Hyperprolactinemia can be caused by physiological, pathological, or drug-related problems. Physiological causes include pregnancy, exercise, stress, seizures, and many others. Pathological causes are further categorized as pituitary diseases, hypothalamic diseases, pharmacologic causes, and systemic disorders. An example of pituitary disease is prolactinoma and acromegaly. Hypothalamic diseases include craniopharyngioma and granuloma. 

Less than 1% of people in the general population have hyperprolactinemia. Most people with hyperprolactinemia have prolactinoma, which is a benign tumor that makes prolactin. Prolactinoma happens to about 30 out of every 100,000 women.

Hyperprolactinemia causes problems with reproduction and a condition called galactorrhea. There is a possibility of growth stop, delayed pubertal development, and primary amenorrhea in children and adolescents.

Anyone can experience the following symptoms:

• Infertility;
• Less interest in sex;
• Low bone mass;
• Having milk discharges even when not pregnant;
• Changes in menstruation that are not caused by menopause, such as periods that come and go or none at all (amenorrhea);
• Pain or discomfort during sex.

Doctors will measure prolactin levels during the midmorning hours and in the fasting state. The average basal level of prolactin in women is 13 ng/ml. In most labs, the highest normal level of prolactin in the blood is between 15 and 20 ng/ml. Hyperprolactinemia is when the amount of prolactin in the blood is above the upper limit.

If serum prolactin is high, the next step is to find out why in the order below. Doctors will first find out if there are any physical and pharmacological causes. They will also conduct imaging of the hypothalamus and pituitary glands. Depending on the signs and symptoms, doctors might also order the following labs; 

• Thyroid function test
• Renal function test
• Insulin-like growth factor-1 (IGF-1)
• Adrenocorticotropic hormone (ACTH)
• Luteinizing hormone (LH)
• Follicle-stimulating hormone (FSH).

Treatment

Hyperprolactinemia treatment is condition-specific and depends on the underlying reason. Some patients with high prolactin levels may not need treatment because they have few or no symptoms.

Prolactinomas are the most prevalent cause of hyperprolactinemia, however they can be treated in several ways. Dopamine agonists reduce prolactin levels and can decrease tumors in people with prolactinoma. If the prolactinoma does not respond to medicine, surgical removal may be necessary. If drugs and/or surgery are ineffective in lowering prolactin levels, radiation therapy is the last resort.

Unfortunately, hyperprolactinemia is unavoidable. The single known risk factor for prolactinoma, the most common cause of hyperprolactinemia, is MEN type 1. If a sibling or parent has this problem, you may desire genetic testing. This may help detect prolactinoma early.

References

Thapa S, Bhusal K. Hyperprolactinemia. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537331/

Cleveland Clinic (2022). Hyperprolactinemia. Retrieved November 22, 2022, from https://my.clevelandclinic.org/health/diseases/22284-hyperprolactinemia