A 65-year-old man comes to the office with a 1-year history of erectile dysfunction and decreased libido. He has hypertension that was diagnosed 5 years ago and is controlled with diet. The patient has no history of cardiac problems, unexpected weight loss, visual changes, or symptoms of neuropathy. Family history is unremarkable. On examination, there is minimal bilateral gynecomastia without galactorrhea. Genitourinary examination shows decreased testicular size. The remainder of the physical examination, including visual fields on confrontation, is unremarkable. Laboratory results are as follows: Repeat early-morning testosterone level is 162 ng/dL. Which of the following is the best next step in management of this patient?

Question

A 65-year-old man comes to the office with a 1-year history of erectile dysfunction and decreased libido.  He has hypertension that was diagnosed 5 years ago and is controlled with diet.  The patient has no history of cardiac problems, unexpected weight loss, visual changes, or symptoms of neuropathy.  Family history is unremarkable.  On examination, there is minimal bilateral gynecomastia without galactorrhea.  Genitourinary examination shows decreased testicular size.  The remainder of the physical examination, including visual fields on confrontation, is unremarkable.  Laboratory results are as follows:  Repeat early-morning testosterone level is 162 ng/dL.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d3c8_02eb_bc81_0d9a1b9505f3_MD0003_00 This patient has gynecomastia and testicular atrophy. His laboratory results show low testosterone levels and inappropriately low/normal gonadotropin (ie, LH, FSH) levels, indicating secondary (central) hypogonadism. Low levels of testosterone normally increase LH and FSH levels due to loss of feedback inhibition; therefore, low or even normal LH and FSH levels suggest an inappropriate hypothalamic-pituitary response. Secondary hypogonadism can be due to mass lesions in the hypothalamus or pituitary, hyperprolactinemia (due to suppression of gonadotropin-releasing hormone), long-term use of glucocorticoids or opiates, or severe systemic illness. Secondary hypogonadism is also more common in individuals with obesity or type 2 diabetes mellitus. Patients with secondary hypogonadism should have measurement of serum prolactin. In men with prolactinoma, gynecomastia is present only in approximately one third of patients, and galactorrhea is uncommon. Visual field defects are present only when the tumor impinges on the optic chiasm. Patients should also have screening for other pituitary hormone deficiencies (eg, TSH). Pituitary imaging with MRI is indicated for patients with elevated prolactin, mass-effect symptoms (eg, visual field defects), very low (<150 ng/dL) testosterone levels, or disruptions in other pituitary hormones. suppression of gonadotropin-releasing hormone (Choice A) Angiography of the penile deep arteries may be indicated when a vascular etiology of erectile impotence is suspected. However, this test is invasive and not routinely performed. (Choice C) Hemochromatosis should be suspected when hypogonadism is associated with abnormal skin pigmentation, diabetes mellitus, elevated liver enzymes, and arthropathy. It is unlikely that this patient has hemochromatosis considering the absence of a positive family history, his age at presentation, and the lack of other clinical features. (Choice D) Phosphodiesterase type 5 inhibitors (eg, sildenafil) are useful in patients with erectile dysfunction due to a variety of causes. However, symptomatic treatment may not be needed if a correctable cause is found. (Choice E) Testosterone therapy may be required if serum prolactin and MRI of the pituitary are normal. Dopaminergic agonists are the preferred therapy for prolactinoma. Educational objective: Secondary hypogonadism can be due to mass lesions in the hypothalamus or pituitary, hyperprolactinemia, long-term use of glucocorticoids or opiates, or severe systemic illness. Patients should have measurement of serum prolactin and screening for other pituitary hormone deficiencies. Pituitary imaging is indicated for patients with elevated prolactin, mass-effect symptoms, very low testosterone levels, or disruptions in other pituitary hormones. References: Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline. (http://www.ncbi.nlm.nih.gov/pubmed/20525905) Update: hypogonadotropic hypogonadism in type 2 diabetes and obesity. (http://www.ncbi.nlm.nih.gov/pubmed/21896895)

A 65-Year-Old Man Comes to the Office with a 1-Year