American Board of Internal Medicine (ABIM) Certification Practice Exam

What effect does polycythemia have in the context of COPD and long-term oxygen therapy?

1. Increases risk of lung cancer

2. If combined with hypoxemia, indicates the need for therapy

3. Indicates sufficient oxygenation

4. Requires immediate blood transfusion

The correct answer is: If combined with hypoxemia, indicates the need for therapy

Polycythemia, which is characterized by an increased production of red blood cells, can occur in patients with chronic obstructive pulmonary disease (COPD) as a compensatory mechanism in response to chronic hypoxemia. In the context of COPD, the presence of polycythemia often signifies that the body is struggling to get enough oxygen. When polycythemia is detected alongside hypoxemia, it serves as an important clinical indicator of significant oxygen deficiency. This combination suggests the need for long-term oxygen therapy to alleviate the hypoxemia and, consequently, reduce the risk of complications associated with chronic low oxygen levels, such as further cardiovascular strain and worsening pulmonary hypertension. Providing supplemental oxygen can help improve oxygen saturation levels, decrease erythropoietin stimulation from hypoxia, and ultimately alleviate the polycythemia. In terms of the other choices provided, the development of polycythemia in the context of COPD does not inherently increase the risk of lung cancer, nor does it indicate that there is sufficient oxygenation. Immediate blood transfusion is not a standard treatment for polycythemia in this scenario, as the focus is generally on addressing the underlying hypoxemia rather than simply adjusting red blood cell levels. Therefore, the correct response