A 64-year-old man comes to the office for routine follow-up. He has a history of chronic obstructive pulmonary disease and notes mild dyspnea when walking long distances or ascending several flights of stairs, which is unchanged from his previous visits. Six months ago, the patient was diagnosed with testosterone deficiency after work-up for fatigue and decreased libido revealed low serum testosterone levels. He was initiated on injectable testosterone replacement therapy and notes a significant improvement in his symptoms. Other medical problems include hypertension and gastroesophageal reflux. The patient is an ex-smoker with a 20-pack-year history.
Blood pressure is 126/78 mm Hg and pulse is 72/min. Oxygen saturation while breathing ambient air is 96% at rest and 90% after several minutes of walking. Breath sounds are distant with no wheezing. Heart sounds are normal. The abdomen is soft and nontender. Prostate size is normal.
Laboratory results are as follows:
Which of the following is the most appropriate next step in management of this patient?

Question

A 64-year-old man comes to the office for routine follow-up.  He has a history of chronic obstructive pulmonary disease and notes mild dyspnea when walking long distances or ascending several flights of stairs, which is unchanged from his previous visits.  Six months ago, the patient was diagnosed with testosterone deficiency after work-up for fatigue and decreased libido revealed low serum testosterone levels.  He was initiated on injectable testosterone replacement therapy and notes a significant improvement in his symptoms.  Other medical problems include hypertension and gastroesophageal reflux.  The patient is an ex-smoker with a 20-pack-year history.
Blood pressure is 126/78 mm Hg and pulse is 72/min.  Oxygen saturation while breathing ambient air is 96% at rest and 90% after several minutes of walking.  Breath sounds are distant with no wheezing.  Heart sounds are normal.  The abdomen is soft and nontender.  Prostate size is normal.
Laboratory results are as follows:
 Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Approximately 25% of men on testosterone therapy develop secondary polycythemia (hemoglobin >16.5 g/dL) due to testosterone-induced elevations in erythropoietin (EPO) and reductions in hepcidin. Polycythemia develops in a dose dependent manner and can be associated with venous thromboembolism and cardiovascular events. As such, patients on testosterone therapy require hematocrit monitoring; testosterone supplementation should be decreased/discontinued if hematocrit levels are >54%. (Choices A and E) Hypoxia is another common cause of secondary polycythemia as oxygen desaturations <92% increase circulating EPO levels. Although this patient's exercise-induced oxygen desaturations could potentially cause secondary polycythemia, his pulse oxymetry levels are above the threshold (≤88%) for long-term oxygen therapy. In addition, he has no clear indicators (eg, snoring, daytime somnolence, morning headaches, obesity) of obstructive sleep apnea that would necessitate an overnight oxygen saturation study. The best next step is to reduce or discontinue testosterone supplementation to see if the polycythemia improves. (Choices C and D) Primary polycythemia (EPO-independent) is most commonly due to polycythemia vera, a chronic myeloproliferative disorder characterized by polycythemia with or without other manifestations (eg, aquagenic pruritus, erythromelalgia, thrombosis, hemorrhage). Serum EPO levels are usually low, and JAK2 mutation testing is usually (>97%) positive. This patient who was recently initiated on testosterone supplementation should have his testosterone therapy reduced or discontinued prior to considering additional work-up. Educational objective: Approximately 25% of men on testosterone therapy develop polycythemia (hemoglobin >16.5 g/dL). Polycythemia can be associated with venous thromboembolism and cardiovascular complications. Therefore, patients require hematocrit monitoring; if levels exceed 54%, testosterone should be reduced or discontinued. __________

A 64-Year-Old Man Comes to the Office for Routine Follow-Up