What is Hyperprolactinemia?
Hyperprolactinemia is a medical condition characterized by elevated prolactin levels in the serum. Prolactin is a hormone secreted by the pituitary gland, a structure that sits underneath the brain in a region called the sella turcica. Elevated prolactin levels may occur due to normal processes of the body such as pregnancy, nipple stimulation, and stress. However, conditions such as pituitary tumors (eg, prolactinoma) or use of certain medications can also lead to increased serum prolactin levels and its manifestations.
Women with hyperprolactinemia often develop menstrual irregularities, infertility, and mild letdown from the breast. Men often have decreased libido, erectile dysfunction, and breast enlargement (gynecomastia). Patients with prolactinoma may develop a headache and visual changes due to tumor enlargement and nerve compression.
What Causes Hyperprolactinemia?
Hyperprolactinemia can be caused by normal physiologic processes or pathologic conditions. Normal conditions that lead to elevated prolactin levels typically include pregnancy, nipple stimulation, and stress.
Pathologic conditions associated with hyperprolactinemia typically include pituitary adenoma (prolactinoma) or the use of drugs that block dopamine receptors. Dopamine (prolactin-inhibitory factor) normally inhibits the release of prolactin from the pituitary gland – therefore, drugs that block dopamine consequently result in increased prolactin levels.
The most common drugs implicated in hyperprolactinemia include antipsychotics such as risperidone and haloperidol. Antiemetic medications such as metoclopramide can also increase prolactin. Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine and paroxetine may also contribute to hyperprolactinemia.
How Common is Hyperprolactinemia?
Hyperprolactinemia is relatively uncommon in the United States. The condition may require referral to an endocrinology or neurosurgery specialist, especially if first-line measures are unsuccessful.
Hyperprolactinemia affects <1% of the general population in the United States. About 5%-14% of individuals evaluated for secondary amenorrhea (absence of menstrual periods) have hyperprolactinemia. One of the most common causes of the condition is pituitary adenomas (prolactinomas), which account for about 30%-40% of pituitary tumors. The diagnosis of prolactinoma is more commonly made in women compared to men, and typically occurs around age 20-40.
Signs and Symptoms
The symptoms and signs of hyperprolactinemia depend on your gender. If you are a woman, your symptoms also depend on whether or not you have had menopause. Some of the symptoms of hyperprolactinemia overlap between men and women.
In men, hyperprolactinemia typically causes the following symptoms:
- Decreased libido – loss of sexual desire
- Erectile dysfunction
- Gynecomastia – breast enlargement
The symptoms of hyperprolactinemia in premenopausal women typically include:
- Abnormal menstruation – oligo- or amenorrhea
- Galactorrhea – mild letdown from breasts
Patients with large prolactinoma may develop headache and impaired vision due to tumor expansion and compression over the optic chiasm. The optic chiasm is a nerve structure located near the sella turcica and pituitary gland – this structure is critical for normal vision. Pituitary tumors can expand, injuring these nerves and resulting in loss of peripheral vision.
Headache and visual changes may be the only manifestation of hyperprolactinemia in postmenopausal women as these individuals do not have menstrual periods and are already infertile. Sometime a pituitary tumor is detected incidentally on brain MRI.
The diagnosis of hyperprolactinemia is suggested based on the patient’s history, symptoms, and physical examination, but typically confirmed with laboratory and imaging studies.
Your doctor will usually obtain a serum prolactin level. If this test is elevated, this may suggest pregnancy, a medication side effect, or pituitary adenoma. Your doctor will likely want to obtain other pituitary hormone levels such a growth hormone and thyroid stimulating hormone (TSH). They may order a urine pregnancy test if you are a woman of childbearing age.
Patients with confirmed hyperprolactinemia often undergo brain MRI to evaluate for pituitary tumors such as prolactinoma. Additional blood tests commonly include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), and thyroid function studies (TSH, free T4).
Hyperprolactinemia Medication and Treatment
Hyperprolactinemia is typically treated by tapering, discontinuing, or switching any implicated medications such antipsychotics (eg, haloperidol) or antiemetics (eg, metoclopramide). Patients with pituitary adenomas (prolactinomas) typically benefit from initial treatment with dopamine agonists such as Dostinex (cabergoline). Dopamine agonists are effective because they inhibit the release of prolactin from the pituitary gland.
Patients who fail to respond to cabergoline may benefit from transsphenoidal surgery to remove the prolactinoma. This is also true in patients with large prolactinomas that produce symptoms related to brain compression such as headache and visual changes. Radiation therapy may also be required after tumor resection to prevent regrowth of residual adenoma.
- Molitch ME. Drugs and prolactin. Pituitary 2008; 11:209. - https://www.ncbi.nlm.nih.gov/pubmed/18404390
- Bayrak A, Saadat P, Mor E, et al. Pituitary imaging is indicated for the evaluation of hyperprolactinemia. Fertil Steril 2005; 84:181. - https://www.ncbi.nlm.nih.gov/pubmed/16009175
- Casanueva FF, Molitch ME, Schlechte JA, et al. Guidelines of the Pituitary Society for the diagnosis and management of prolactinomas. Clin Endocrinol (Oxf) 2006; 65:265. -https://www.ncbi.nlm.nih.gov/pubmed/16886971
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.