A 30-year-old man comes to the physician because of decreased sexual desire over the last 3 months. He says that he is otherwise healthy and has no other complaints. His other medical problems include hypercholesterolemia and migraine headaches. He was prescribed topiramate 4 months ago by his previous primary care physician for frequent headaches, but it did not seem to help much. He does not use tobacco or drink alcohol. He has a sedentary lifestyle and has gained 24 lbs (10.9 kg) in the past 3 years. His sister suffers from migraine headaches and his father had a myocardial infarction at the age of 45.
His blood pressure is 132/80 mm Hg and pulse is 72/min. The patient's body mass index (BMI) is 32 kg/m². Examination shows no gynecomastia or hepatomegaly. He has normal secondary sexual characteristics. His testes are normal in size and consistency. The remainder of the examination is within normal limits.
Laboratory results are as follows:

Which of the following is the most appropriate next step in management?

Question

A 30-year-old man comes to the physician because of decreased sexual desire over the last 3 months. He says that he is otherwise healthy and has no other complaints. His other medical problems include hypercholesterolemia and migraine headaches. He was prescribed topiramate 4 months ago by his previous primary care physician for frequent headaches, but it did not seem to help much. He does not use tobacco or drink alcohol. He has a sedentary lifestyle and has gained 24 lbs (10.9 kg) in the past 3 years. His sister suffers from migraine headaches and his father had a myocardial infarction at the age of 45.
His blood pressure is 132/80 mm Hg and pulse is 72/min. The patient's body mass index (BMI) is 32 kg/m². Examination shows no gynecomastia or hepatomegaly. He has normal secondary sexual characteristics. His testes are normal in size and consistency. The remainder of the examination is within normal limits.
Laboratory results are as follows:

Which of the following is the most appropriate next step in management?

Quizplus · Accepted Answer

11ec193a_97a9_fc30_853d_3952e6ace3bd_MD0002_00 11ec193a_97a9_fc31_853d_1bc5f5c095ae_MD0002_00 This patient presents with hypogonadotropic hypogonadism (secondary hypogonadism) based on his low testosterone and low LH levels. He was also diagnosed with migraine headaches; however, the treatment did not seem to help much. Most migraine diagnoses are made based on clinical features and without neuroimaging; hence, it is not uncommon to have an incorrect diagnosis. Given these findings, a macroprolactinoma should be considered. Men are more likely than women to present with headaches, visual disturbances, and hypogonadism at the time of diagnosis. In contrast to women, prolactinomas in men are usually large at the time of diagnosis, likely due to delayed diagnosis. hypogonadism The prolactin level usually correlates with the size of the prolactinoma. Dopaminergic agents (i.e., bromocriptine and cabergoline) are the preferred treatment for prolactinomas, even in large macroprolactinomas, since the treatment usually leads to a rapid decline in tumor size in most patients. (Choice A) Iron studies can diagnose hemochromatosis, which can cause hypogonadism and erectile dysfunction due to iron deposition in pituitary cells. However, this patient's young age, rapidity of symptom progression, new headaches, and absence of other clinical symptoms (e.g., hyperpigmented skin, weakness, lethargy) makes this less likely. His elevated liver enzymes are more likely due to non-alcoholic steatohepatitis secondary to weight gain. (Choice C) Severely obese individuals can have low total testosterone and low free testosterone due to decreased sex hormone binding globulin level. However, this patient has features of hypogonadism with headaches that warrants further investigation. (Choice D) Prolactinomas suppress gonadotropin secretion and leads to low testosterone. Treating the prolactinoma with bromocriptine or cabergoline will likely improve the testosterone levels and symptoms without the need for testosterone replacement therapy. (Choice E) Weight loss is a beneficial side effect of topiramate. However, topiramate does not cause low testosterone or hyperprolactinemia, and its discontinuation will likely not improve this patient's low testosterone. Topiramate can be discontinued if the patient is found to have a reason for his headaches other than migraines. Educational objective: Prolactinomas in men usually present with visual changes, headaches, and hypogonadism. They are typically larger at the time of diagnosis than they are in women (most often due to a delay in diagnosis). Diagnosis is confirmed with a serum prolactin level followed by brain MRI. __________ References: Pituitary tumors: The prolactinomas (http://www.ncbi.nlm.nih.gov/pubmed/19945024) Long-term efficacy of bromocriptine in macroprolactinomas and giant prolactinomas in men. (http://www.ncbi.nlm.nih.gov/pubmed/16379032) Gender-related differences in prolactinomas. A clinicopathological study. (http://www.ncbi.nlm.nih.gov/pubmed/15855888)

A 30-Year-Old Man Comes to the Physician Because of Decreased