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8/2/2019 Pa Tho Physiology of COPD
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Pathophysiology of Chronic
Obstructive Pulmonary Disease
8/2/2019 Pa Tho Physiology of COPD
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COPD types
Chronic Bronchitis
Emphysema
Bronchiectasis
destruction and widening oflarge airways
Asthma
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General COPD Progression
Most cases are a result of exposure to noxious
stimuli, most often cigarette smoke.
Pathogenic mechanisms are unclear
Increased numbers of PMN leukocytes and
macrophages release elastases in a manner
that cannot be counteracted effectively by
anti-proteases, resulting in lung destruction.
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Chronic Bronchitis
Defined as presence of a chronic productivecough for 3 months during each of 2consecutive years
Mucous gland hyperplasia is the histologichallmark
Damage to endothelium impairs mucociliary
response Contrast to emphysema, has relatively
undamaged pulmonary capillary bed.
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Histologic hallmark
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Emphysema
Defined as abnormal, permanent enlargement of the airspaces distal to the terminal bronchioles, accompanied bydestruction of their walls and without obvious fibrosis.
Airway limitation is due to loss in elastic recoil and increase
in airway resistance. Permanent enlargement of airspaces distal to the terminal
bronchioles.
Gradual destruction of alveolar septae and pulmonarycapillary bed leads to decreased ability to oxygenate blood
2 mechanisms of airflow limitation Loss of alveolar walls results in decrease in elastic recoil
Loss of alveolar supporting structure leads to airway narrowing.
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Chronic Bronchitis Emphysema
inflammation, or irritation, in the
bronchioles of the lungs.
permanent enlargement of the airways in
your lungs, accompanied by alveoli
destruction
Body responds by decreasing ventilation
and increasing cardiac output
Body responds by hyperventilation and
decreasing cardiac output
V/Q mismatch leading to hypoxemia(blue)
and polycythemia
V/Q mismatch leads to hypoxia(relatively
pink)
Hypercapnia and respiratory acidosis Lack of radial traction on bronchioles
leads to marked tendency to collapse
during expiration due to expiratory
positive pleural pressures
Pulmonary artery vasoconstriction and
Cor Pulmonale(alteration in the structure
and function of the right ventricle causedby a primary disorder of the respiratory
system)
Patient breathes through mouth with
gradual release of pressure so there is
more intra bronchial pressure to preventairway collapse(Purse lip breathing)
Right heart fibrillation leading to
edema(bloaters)
In other words, patient puffs breathing.
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References
http://emedicine.medscape.com/article/2976
64-overview#showall
http://www.prep4usmle.com/forum/thread/7
4374/
http://emedicine.medscape.com/article/297664-overviewhttp://emedicine.medscape.com/article/297664-overviewhttp://www.prep4usmle.com/forum/thread/74374/http://www.prep4usmle.com/forum/thread/74374/http://www.prep4usmle.com/forum/thread/74374/http://www.prep4usmle.com/forum/thread/74374/http://www.prep4usmle.com/forum/thread/74374/http://www.prep4usmle.com/forum/thread/74374/http://emedicine.medscape.com/article/297664-overviewhttp://emedicine.medscape.com/article/297664-overviewhttp://emedicine.medscape.com/article/297664-overviewhttp://emedicine.medscape.com/article/297664-overviewRecommended