COPD

Question 1

Chronic Bronchitis Basics

Answer 1

• CLINICAL dx - productive cough for 3+ mo for 2 successive yrs
• Histo - airway inflammation, airway edema, mucus gland hypertrophy and excessive bronchial secretions
• Source of Resistance - narrowing of lumen from inflammation. edema and secretions

Question 2

Emphysema Basics

Answer 2

• HISTO/ANATOMIC dx - destruction of alveolar walls –> permanent airspace enlargement AND destruction of pulmonary capillary bed (distal to terminal bronchioles)
• Source of Resistance - loss of tethering effect of pulm parenchyma on the small airways –> lose patency during expiration AND pleural p becomes more pos –> airways collapse

Question 3

How are lung volumes affected in emphysema?

Answer 3

-Dec elastic recoil of lungs so get to FRC at higher pressure (inc FRC)

• Dec elastic recoil also means lungs can stretch to great max vol in inspiration (inc TLC)
• *Inc in TLC is less than inc FRC (so less inspiratory capacity)

-Also inc RV

Question 4

Exercise Induced Hypoxemia in Emphysema

Answer 4

• capillary destruction –> inc blood velocity even at rest (same CO must go thru smaller + caps)
• SO w/ exercise CO inc even more –> insufficient time for equilibrations at cap interface –> dec PaO2
• Emphysema is only obstructive disease w/ dec diffusion capacity due to cap destruction

Question 5

COPD Risk Factors

Answer 5

• Exposure to toxic fumes and gases - SMOKING, air pollution (dec max lung funct normally attained in young adulthood; quicker plateau then more rapid dec in function w/ age)
• Mucus hypersecretion and inc # acute exacerbations
• Strong correlation b/n childhood resp infections and COPD

Question 6

COPD Pathophysiology

Answer 6

• Smoking –> recruit neutrophils –> inflammation
  
  • Both smoke and neutrophils inc the oxidant burden
• How inflammation is sustained in UNKNOWN
• Hypo - imbalance b/n proteinases (destroy lung tissue) and anti-proteinases –> ECM destruction and cells not attached to matrix are more susceptible to death + impairment of repair –> enlarged air space/depleted parenchymal elastic fibers/abnormal collagen arrangement
• Ex) dec in alpha-1 antitrypsin which normally inhibits neutrophil elastase (now more elastic destruction by neutrophils)

Question 7

Signs/Symptoms

Answer 7

• Cough (mucoid but maybe purulent in acute infections), dyspnea (why ppl present)
• PE - prolonged expiratory time (>4 sec), maybe some rhonchi or wheezing (level of wheezing does not relate
  to severity)
• Later - barrel chest, pursed lips during breathing, emaciation
• “Tripodding” - sit forward and support upper body w/ extended arms

Question 8

COPD Imaging

Answer 8

• X-ray used to r/o other causes NOT SPECIFIC; but may see inc lung markings and inc thickness of bronchial walls
  
  • May see hyperinflation - flattened or concave diaphragm
• CT - better for pulm parenchyma; can quantify severity and anatomic extent; can see bullae
• Not diagnostic; must do functional tests

Question 9

COPD Complications (3)

Answer 9

• Pneumothorax - if sudden worsening of dysnpea; can be life-threatening
• Cor Pulmonale - results from alveolar hypoxia –> vasoconstriction
• Systemic - CVD, skeletal muscle weakness, bone disease, weight loss (all due to metabolic alterations and maybe inc circulating inflammatory cytokines - TNF-alpha and IL-6)

Question 10

Smoking Cessation Strategies (4)

Answer 10

• Nicotine replacement
• Buproprion - inhibits NE, serotonin and dopamine reuptake; reduces urge by more neuroTs available and dec reward
• Varinicline Tartrate (Chantix) - partial nicotine agonist; can also antagonize nicotine to blunt reward when ppl do smoke
• E-cigs release propylene glycol vapor w/o CO, carcinogens or hydrocarbons; 10% as much nicotine

Question 11

Meds and Therapies for COPD

Answer 11

-Smoking cessation

• Meds -
  - Bronchodilators improve quality of life, dec exacerbation freq, maintain function
  - Steroids do not improve function but dec exacerbation freq and improve quality
  - Azithromycin / PDE4 inhibitor (roflumilast) - dec exacerbation freq in more severe COPD patients w/ very
• Oxygen
• Pulmonary Rehab (education, exercise, psychosocial/behavioral support groups)
• Surgery - lung vol reduction in upper lobe dominant emphysema (allows healthy lung tissue to take up that space –> inc elastic recoil and dec hyperinflation to return diaphragm to normal shape) OR transplant (inc quality of life but not survival benefit)