The correct answer is B. This patient most likely has COPD, which includes emphysema and chronic bronchitis. Although many patients have features of emphysema and chronic bronchitis, they have separate features. This patient is described as the classic "pink-puffer" with emphysema. Patients with emphysema-type changes in the lung have irreversible permanent dilation of distal airspaces with cartilage destruction. Low diffusion capacity of the lung for carbon monoxide (DLCO) is expected in emphysema, whereas patients with chronic bronchitis have a normal DLCO. Emphysema leads to the destruction of vasculature in the alveolar septa which leads to a decreased diffusion of CO into the blood. This leads to an increased CO in the exhaled gas.
A bronchodilator response (choice A) is the finding of asthma. Chronic obstructive pulmonary disease is characterized by irreversible airway obstruction.
Patients with emphysema have air-trapping secondary to decreased elastic recoil in their lungs. This will show increased residual volume (choice C) and total lung capacity (choice D) .
The ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) is used to measure air movement in and out of the lungs. If this ratio is 80% of expected or less, a diagnosis of obstructive lung disease is suspected. Because our patient has an obstructive lung disease, we would expect FEV1/FVC to decrease, not increase (choice E) .
PEARL: Patients who present to a healthcare provider with a combination of chronic productive cough, dyspnea, and/or known inhalational exposure (tobacco, dust, chemicals, etc.) should be referred for pulmonary function testing (PFTs) for evaluation of possible COPD. PFTs will reveal an airflow obstruction with a FEV1/FVC ratio of less than 0.70 in COPD. The diffusing capacity of carbon monoxide (DLCO) is a nonsensitive and nonspecific test and therefore cannot be used to identify patients with mild COPD, but would be decreased in proportion to the severity of the emphysema in more severe cases.
PEARL: Learn how to recognize the typical presentation for emphysema: flattened diaphragm, small heart, hyperinflated lungs, and pursued-lips breathing.
- Patients with emphysema-type changes in the lung have irreversible permanent dilation and destruction of distal air spaces, which will explain a low diffusion capacity of the lung for carbon monoxide (DLCO). Patients with chronic bronchitis have a normal DLCO.
