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What is the pathopysiology of COPD?
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COPD is characterized by increased airway secretions and mucosal edema, leading to airflow obstruction.
There is also bronchoconstriction and bronchospasm secondary to decreased lung elasticity.
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Is all COPD due to cigarette smoking?
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No, but most (80-90%) is. Other causes of COPD are chronic respiratory infections, environmental exposure, second hand smoke and diet.
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The two major types of COPD are bronchitis and emphysema. What is the primary problem in each of these?
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Emphysema is characterized by permanent enlargement and destruction of air spaces distal to terminal bronchioles. Bronchitis is characterized by excess mucus production and chronic cough. Cough must be >3 mos. x 2 yrs
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Are diagnoses of bronchitis and emphysema mutually exclusive?
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No. Most people have both, but one form predominates over the other in terms of clinical features.
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What clinical features would you expect to see in a patient with an acute exacerbation of COPD?
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Dyspnea, chest tightness, wheezing, change in character of cough
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What gas abnormality would you be worried about in a COPD patient with confusion, tremor and who is stuporous?
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Hypercapnia can cause these symptoms, and tells you the patient is unable to exchange/blow off their excess CO2.
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Why is pulse oximetry of no value in predicting clinical outcomes in AECOPD? What test is more valuable than pulse oximetry.
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Pulse oximetry is of no value because it does not tell you about hypercapnia or acid-base disturbances. Arterial blood gases tell you both of these, and hypercapnia and respiratory acidosis are both indicative of respiratory fatigue/acute resp failure
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What ECG changes might you find in moderate to severe COPD?
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Signs of RV strain - ST depression and T wave inversion in leads V1-V3, possibly in II, III and aVF.
You may also find abnormal P waves in moderate-severe COPD.
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Describe the treatments you would use for a moderate COPD exacerbation.
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1)Oxygen to keep sats 90-92% (prevent suppression of hypoxic drive and hypercarbia) 2)B2-agonists (eg. albuterol 2.5 mg neb or by MDI) 3)Anticholinergics (eg. Atrovent 500 mcg neb or by MDI) 4) Systemic corticosteroids (40-60 mg prednisone for 3-10 days)
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What further treatments would you consider in a severe COPD exacerbation?
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5)MgSO4 1-2g iv 6)Non-invasive positive pressure ventilation (eg. cPAP or BiPAP) 7)Mechanical ventilation as a last resort for patients with hypoxia/hypercarbia, worsening acidosis and altered LOC
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What common acute complication of COPD is often seen on CXR?
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Pneumothorax
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Are antibiotics needed in the treatment of AECOPD?
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This is controversial. However, if there are 2 of increased sputum, purulent sputum or increased dyspnea, it is reasonable to give a course of antibiotics. Amoxil 500 mg po tid x 10 days, doxycycline 150 mg po daily x 10 days or TMP/SMX 160 mg po bid x 10
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