Diagnosis and Management of Hyperprolactinemia-Induced Hypogonadism

Diagnosis

The European Association of Urology recommends that a male presenting with elevated prolactin and low testosterone has secondary (hypogonadotropic) hypogonadism caused by hyperprolactinemia, which requires immediate evaluation for a pituitary adenoma (prolactinoma) and treatment with dopamine agonist therapy, specifically cabergoline 1, 2
Secondary hypogonadism results from impairment of the hypothalamic-pituitary-gonadal (HPG) axis, where elevated prolactin suppresses gonadotropin-releasing hormone (GnRH) pulsatile secretion, leading to decreased LH and FSH, which in turn causes low testosterone production 1
The diagnostic workup should include confirmation of the hormonal pattern, with low testosterone (typically <300 ng/dL on two morning measurements between 8-10 AM) 3, 4
The American Urological Association suggests that low or low-normal LH and FSH levels should also be confirmed 5, 4
Elevated serum prolactin should be confirmed with repeat measurement to exclude spurious elevation 4

Pituitary MRI is mandatory for persistently elevated prolactin levels to evaluate for prolactinoma (micro- or macroadenoma) 5, 3
Men with testosterone <150 ng/dL and low/normal LH should undergo pituitary MRI regardless of prolactin levels, as non-secreting adenomas may also be present 4
The European Society of Endocrinology recommends reviewing medications that can cause hyperprolactinemia (antipsychotics, opiates, progestogens) 1, 2
Measuring serum iron saturation to exclude hemochromatosis is also recommended 3

The Endocrine Society suggests that cabergoline is the preferred dopamine agonist for treating prolactinomas and hyperprolactinemia-induced hypogonadism in men, achieving prolactin normalization in approximately 80% of men 1, 2
Testosterone replacement therapy should NOT be used as monotherapy in men interested in fertility, as it suppresses spermatogenesis 5
If testosterone replacement is needed after cabergoline treatment, transdermal preparations (gel, patch) are generally preferred for stable daily levels 3
The American College of Endocrinology recommends monitoring testosterone levels 2-3 months after initiation and every 6-12 months once stable 3