COPD

Risk factors:

• Tobacco smoking (90% of COPD)
• a₁-Antitrpsin deficiency

 

Diagnosis:

• ABG: chronic pCO₂ retention, ↓ pO₂, “60-60”
• CBC: ↑ hematocrit (bc of chronic hypoxia)
• Measure a₁-Antitrpsin levels if hx <50 yo

PFTs:

• ↓ FEV1 and ↓ FEV1\FVC
• ↑ TLC, RV, and FRC -> air trapping
• ↓ DLCO in case of emphysema

CXR:

• Emphysema: hyperinflation, flattened diaphragm, enlarged retrosternal space, diminished vascular markings (hyper-lucent lungs), ↑ AP diameter
• Useful in acute exacerbations -> rule out pneumonia and pneumothorax

ECG:

• Changes due to cor pulmonale: right atrial enlargement (peaked P wave = “P pulmonale”), right ventricular hypertrophy (right axis deviation)
• Other changes:

1. RBBB (due to RVH),
2. A fib, multifocal atrial tachycardia (MAT): rapid, irregular atrial tachycardia w\ at least 3 distinct P wave morphologies (associated w\ ↑ mortality COPD)

• Echo: right atrial\ventricular hypertrophy, pulmn HTN

 

Treatment:

• Improves mortality: smoking cessation, oxygen, vaccination
• Smoking cessation: slows the rate of FEV1 decline, but doesn’t completely reverse. Prolongs survival. Resp sx improve after 1 yr
• Combinations of B-agonists (albuterol) and anti-cholinergics (tiotrpium or ipratropium) -> most effective
• Inhaled corticosteroid (budesonide, fluticasone): may slows FEV1 decrease overtime. (systemic glucocorticoids are only used for acute exacerbations)
• Theophylline (controversial) -> may improve mucociliary clearance + central resp drive. Refractory COPD.
• Oxygen therapy: improves survival + QOL
• Vaccinations: against S. pneumonaie + influenza to COPD pts > 65 yo (or younger if ds is severe)
• Antibiotics: in acute exacerbations, change in sputum, worsening SOB
• Surgery: lung resection, lung transplantation

 

 

Treatment for acute exacerbation:  (↑SOB, sputum, cough)

• 1^st: B-agonist and\or anticholinergic (ipratropium)
• Systemic corticosteroids: for pts requiring hospitalizations -> IV methylprednisolone, taper w\ oral prednisone
• Antibiotics (broad spectrum), despite normal CXR
• Oxygen: nasal cannula\face mask -> keep at 90-93% (if >93% -> V\Q mismatch + loss of hypoxemic resp drive + Haldane effect)
• Noninvasive positive pressure ventilation (BIPAP or CPAP)
• If ↑ RR, PaCO₂, acidosis -> intubate and mechanical ventilate

 

Combined assessment of COPD: 

CAT score (assessment of symptom severity):

• < 10: less symptoms
• ≥ 10: more symptoms

FEV1 (GOLD classification):

• > 50%: low risk
• ≤ 50%: high risk

Exacerbations (hx of hospitalization):

• < 2: low risk
• ≥ 2: high risk

 

Prognosis:

BODE: 10-point scale

• BMI: <21 (+1)
• Obstruction (FEV₁): 50-64% (+1), 36-49% (+2), <35 (+3)
• Dyspnea (MRC scale): walking level (+1), 100 yards (+2), w\ ADL (+3)
• Exercise capacity (6 min walk): 250-349 m (+1), 150-248 m (+2), <149 (+3)

 

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Download the PDF version: here

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References: 

• Pocket medicine
• Step up to medicine
• Toronto notes
• The Johns Hopkins Internal Medicine Board Review