A 55-year-old man comes to the office due to fatigue and inability to maintain satisfactory erections during intercourse. He has also noticed decreased early-morning erections and sexual desire. The patient has had no headaches, visual symptoms, polyuria, head injuries, or motor weakness. He has been trying to lose weight with diet and exercise. Medical history is notable for prediabetes, hypertension, and hypertriglyceridemia, and current medications include lisinopril, atorvastatin, and aspirin. The patient's father had type 2 diabetes mellitus and died of sudden cardiac arrest at age 74; his sister has hypothyroidism. He lives with his wife and 20-year-old son.
Blood pressure is 142/74 mm Hg and pulse is 78/min. BMI is 38 kg/m². Body and facial hair distribution is normal. Visual fields are normal on confrontation. Testes are normal in size but have a soft consistency. The remainder of the physical examination is normal.
Laboratory results are as follows:
Which of the following is the best next step in evaluation of this patient's symptoms?

Question

A 55-year-old man comes to the office due to fatigue and inability to maintain satisfactory erections during intercourse. He has also noticed decreased early-morning erections and sexual desire. The patient has had no headaches, visual symptoms, polyuria, head injuries, or motor weakness. He has been trying to lose weight with diet and exercise. Medical history is notable for prediabetes, hypertension, and hypertriglyceridemia, and current medications include lisinopril, atorvastatin, and aspirin. The patient's father had type 2 diabetes mellitus and died of sudden cardiac arrest at age 74; his sister has hypothyroidism. He lives with his wife and 20-year-old son.
Blood pressure is 142/74 mm Hg and pulse is 78/min. BMI is 38 kg/m². Body and facial hair distribution is normal. Visual fields are normal on confrontation. Testes are normal in size but have a soft consistency. The remainder of the physical examination is normal.
Laboratory results are as follows:

Which of the following is the best next step in evaluation of this patient's symptoms?

Quizplus · Accepted Answer

11ec193a_97cf_85e4_853d_f1325edb544c_MD0002_00 This patient has symptoms (ie, decreased libido, possible early testicular atrophy) that warrant testing for hypogonadism. His loss of early-morning (nonsexual) erections suggests an organic (rather than psychogenic) cause of erectile dysfunction. Hypogonadism is common in men with obesity and/or diabetes/prediabetes, likely due to dysfunction of the hypothalamic pituitary axis. Other specific features that should prompt evaluation for androgen deficiency include loss of body hair, gynecomastia, hot flashes, and an unexplained decrease in bone density. In contrast, nonspecific symptoms (eg, fatigue, weakness, weight changes) alone do not warrant testing in most cases. The initial step in evaluation of male hypogonadism is a morning serum total testosterone level. However, testosterone shows significant variability, and low levels should be confirmed on repeat testing. (Choice A) Although obesity and diabetes are associated with true hypogonadism, these conditions are also associated with decreased levels of sex hormone-binding globulin, leading to spuriously low total testosterone levels. If the initial total testosterone level is low, measurement of free testosterone levels should be considered to confirm true hypogonadism in patients with these conditions; however, testing is not recommended in the initial workup of hypogonadism because it requires specialized assays that can be expensive and inaccurate and are not always readily available. (Choices B and C) If testosterone is low, serum FSH and LH levels can distinguish primary (elevated LH and FSH) from secondary (low/normal FSH and LH) hypogonadism. MRI of the pituitary should be considered in patients with secondary hypogonadism and for those with severe hypogonadism (eg, testosterone <150 ng/mL), deficiencies of additional pituitary hormones (eg, TSH, growth hormone), hyperprolactinemia, or mass effect symptoms (eg, visual field defects). (Choice D) Nocturnal penile tumescence can be useful in differentiating psychogenic (normal) and organic (reduced tumescence) causes of erectile dysfunction. However, it is not commonly used in clinical practice, and the decreased morning erections in this patient suggest an organic cause. Educational objective: Clinical features that warrant evaluation for androgen deficiency include decreased libido, erectile dysfunction, testicular atrophy, loss of body hair, gynecomastia, hot flashes, and an unexplained decrease in bone density. Nonspecific symptoms (eg, fatigue, weakness, weight changes) alone do not warrant testing in most cases. The initial step is a morning serum testosterone level, and low levels should be confirmed on repeat testing. __________ References: Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline. (http://www.ncbi.nlm.nih.gov/pubmed/20525905)

A 55-Year-Old Man Comes to the Office Due to Fatigue