A 52-year-old man comes to the office due to progressive erectile dysfunction and loss of libido for the last 8 months. He is unable to obtain an erection and also has malaise and poor energy. The patient has no history of headaches, visual loss, anabolic steroid use, daytime sleepiness, or prior testicular injury. His other medical problems include type 2 diabetes mellitus, hypertension, and hyperlipidemia. Medications include metformin, atorvastatin, and ramipril. The patient is married and has 2 children.
Blood pressure is 120/80 mm Hg and pulse is 66/min. BMI is 31 kg/m². The patient has normal secondary sexual characteristics without gynecomastia. Peripheral vision is intact on confrontation testing. The testes are normal in size with a soft consistency. The remainder of the physical examination is normal.
Laboratory results are as follows:
Repeat serum testosterone is 136 ng/dL, with serum FSH of 5 mU/mL, LH of 4 mU/mL, and prolactin of 10 ng/mL. Which of the following is the most appropriate next step in addressing this patient's current condition?

Question

A 52-year-old man comes to the office due to progressive erectile dysfunction and loss of libido for the last 8 months. He is unable to obtain an erection and also has malaise and poor energy. The patient has no history of headaches, visual loss, anabolic steroid use, daytime sleepiness, or prior testicular injury. His other medical problems include type 2 diabetes mellitus, hypertension, and hyperlipidemia. Medications include metformin, atorvastatin, and ramipril. The patient is married and has 2 children.
Blood pressure is 120/80 mm Hg and pulse is 66/min. BMI is 31 kg/m². The patient has normal secondary sexual characteristics without gynecomastia. Peripheral vision is intact on confrontation testing. The testes are normal in size with a soft consistency. The remainder of the physical examination is normal.
Laboratory results are as follows:

Repeat serum testosterone is 136 ng/dL, with serum FSH of 5 mU/mL, LH of 4 mU/mL, and prolactin of 10 ng/mL. Which of the following is the most appropriate next step in addressing this patient's current condition?

Quizplus · Accepted Answer

11ec193a_97b6_f49d_853d_d3395bbd7085_MD0002_00 This patient has hypogonadal symptoms with a low serum testosterone level and low/inappropriately normal FSH and LH levels. This is consistent with hypogonadotropic (central) hypogonadism. Hypogonadism is common in men with type 2 diabetes, especially those age >65 or with concurrent obesity. For this reason, some experts have recommended regular screening with serum testosterone in patients with diabetes. Older (ie, age >65) obese men with type 2 diabetes typically have low-normal to mildly low serum testosterone levels (200-300 ng/dL) due to decreased gonadotropin release from the anterior pituitary (likely obesity mediated), as well as physiologic changes in testosterone metabolism (eg, decreased sex hormone-binding globulin). These patients do not need pituitary imaging. However, younger men with more pronounced declines in serum testosterone (as in this patient) and/or abnormalities in additional pituitary hormones (eg, central hypothyroidism) are more likely to have sellar masses or other structural disruptions of the hypothalamic-pituitary axis (eg, infiltrative disease). These patients should have pituitary imaging, preferably with MRI. (Choice A) Although this patient's glycemic control is not optimal, it has not been shown that better control can mitigate hypogonadal symptoms. In addition, treatment of hypogonadism is associated with increased insulin sensitivity in type 2 diabetes. Once the diagnostic evaluation is complete, the patient's glycemic control can be re-evaluated. (Choice B) Nocturnal penile tumescence studies can differentiate psychogenic erectile dysfunction from "organic" causes (eg, vascular, neurologic) of impotence. Since this patient has low testosterone levels, an organic cause for his erectile dysfunction is more likely than a psychogenic cause. (Choice D) Nerve conduction studies can evaluate for autonomic neuropathy, which can cause erectile dysfunction. However, autonomic neuropathy would not cause low testosterone levels. (Choice E) This patient may eventually need testosterone replacement therapy, but he should first undergo etiologic evaluation prior to treatment. Educational objective: Patients with type 2 diabetes and obesity commonly have hypogonadotropic hypogonadism with borderline low testosterone levels (200-300 ng/dL) and do not routinely need pituitary imaging. However, patients with markedly low serum testosterone levels or abnormalities of additional pituitary hormones are more likely to have a pituitary mass and warrant pituitary MRI. __________ References: Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline. (http://www.ncbi.nlm.nih.gov/pubmed/20525905) Hypogonadism, erectile dysfunction, and type 2 diabetes mellitus: what the clinician needs to know. (http://www.ncbi.nlm.nih.gov/pubmed/21084793)

A 52-Year-Old Man Comes to the Office Due to Progressive