularity

  23. BASEMENT MEMBRANE THICKENING IN ASTHMA • Jeffrey et al, Am. J. Respir. Crit. Care Med. 2001 164: 28S-38S

  24. INCREASED MUCOUS PRODUCING CELLS (blue purple stain) Normal Asthma • Ordonez et al, Am. J. Respir. Crit. Care Med. 2001 163: 517-523

  25. MUCOUS HYPERSECRETION IN ASTHMA Jeffrey et al, Am. J. Respir. Crit. Care Med. 2001 164: 28S-38S

  26. AIRWAY SMOOTH MUSCLE HYPERTROPHY IN ASTHMA Jeffrey et al, Am. J. Respir. Crit. Care Med. 2001 164: 28S-38S

  27. INCREASED AIRWAY VASCULARITY IN ASTHMA Jeffrey et al, Am. J. Respir. Crit. Care Med. 2001 164: 28S-38S

  28. Pulmonary Function • Total lung capacity is usually normal, but the FRC is elevated and RV is increased • Decreased FEV1/FVC ratio • Lung stiffness is usually normal or low • Airway obstruction is due to smooth muscle constriction and mucus hypersecretion

  29. AIRWAY OBSTRUCTION: FEV1/FVC < 80%

  30. asthma

  31. Blood gases • PaO2 • - low because of mismatch of ventilation • and perfusion • PaCO2 • often low (hyperventilation due to anxiety) • if PaCO2 increases it’s usually a sign that • respiratory failure is approaching • (patient needs to be ventilated)

  32. Epidemiology of Asthma • currently affects 5-10% of US population • incidence and severity are increasing • mortality has plateaued • Still relatively rare • highest in industrialized countries • Higher in urban than rural areas

  33. Asthma PrevalenceUnited States, 1980-2004 Lifetime Current 12-Month Attack Source: National Health Interview Survey; National Center for Health Statistics

  34. IgE Chemicals released: • histamine • leukotrienes • proteases • cytokines (IL-4, IL-5) Allergen Mast cell

  35. Mast Cell Smooth Muscle Cell (releases chemicals) (contracts)

  36. Early Response Late Response 100 90 FEV1.0 (% baseline) 80 70 60 1 2 3 4 5 6 7 8 Allergen Time (hours)

  37. Mast Cell White blood cells

  38. Mast Cell Smooth Muscle Cell

  39. Early Response Late Response 100 90 FEV1.0 (% baseline) 80 70 60 1 2 3 4 5 6 7 8 Allergen Time (hours)

  40. Allergen avoidance

  41. Allergy skin testing team.zobel.dlsu.edu.ph/sites/students/G6/List...

  42. MOST IMPORTANT ALLERGENS IN THE US • Cat • House dust • Cockroach • Mold

  43. Cat washing itself aerosolizes allergen www.tiedye.com/cats.htm

  44. Cat being washed – helps reduce allergen exposure (recommended 2X/week) www.dkimages.com/.../Cat-Care/Cat-Care-054.html

  45. House Dust Mite - Dermatophagoides sp. 100 mm The average pillow is home to 10,000 of these!

  46. Avoiding exposure to dust mite allergens • Encase pillows and mattresses • Use HOT (>130oC) water to wash bedding and clothes • Reduce carpeting (in particular wall to wall carpeting, which cannot be adequately cleaned) • Reduce humidity (mites are dependent on water in the air for their water supply) • Avoid fabric coverings on furniture and windows Platts-Mills et al, J Allergy Clin Immunol. 2000 Nov;106(5):787-804

  47. The American cockroach • A particular problem in low income housing • Insects move from one apartment to another

  48. Mold

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