If TSH levels are elevated, hyperprolactinemia is secondary to hypothyroidism and treated accordingly. If TSH levels are normal, an MRI or CT scan is conducted to assess for any pituitary adenomas. Although hyperprolactinemia is often uncommon in postmenopausal women, prolactinomas detected after menopause are typically macroadenomas. While a plain X-ray of the bones surrounding the pituitary may reveal the presence of a large macroadenoma, small microadenomas will not be apparent. Magnetic resonance imaging (MRI) is the most sensitive test for detecting pituitary tumors and determining their size. MRI scans may be repeated periodically to assess tumor progression and the effects of therapy. Computed Tomography (CT scan) is another indicator of abnormalities in pituitary gland size; it also gives an image of the pituitary, but is less sensitive than the MRI. In addition to assessing the size of the pituitary tumor, physicians also look for damage to surrounding tissues, and perform tests to assess whether production of other pituitary hormones are normal. Depending on the size of the tumor, physicians may request an eye exam that includes the measurement of visual fields.However, a high measurement of prolactin may also result from the presence of macroprolactin, otherwise known as big prolactin or big-big prolactin, in the serum. Macroprolactin occurs when prolactin polymerizes together and can bind with IgG to form complexes. Although this can result in high prolactin levels in some assay tests, macroprolactin is biologically inactive and will not cause symptoms typical of hyperprolactinemia.
Particularly, antipsychotics have been linked to a majority of non-tumor related hyperprolactinemia cases due to their prolactin-rising and prolactin-sparing mechanisms. Typical antipsychotics have been shown to induce significant, dose-dependent increases in prolactin levels up to 10-fold the normal limit. Atypical antipsychotics vary in their ability to elevate prolactin levels, however, medications in this class such as risperidone and paliperidone carry the highest potential to induce hyperprolactinemia in a dose-dependent manner similar to typical antipsychotics. Signs and symptoms
In women, high blood levels of prolactin are typically associated with hypoestrogenism, anovulatory infertility, and changes in menstruation. Menstruation disturbances experienced in women commonly manifests as amenorrhea or oligomenorrhea. In the latter case, irregular menstrual flow may result in abnormally heavy and prolonged bleeding (menorrhagia). Women who are not pregnant or nursing may also unexpectedly begin producing breast milk (galactorrhea), a condition that is not always associated with high prolactin levels. For instance, many premenopausal women experiencing hyperprolactinemia do not experience galactorrhea and only some women who experience galactorrhea will be diagnosed with hyperprolactinemia. Thus, galactorrhea may be observed in individuals with normal prolactin levels and does not necessarily indicate hyperprolactinemia. This phenomenon is likely due to galactorrhea requiring adequate levels of progesterone or estrogen to prepare the breast tissue. Additionally, some women may also experience loss of libido and breast pain, particularly when prolactin levels rise initially, as the hormone promotes tissue changes in the breast.In men, the most common symptoms of hyperprolactinemia are decreased libido, sexual dysfunction, erectile dysfunction/impotence, infertility, and gynecomastia.