Anemia 1

Question

Vignette: A 32-year-old woman comes to the physician because of increasing fatigue and shortness of breath over the past 6 months. She has no other medical problems, but notes that her symptoms worsen with exercise and improve with rest. Her physical examination reveals pale conjunctiva and a systolic ejection murmur. Her hemoglobin level is 9 g/dL (normal: 11.5-15.5 g/dL). Based on her symptoms, the most likely alteration in her cardiovascular physiology is which of the following?

Choices

A) Increased cardiac output

B) Increased systemic vascular resistance

C) Decreased cardiac output

D) Decreased systemic vascular resistance

E) Increased heart rate

Answer

A) Increased cardiac output

Explanation

This patient's anemia (evidenced by a low hemoglobin level and pale conjunctiva) and symptoms of fatigue and exercise intolerance suggest a chronic, compensated state of decreased oxygen-carrying capacity of the blood. In response to anemia, the body compensates by increasing cardiac output in order to deliver more blood to the tissues. This is achieved by increasing heart rate and stroke volume. The systolic ejection murmur heard in this patient is likely due to the increased blood flow across the aortic and pulmonic valves, which is a common finding in patients with high cardiac output states such as anemia. Decreased systemic vascular resistance would also increase cardiac output, but it would most likely be associated with conditions such as septic shock or liver cirrhosis, which are not indicated in this patient's presentation.