Section 2: Asthma and COPD 2

Question 3

Diagnosis: Decreased TLC, Decreased RV, Decreased VC, Normal FEV₁, Normal FEV₁/FVC ratio, Normal DL_CO

Answer 3

Extra-parenchymal (extra-thoracic) restriction

• Kyphosis
• Obesity

Question 4

Diagnosis: Increased TLC, Increased RV, Decreased FEV₁, Decreased FVC, Decreased FEV₁/FVC ratio, Decreased DL_CO

Answer 4

COPD

Question 5

Diagnosis: Normal or Increased TLC, Normal or Increased RV, Decreased FEV1, Decreased FVC, Normal or Decreased FEV1/FVC ratio, Normal or Increased DLCO

Answer 5

Asthma

Question 6

Diagnosis: Decreased TLC, Decreased RV, Decreased FEV₁, Decreased FVC, Normal or Increased FEV₁/FVC ratio, Decreased DL_CO

Answer 6

Fibrotic (or Interstitial Lung) Disease

Question 7

List the minimum that should be done for all patients with shortness of breath (SOB)

Answer 7

Oxygen

Continuous oximeter

Chest X-ray

Arterial blood gas (ABG)

Question 8

Causes of low DL_CO

Answer 8

Emphesema

Pneumonectomy

Interstitial lung disease

pulmonary embolism

Pulmonary HTN

Question 9

Arterial blood gases measurements

Answer 9

pH: 7.35 to 7.45

PCO₂: 33-45mmHg

PO₂: 75-105mmHg

Question 10

What is A-a gradient?

Answer 10

A-a gradient is alveolar-arterial gradient (PAO₂-PaO₂ gradient). It is a useful calculation for the assessment of oxygenation. A-a gradient increases with age and is only valid in room air. It is calculated as follows:

PA0₂-Pa0₂ gradient = 150 - 1.25 X PaCO₂ - PaO₂

i.e.,

A-a gradient = [150 - (1.25 X PaCO₂) - PaO₂]

This gradient is between 5 and 15 mmHg in normal young adults. It increases with all causes of hypoxemia except hypoventilation and high altitude

Question 11

List the typical physical findings in COPD

Answer 11

Barrel-shaped chest

Clubbing of fingers

Increased anterior-posterior diameter of the chest

Loud P2 heart sound (sign of pulmonary hypertension)

Edema as a sign of decreased right ventricular output (the blood is backing up due to the pulmonary hypertension)

Question 12

Laboratory findings in COPD

Answer 12

EKG: Right axis deviation, right ventricular hypertrophy, right atrial hypertrophy

Chest x-ray: Flattening of the diaphragm (due to hyperinflation of the lungs), elongated heart, and substernal air trapping

CBC: Increased hematocrit is a sign of chronic hypoxia. Reactive erythrocytosis from chronic hypoxia is often microcytic. An erythropoietin level is not necessary.

Chemistry: Increased serum bicarbonate is metabolic compensation for respiratory acidosis.

ABG: Should be done even in office-based cases to assess CO2 retention and the need for chronic home oxygen based on pO2 (you expect the pCO2 to rise and the pO2 to fall).

Pulmonary function testing (PFT): You should expect to find the following:

– Decrease in FEV1

– Decrease in FVC from loss of elastic recoil of the lung

– Decrease in the FEV1/ FVC ratio

– Increase in total lung capacity from air trapping

– Increase in residual volume

– Decrease in diffusion capacity lung carbon monoxide (DLCO) caused by destruction of lung interstitium

Question 13

Chronic medical therapy for COPD

Answer 13

Tiotropium or ipratropium inhaler

Albuterol inhaler

Pneumococcal vaccine: Heptavalent vaccine,

Pneumovax Influenza vaccine: Yearly

Smoking cessation

Long-term home oxygen if the pO2 < 55 or the oxygen saturation is < 88 percent

Question 14

Name two interventions that lower mortality in COPD

Answer 14

Smoking cessation

Home oxygen therapy (continuous)

Question 15

Spot Diagnosis: A case of COPD at an early age (< 40) in a nonsmoker who has bullae at the bases of the lungs.

Answer 15

Alpha-1 antitrypsin deficiency

Question 17

Diagnosis: Decreased TLC, Decreased RV, Decreased VC, Normal FEV₁, Normal FEV₁/FVC ratio, Normal DL_CO

Answer 17

Extra-parenchymal (extra-thoracic) restriction

• Kyphosis
• Obesity

Question 18

Diagnosis: Increased TLC, Increased RV, Decreased FEV₁, Decreased FVC, Decreased FEV₁/FVC ratio, Decreased DL_CO

Answer 18

COPD

Question 19

Diagnosis: Normal or Increased TLC, Normal or Increased RV, Decreased FEV1, Decreased FVC, Normal or Decreased FEV1/FVC ratio, Normal or Increased DLCO

Answer 19

Asthma

Question 20

Diagnosis: Decreased TLC, Decreased RV, Decreased FEV₁, Decreased FVC, Normal or Increased FEV₁/FVC ratio, Decreased DL_CO

Answer 20

Fibrotic (or Interstitial Lung) Disease

Question 21

List the minimum that should be done for all patients with shortness of breath (SOB)

Answer 21

Oxygen

Continuous oximeter

Chest X-ray

Arterial blood gas (ABG)

Question 22

Causes of low DL_CO

Answer 22

Emphesema

Pneumonectomy

Interstitial lung disease

pulmonary embolism

Pulmonary HTN

Question 23

Arterial blood gases measurements

Answer 23

pH: 7.35 to 7.45

PCO₂: 33-45mmHg

PO₂: 75-105mmHg

Question 24

What is A-a gradient?

Answer 24

A-a gradient is alveolar-arterial gradient (PAO₂-PaO₂ gradient). It is a useful calculation for the assessment of oxygenation. A-a gradient increases with age and is only valid in room air. It is calculated as follows:

PA0₂-Pa0₂ gradient = 150 - 1.25 X PaCO₂ - PaO₂

i.e.,

A-a gradient = [150 - (1.25 X PaCO₂) - PaO₂]

This gradient is between 5 and 15 mmHg in normal young adults. It increases with all causes of hypoxemia except hypoventilation and high altitude

Question 25

Chest X-ray signs in pulmonary embolism

Answer 25

14% Normal
68% Atelectasis or parenchymal density
48% Pleural Effusion
35% Pleural based opacity
24% Elevated diaphragm
15% Prominent central pulmonary artery
7% Westermark’s sign
7% Cardiomegaly
5% Pulmonary edema