Sandbox:Mydah

Associate Editor(s)-in-Chief: Mydah Sajid, MD[1]

Hyperprolactinemia resident survival guide

Overview

Hyperprolactinemia is defined as high circulating levels of prolactin in the blood. The cut-off values of serum prolactin for hyperprolactinemia are greater than 20 ng/ml in men and postmenopausal women and greater than 30ng/ml in premenopausal women. Prolactin hormone is produced by lactotroph cells located in the anterior lobe of the pituitary gland. It is responsible for lactation and the development of breasts in females during pregnancy. Elevated levels of prolactin cause galactorrhea, menstrual irregularities, and failure to conceive in females and erectile dysfunction, hypogonadism, and infertility in males. This section provides a short and straight to the point overview of the hyperprolactinemia.

Causes

Life-threatening Causes

Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated.

• Severe burns on the chest can cause hyperprolactinemia due to neural stimulation similar to suckling.

Common Causes

• Pregnancy
• Lactation
• Prolactinoma
• Injury to dopaminergic neurons in the hypothalamus (sarcoidosis, craniopharyngioma, and metastatic brain carcinoma)
• Section of the hypothalamic-pituitary stalk
• Antipsychotics (risperidone, haloperidol, and phenothiazine)
• Selective serotonin reuptake inhibitors
• Metoclopramide
• Domperidone
• Methyldopa
• Verapamil
• Familial hyperprolactinemia
• Hypothyroidism
• Chronic renal failure
• macroprolactinomas
• Exercise

Evaluation

Shown below is an algorithm summarizing the diagnosis of hyperprolactinemia according to an Endocrine Society Clinical Practice guidelines:

Characterize the symptoms headache oligomenorrhea infertility hypogonadism erectile dysfunction galactorrhea

Inquire about any present illness like hypothyroidism, chronic renal failure, and the use of medications known to cause hyperprolactinemia.

Measure serum prolactin. Elevated serum prolactin

Mesure serum TSH. TSH levels elevated?

Yes

No

Treat hypothyroidism

Perform the MRI with the contrast of the brain. Does it show any mass in the hypothalamic-pituitary region?

Levels of TSH and prolactin should be reassessed after 6-12 weeks.

Yes. The levels of other pituitary hormones should be evaluated: Plasma corticotropins (ACTH), Serum TSH, Insulin-like growth factors, Follicle-stimulating hormone, Luteinizing hormone, Estradiol/ Testosterone

No

Management

Shown below is an algorithm summarizing the treatment of hyperprolactinemia:

The prolactinoma are treated in the following patients: A macroadenoma causing neurological symptoms such as headache and visual impairment due to compression of the optic chiasm. Hypogonadism and galactorrhea due to increased prolactin secretion. Infertility in women with disrupted luteal phase.

The drug of choice for prolactinoma are dopamine agonists as they decrease prolactin secretion and reduce the size of the prolactinoma. Cabergoline is the preferred drug because of its efficacy and lower incidence of nausea and side effects compared to bromocriptine.

Transsphenoidal surgery is done in: Patients with unsuccessful treatment with dopamine agonists. A female patient with a known history of lactotroph macroadenoma who wishes to conceive. Transsphenoidal surgery has a high success rate in reducing serum prolactin to a normal level.

The preferred initial dose of cabergoline for microadenoma is 0.25mg twice a week or 0.5mg once a week. The medicine should be given at dinner or bedtime to reduce the incidence of nausea and drowsiness.

Do's

• “Hook effect” should be kept in consideration while assessing serum prolactin levels. Patients with macroadenoma can have artifactually low values of serum prolactin between 20 to 200 mcg/L in patients with high levels of serum prolactin i.e. 5000 mcg/L. This artifact is avoided by repeating the assay by dilution of serum.
• Cabergoline is preferred by women who wish to conceive as it is safe in early pregnancy. Though bromocriptine is also a safe choice with more evidence of reduced events of congenital defects.
• Patients with hyperprolactinemia with normal serum prolactin levels should be monitored for regular intervals after discontinuing cabergoline. There is a recurrence of hyperprolactinemia in these patients.

Don'ts

• Certain medications like risperidone, domperidone, methyldopa, metoclopramide, verapamil, and cimetidine raise serum prolactin levels. These medications can blunt the effects of dopamine agonists.
• The patients should be monitored for side effects. Cabergoline treatment in prolactinoma patients for more than three months can result in impulse control disorders. Hypersexuality is common in males and compulsive eating disorders in females.