What is Hyperprolactinemia?
Hyperprolactinemia is an increase in the concentration of the hormone prolactin in the blood. Prolactin along with luteinizing (LH) and follicle-stimulating (FSH) hormones are produced in the endocrine gland of the pituitary gland. The pituitary gland is a kind of “conductor” of the endocrine system. It regulates the activity of various endocrine glands – the thyroid gland, adrenal glands, ovaries and testicles, by producing the corresponding hormones.
Prolactin is sometimes called “milk hormone”, because it stimulates the formation of milk in women after childbirth. In smaller amounts, this hormone is formed in the body of men. Prolactin, along with LH and FSH, regulate sex life and reproduction. In women, they stimulate the formation of female sex hormones – estrogens and egg maturation, and also regulate the menstrual cycle. In men, these hormones stimulate the production of male sex hormone – testosterone, as well as sperm motility.
Causes of Hyperprolactinemia
There are many factors that increase prolactin levels. Physiological and pathological hyperprolactinemia is distinguished. The action of physiological factors is not associated with any disease and is found in healthy women. So, prolactin levels increase during sleep, breastfeeding, stress, increased physical activity, during intercourse, during pregnancy and in the postpartum period. Pathological hyperprolactinemia can be organic and functional.
Organic is caused by pituitary tumors (micro- and macroprolactinomas). This is a benign formation that produces prolactin. Adenomas grow very slowly or do not grow at all. What exactly causes its formation is still not completely clear. Prolactinomas come in various sizes, but the vast majority have a diameter of less than 10 mm and are called microprolactinomas. Much less common are prolactinomas with a size of 10 mm or more, which are called macroprolactinomas. Symptoms of prolactinomas depend on both the patient’s gender and the size of the tumor.
Functional hyperprolactinemia is associated with various diseases: thyroid function insufficiency – hypothyroidism, chronic renal failure, liver cirrhosis, polycystic ovary syndrome, etc. Hyperprolactinemia can occur after operations and injuries in the chest area, frequent curettage of the uterine cavity.
Prolactin levels may increase with certain high-dose medications: antipsychotics, antidepressants, antihypertensives, prostaglandins, estrogens, and oral contraceptives.
It should be noted that quite often elevated prolactin levels are also found in the absence of a visible cause. This is the so-called idiopathic form of hyperprolactinemia. Its reason lies in the increased function of the pituitary cells, the number of which remains normal or increases very slightly.
Symptoms of Hyperprolactinemia
An increase in prolactin levels in the blood can manifest itself in different ways. In women, there is a failure of the second phase of the menstrual cycle, delayed menstruation or their complete absence, violation of ovulation, the excretion of colostrum or milk from the mammary glands (galactorrhea). In connection with the violation of the menstrual cycle, women often develop infertility. In the male body, an excess of prolactin leads to a decrease in the level of testosterone in the blood, as a result of which interest in sex life (libido) is reduced, impotence and infertility develop.
Diagnosis of Hyperprolactinemia
The leading method in the examination of patients with hyperprolactinemia belongs to the hormonal examination – the determination of prolactin in the blood. Blood is taken from a vein in the morning, between the 5th and 8th days of the menstrual cycle. As a rule, with an increased level of the hormone, repeated determinations are required (at least 3). This is due to the possibility of a temporary increase in prolactin levels, which does not indicate the presence of any disease. For the diagnosis of organic hyperprolactinemia, an examination of the pituitary gland using craniography (x-ray of the skull in 2 projections), computed tomography (CT) and magnetic resonance imaging (MRI) is used. The last 2 methods have significantly greater accuracy and informativeness.
The most common drug for treating hyperprolactinemia is bromocriptine (commercial name is parlodel). Other drugs are also used – cabergoline (Dostinex), norprolac. All these drugs help to reduce the release of prolactin by a tumor, the level of which in the blood often drops to normal within a few weeks after the start of treatment. In women, as prolactin normalizes, the menstrual cycle and the ability to conceive are restored. Pregnancy, by the way, can occur quite quickly, therefore, if you are not planning on having a baby at this time, you should discuss with your doctor the most suitable contraception method. In men, along with a decrease in prolactin levels, testosterone levels increase, which normalizes the quality of sexual life. With the use of parlodel, almost all prolactinomas are reduced in size. If you have a very large tumor, you may need to take several tomographic images in dynamics to assess changes in prolactinoma size during treatment.
Due to the effectiveness of drug treatment for prolactinomas, they rarely resort to surgery and radiation therapy. Only a small proportion of patients with macroprolactinomas in whom the size of the tumor does not decrease during the treatment with medication may require surgery or radiation therapy.