Case of the Month: ESAP Special Edition

esap cover

This issue highlights a special edition of ESAP, available for a limited time. Test your clinical knowledge with this free case to discover the rich intellectual legacy of endocrinology. Available on the online store.

Clinical Vignette

A 62-year-old man is referred for assistance in the management of hyperprolactinemia and diminished libido. Over the past 9 months, he has experienced a steady reduction in his libido, which has resulted in tension with his wife. He sought medical attention from his primary care physician who elicited an additional history of erectile dysfunction. His total testosterone concentration was documented to be 291 ng/dL (10.1 nmol/L) (reference range, 300-900 ng/dL [10.4-31.2 nmol/L]). A subsequent prolactin measurement was 91 ng/mL (4.0 nmol/L) (reference range, 4-23 ng/mL [0.17-1.00 nmol/L]), and he was thus referred for further evaluation.

His medical history is notable for 24 years of moderate to poorly controlled type 2 diabetes mellitus, complicated by chronic renal insufficiency with a creatinine concentration of 2.1 mg/dL (185.6 µmol/L) (reference range, 0.7-1.3 mg/dL [61.9-114.9 mmol/L]). He is currently treated with sitagliptin, 25 mg daily, and glyburide, 2.5 mg daily. His most recent hemoglobin A1c level was 8.3% (67 mmol/mol) (reference range, 4.7%-5.8% [28-40 mmol/mol]). He has hypertension, which is treated with lisinopril, 20 mg daily. In addition, he has a history of depression that has been treated for the past 18 months with bupropion, 100 mg 3 times daily. He has had no headaches or vision changes.

On physical examination, his height is 72 in (182.9 cm) and weight is 188 lb (85.5 kg) (body mass index = 25.5 kg/m2). His blood pressure is 140/86 mm Hg, and pulse rate is 94 beats/min. Findings on genitourinary examination are normal, and he has mild bilateral pedal edema. Visual fields are full to confrontation. There is no evidence of gynecomastia.

You order a repeated prolactin measurement, which returns at 90 ng/mL (3.9 nmol/L).

Which of the following represents the most likely cause of this patient’s hyperprolactinemia?

  1. Pituitary macroprolactinoma
  2. Chronic renal insufficiency
  3. Lisinopril
  4. Sitagliptin
  5. Bupropion