A 66-year-old man comes to the office to discuss his sexual health. He thinks that he has symptoms of low testosterone, similar to those described in an article he recently read in a health magazine. The patient has normal sexual desire but reduced spontaneous erections and reduced semen volume with ejaculation. He requires more stimulation to achieve a satisfactory erection and has a longer sexual refractory period than before. The patient has no known medical conditions and takes no medications. He does not use tobacco, alcohol, or illicit drugs. Vital signs are normal. BMI is 24.5 kg/m². Physical examination, including examination of the testes, is normal. After laboratory testing is completed, the physician finds no evidence of organic disease and concludes that the results are consistent with normal aging. Compared to a healthy young man, which of the following sets of test results would be most consistent with the physician's conclusion?

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Quizplus · Accepted Answer

11ec160b_3ca8_0c05_9249_53e174922be3_MD0001_00 Unlike women, who typically experience a precipitous drop in sex hormone levels at menopause, men generally experience slower, more variable declines with aging. Typical findings seen in normal aging include the following: Compared to women of similar age, men often report higher levels of sexual functioning, activity, and satisfaction as they age. However, men commonly experience mild, nonspecific changes in sexual function, including the following: At very advanced age (eg, >80), very low testosterone levels can lead to specific hypogonadal symptoms (eg, loss of libido, erectile failure). However, this patient has nonspecific symptoms that are common in aging and do not suggest underlying gonadal failure. (Choice B) Certain synthetic androgen analogues (eg, danazol) and progestins (eg, levonorgestrel) can displace testosterone from SHBG, increasing free testosterone without a significant change in SHBG levels. However, this pattern is not seen in normal aging. (Choice C) SHBG levels are suppressed in patients with insulin resistance, diabetes, and obesity. If the pituitary-gonadal axis is intact, total testosterone levels are reduced, but free testosterone levels are relatively preserved. However, this patient has a normal weight, and SHBG is likely increased at age 66. (Choice D) Testosterone suppresses SHBG synthesis. Excessive, unregulated testosterone (eg, exogenous androgen abuse) would usually be associated with low SHBG levels, but these values would not be seen in normal aging. (Choice E) Hyperthyroidism often causes increased production of SHBG independent of age; total testosterone increases to saturate the increased steroid hormone-binding sites, and free testosterone is unchanged. Although this patient likely has increased SHBG levels, his total and free testosterone levels are more likely decreased due to the effects of aging. Educational objective: Normal aging in men is associated with a slow decline in gonadal testosterone production, a compensatory rise in LH, and rising serum levels of sex hormone-binding globulin. Common, nonspecific symptoms include decreased ejaculate volume, increased erectile latency and sexual refractory time, and moderately impaired erectile function. __________ References: Endocrinology of the aging male. (http://www.ncbi.nlm.nih.gov/pubmed/21397200)

A 66-Year-Old Man Comes to the Office to Discuss His