COPD

Question 1

COPD Definition

Answer 1

Characteristized by chronic airflow limitation which is not fully reversible

Includes:

• Emphysema: destruction and enlargement of alveoli
• Chronic bronchitis: chronic cough and phlegm production
• Small airway disease: narrowing of small bronchioles

Question 2

Risk Factors

Answer 2

Cigarette smoking

Asthma (increased airway responsiveness)

Occupational exposures, air pollution (indoor and outdoor), and second hand smoke (less important than smoking)

α₁ Antitrypsin Deficiency

GERD

Other associations: age, FHx of COPD, and low SES

Question 3

Molecular Pathogenesis of COPD

Answer 3

Inflammation

• Smoking activates epithelial cells and alveolar macrophages, and destroys cilia
• Neutrophils and macrophages are recruited and accumulate in alveoli and respiratory bronchioles, leading to the accumulation of pus.
• Loss of cilia leads to decreased clearing of the inflammatory cells.
• Neutrophils and macrophages release free radicals, inhibiting antiproteases, and leading to the destruction of tissue (**ECM Degradation) **edema, and mucus hypersecretion.

Cell Death–Both cells and matrix disappear leading to airspace enlargement

Ineffective Repair– Limited ability to repair alveolar damage

Question 4

Pathology of COPD (Large airways, small airways, parenchyma)

Answer 4

Large Airways

• Squamous metaplasia in bronchi (dec’d ciliary clearance of mucus)
• Hypertrophy of bronchial smooth muscle, therefore bronchial hyperreactivity and air flow obstruction

Small Airways

• Clara cells (surfactant) replaced by goblet cells (mucus)
• Airway narrowing secondary to fibrosis, edema, cellular inflammation, mucus
• Loss of patency secondary to loss of parenchyma

Parenchyma

• Destruction fo respiratory bronchioles, alveolar ducts, and alveoli (gas exchange surfaces)
• Loss of elastic recoil (affects the bellows function0

Question 5

Bellows function

Answer 5

Impaired movement of air due to decreased elastic recoil and support for airways (inc’d resistance)

Obstructive pattern on spirometry

Question 6

Changes in Lung Volumes in COPD and its Effects

Answer 6

Air trapping because decreased elastic recoil leads to incomplete expiration. This increases residual volume.

Therefore, hyperinflation occurs, increasing the work of breathing as diaphragm flattens

Because of the air trapping, VQ mismatches occur.

Pulmonary HTN occur, which may lead to cor pulmonale and RV failure

Question 7

Type A vs. Type B

Answer 7

Type A:

• Dry emphysema: cough, dyspnea, barrel chest, CXR with hyperinflation.
• No fibrosis and decreased pulmonary vasculature
• Prognosis good

Type B:

• Wet emphysema: severe cough with copious sputum production; rales; wheezing; cyanosis.
• Moderate hyperinflation on CXR and dyspnea later
• Fibrosis in lower lobes, increase in central pulmonary vascularity

Question 8

COPD Recap (Reference)

Answer 8

• airflow limitation (loss of elastic recoil and supporting tissue)
• airflow obstruction (mucus hypersecretion, mucus plugging, airway edema, bronchospasm)
• increased work of breathing (increased airway resistance, hyperinflation) may lead to alveolar hypoventilation, hypocapnia, and hypoxia
• also, hypoxia from V/Q mismatch
• hypoxemia → increase pulmonary vascular tone → pulmonary hypertension→ cor pulmonale

Question 9

Diagnosis

Answer 9

**Dyspnea **

• Most significant presenting symptom. Described variably
• Modified Medical Research Council Questionnaire for Assessing the Severity of Breathlessness

Cough

• Chronic cough that is progressive (intermittent to throughout the day)

**Sputum Production **

• regular sputum production in three or more months in 2 consecutive years (chronic bronchitis definition)
• Often small amounts of tenacious sputum. Purulent sputum suggests inflammation
• Large volumes of sputum may suggest bronchiectasis

Wheezing and Chest Tightness

• Non-specific, more commonly found in severe COPD
• Does not differentiate between COPD and asthma, or rule in or r/o either

Question 10

Physical Exam

Answer 10

No specific findings, only suggestive

Hyperinflation of chest/barrel chest

Use of accessory muscles, paradoxical lower rib movement, reduced expansion

Pursed lip breathing, prolonged expiration

Distant breath sounds, hyperresonant chest

Signs of cor pulmonale: peripheral edema, elevated JVP, hepatomegaly

Signs of hypoxemia

Cachexia

Question 11

Ancillary Examinations (tests)

Answer 11

Spirometry to measure airflow obstruction

CXR to r/o other pathologies

Hemoglobin (anemia or polycythemia)

CT if sxs > PFTs

EKG, echo

Oximetry

Question 12

Differential Diagnosis

Answer 12

Asthma

Bronchiectasis

Obliterative bronchitis

CHF

Upper airway lesions, including LCA

Question 13

Treatment Goals of COPD

Answer 13

Control sxs

Improve exercise tolerance

Decrease frequency and severity of exacerbations

Question 14

Management of Stable COPD

Answer 14

Spirometry should be used to screen and diagnose airflow obstruction.

Avoid Risk Factors

Influenza vaccine annually

Pneumococcal polysaccharide vaccine (S. pneumo)

Treat complications

Pulmonary Rehab: improves survival, quality of life (inc’d exercise tolerance, reduces hospitalizations, psychosocial benefit, benefits extend beyond period of training)

Question 15

Changes in quality of life

Answer 15

Depression due to changes in exercise tolerance, difficulty with “just trying to breathe,” etc.

Social isolation as activity becomes more difficult, oxygen apparatus limits movements, etc.

Question 16

Oxygen therapy in COPD

Answer 16

Improves survival in pts with severe hypoxemia when used >15hrs/day

Question 17

Acute Exacerbations of COPD

Answer 17

Increased dyspnea (at rest), heart rate (>110), cough, or sputum production

Increased ventilatory rate (>25)

Hypoxemia (cyanosis)

Fever

Change in sputum color or character

New use fo accessory muscles

Development or increase in wheezing

Peripheral edema

Change in mental status

Fatigue

Decrease in peak flow or FEV1

Chest tightness

BOLD = SEVERE EXACERBATION

Question 18

Tests in Acute Exacerbation of COPD

Answer 18

Hx: Focus on previous exacerbations, triggers, changes in meds

PE: identifying signs of exacerbation (vital signs, oxygen saturation, etc.)

CXR if pneumonia is suspected, CBC (infection)

ABG if O2 sat <88%. If pH <7.32, admit because risk of respiratory failure

CT, BNP, echo, EKG if HF suspected and dx unclear

Question 19

Spontaneous ___________ can occur in moderate to severe COPD

Answer 19

pneumothorax

Up to 50% will experience a second if pleurodesis is not performed after first one