Hyperprolactinaemia
Encyclopedia
Hyperprolactinaemia or hyperprolactinemia (HP) is the presence of abnormally-high levels of prolactin
in the blood. Normal levels
are less than 500 mIU/L for women, and less than 450 mIU/L for men.
Prolactin is a peptide hormone
produced by the anterior pituitary gland
primarily associated with lactation
and plays a vital role in breast development during pregnancy
. Hyperprolactinaemia may cause production and spontaneous flow of breast milk and disruptions in the normal menstrual period in women and hypogonadism
, infertility
and erectile dysfunction
in men.
Hyperprolactinaemia can be a part of normal body changes during pregnancy and breastfeeding. It can also be caused by diseases affecting the hypothalamus
and pituitary gland. It can also be caused by disruption of the normal regulation of prolactin levels by drugs, medicinal herbs and heavy metals. Hyperprolactinaemia may also be the result of disease of other organs such as the liver, kidneys, ovaries and thyroid.
(a pituitary gland adenoma
tumour). A blood serum prolactin level of 1000–5000 mIU/L could be from either mechanism, but >5000 mIU/L is likely due to the activity of an adenoma with macroadenomas (large tumours over 10 mm diameter) whose levels of prolactin are up to 100,000 mIU/L. Hyperprolactinaemia inhibits gonadotropin-releasing hormone
(GnRH) by increasing the release of dopamine
from the arcuate nucleus
of the hypothalamus
(dopamine inhibits GnRH secretion), thus inhibiting gonadal steroidogenesis, which is the cause of many of the symptoms described below.
There is a suspicion that Minoxidil
, a potassium channel
agonist, may be related to the development of this disease. A two-year test with Minoxidil, under normal dosing parameters, was carried out on rats, which caused phaeochromocytoma
s in both males and females, and preputial gland
adenomas in males.
, breastfeeding
, mental stress
, sleep, hypothyroidism
.
. Drugs that block the effects of dopamine at the pituitary or deplete dopamine stores in the brain may cause the pituitary to secrete prolactin. These drugs include the major tranquillizers
(phenothiazine
s), trifluoperazine
(Stelazine), and haloperidol
(Haldol); antipsychotic
medications in general; metoclopramide
(Reglan), domperidone
, cisapride
used to treat gastro-oesophageal reflux
and medication induced nausea(such as cancer drugs); and, less often, alpha-methyldopa
and reserpine
, used to control hypertension
; and oestrogens
and TRH
. The sleep drug ramelteon
(Rozerem) also increases the risk of hyperprolactinaemia. In particular, the dopamine antagonists metoclopramide and domperidone are both powerful prolactin stimulators and have been used to stimulate breastmilk secretion for decades. However since prolactin is antagonized by dopamine and the body depends on the two being in balance, the risk of prolactin stimulation is generally present with all drugs that deplete dopamine, either directly or as a rebound effect.
Risperidone can also cause hyperprolactinaemia
or Cushing's disease
— may block the flow of dopamine from the brain to the prolactin-secreting cells, likewise, division of the pituitary stalk
or hypothalamic disease. Other causes include chronic renal failure
, hypothyroidism
, bronchogenic carcinoma and sarcoidosis
. Some women with polycystic ovary syndrome
may have mildly-elevated prolactin levels.
Apart from diagnosing hyperprolactinaemia and hypopituitarism
, prolactin levels are often determined by physicians in patients that have suffered a seizure
, when there is doubt as to whether this was an epileptic seizure or a non-epileptic seizure. Shortly after epileptic seizures, prolactin levels often rise, whereas they are normal in non-epileptic seizures.
with anovulatory infertility
and a decrease in menstruation
. In some women, menstruation may disappear altogether (amenorrhoea
). In others, menstruation may become irregular or menstrual flow may change. Women who are not pregnant or nursing may begin producing breast milk
. Some women may experience a loss of libido
(interest in sex) and breast pain, especially when prolactin levels begin to rise for the first time, as the hormone promotes tissue changes in the breast. Intercourse
may become painful because of vaginal dryness.
In men, the most common symptoms of hyperprolactinaemia are decreased libido
, erectile dysfunction
, infertility
and gynaecomastia
. Because men have no reliable indicator such as menstruation
to signal a problem, many men with hyperprolactinaemia being caused by an adenoma may delay going to the doctor until they have headaches or eye problems caused by the enlarged pituitary pressing against nearby optic nerves. They may not recognize a gradual loss of sexual function or libido
. Only after treatment do some men realize they had a problem with sexual function.
Because of hypoestrogenism and hypogonadism (low testosterone), hyperprolactinaemia can lead to osteoporosis
.
) or irregular menses or infertility
, and in men with impaired sexual function and milk secretion. If prolactin is high, a doctor will test thyroid
function and ask first about other conditions and medications known to raise prolactin secretion. While a plain X-ray
of the bones surrounding the pituitary may reveal the presence of a large macro-adenoma, the small micro-adenoma will not be apparent. Magnetic resonance imaging (MRI) is the most sensitive test for detecting pituitary tumours and determining their size. MRI scans may be repeated periodically to assess tumour progression and the effects of therapy. Computed Tomography
(CT scan) also gives an image of the pituitary, but it is less sensitive than the MRI.
In addition to assessing the size of the pituitary tumour, doctors also look for damage to surrounding tissues, and perform tests to assess whether production of other pituitary hormones is normal. Depending on the size of the tumour, the doctor may request an eye exam with measurement of visual fields.
The hormone prolactin is downregulated by dopamine
and is upregulated by oestrogen
. A falsely-high measurement may occur due to the presence of the biologically-inactive macroprolactin
in the serum. This can show up as high prolactin in some types of tests, but is asymptomatic.
s such as cabergoline
, bromocriptine
(often preferred when pregnancy is possible), and less frequently lisuride
. A new drug in use is norprolac with the active ingredient quinagolide
.
Vitex agnus-castus
extract can be tried in cases of mild hyperprolactinaemia.
Prolactin
Prolactin also known as luteotropic hormone is a protein that in humans is encoded by the PRL gene.Prolactin is a peptide hormone discovered by Henry Friesen...
in the blood. Normal levels
Reference ranges for common blood tests
Reference ranges for blood tests are sets of values used by a health professional to interpret a set of medical test results from blood samples....
are less than 500 mIU/L for women, and less than 450 mIU/L for men.
Prolactin is a peptide hormone
Peptide hormone
Peptide hormones are a class of peptides that are secreted into the blood stream and have endocrine functions in living animals.Like other proteins, peptide hormones are synthesized in cells from amino acids according to an mRNA template, which is itself synthesized from a DNA template inside the...
produced by the anterior pituitary gland
Pituitary gland
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...
primarily associated with lactation
Lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process occurs in all female mammals, however it predates mammals. In humans the process of feeding milk is called breastfeeding or nursing...
and plays a vital role in breast development during pregnancy
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
. Hyperprolactinaemia may cause production and spontaneous flow of breast milk and disruptions in the normal menstrual period in women and hypogonadism
Hypogonadism
Hypogonadism is a medical term for decreased functional activity of the gonads. Low testosterone is caused by a decline or deficiency in gonadal production of testosterone in males...
, infertility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
and erectile dysfunction
Erectile dysfunction
Erectile dysfunction is sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual performance....
in men.
Hyperprolactinaemia can be a part of normal body changes during pregnancy and breastfeeding. It can also be caused by diseases affecting the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
and pituitary gland. It can also be caused by disruption of the normal regulation of prolactin levels by drugs, medicinal herbs and heavy metals. Hyperprolactinaemia may also be the result of disease of other organs such as the liver, kidneys, ovaries and thyroid.
Causes
Hyperprolactinaemia may be caused by either disinhibition (e.g., compression of the pituitary stalk or reduced dopamine levels) or excess production from a prolactinomaProlactinoma
A prolactinoma is a benign tumor of the pituitary gland that produces a hormone called prolactin. It is the most common type of pituitary tumor...
(a pituitary gland adenoma
Adenoma
An adenoma is a benign tumor of glandular origin. Adenomas can grow from many organs including the colon, adrenal glands, pituitary gland, thyroid, prostate, etc. Although these growths are benign, over time they may progress to become malignant, at which point they are called adenocarcinomas...
tumour). A blood serum prolactin level of 1000–5000 mIU/L could be from either mechanism, but >5000 mIU/L is likely due to the activity of an adenoma with macroadenomas (large tumours over 10 mm diameter) whose levels of prolactin are up to 100,000 mIU/L. Hyperprolactinaemia inhibits gonadotropin-releasing hormone
Gonadotropin-releasing hormone
Gonadotropin-releasing hormone , also known as Luteinizing-hormone-releasing hormone and luliberin, is a tropic peptide hormone responsible for the release of follicle-stimulating hormone and luteinizing hormone from the anterior pituitary. GnRH is synthesized and released from neurons within...
(GnRH) by increasing the release of dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
from the arcuate nucleus
Arcuate nucleus
The arcuate nucleus is an aggregation of neurons in the mediobasal hypothalamus, adjacent to the third ventricle and the median eminence...
of the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
(dopamine inhibits GnRH secretion), thus inhibiting gonadal steroidogenesis, which is the cause of many of the symptoms described below.
There is a suspicion that Minoxidil
Minoxidil
Minoxidil is an antihypertensive vasodilator medication which also slows or stops hair loss and promotes hair regrowth. Now off-patent, it is available over-the-counter for the treatment of androgenic alopecia. Minoxidil must be used indefinitely for continued support of existing hair follicles and...
, a potassium channel
Potassium channel
In the field of cell biology, potassium channels are the most widely distributed type of ion channel and are found in virtually all living organisms. They form potassium-selective pores that span cell membranes...
agonist, may be related to the development of this disease. A two-year test with Minoxidil, under normal dosing parameters, was carried out on rats, which caused phaeochromocytoma
Pheochromocytoma
A pheochromocytoma or phaeochromocytoma is a neuroendocrine tumor of the medulla of the adrenal glands , or extra-adrenal chromaffin tissue that failed to involute after birth and secretes excessive amounts of catecholamines, usually noradrenaline , and adrenaline to a lesser extent...
s in both males and females, and preputial gland
Preputial gland
Preputial glands are exocrine glands that are located in front of the genitals of some mammals and produce pheromones. The preputial glands of female animals are sometimes called clitoral glands....
adenomas in males.
Physiological causes
Physiological causes (i.e., as result of normal body functioning): pregnancyPregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
, breastfeeding
Breastfeeding
Breastfeeding is the feeding of an infant or young child with breast milk directly from female human breasts rather than from a baby bottle or other container. Babies have a sucking reflex that enables them to suck and swallow milk. It is recommended that mothers breastfeed for six months or...
, mental stress
Stress (medicine)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
, sleep, hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
.
Prescription drugs
Use of prescription drugs is the most common cause of hyperprolactinaemia. Prolactin secretion in the pituitary is normally suppressed by the brain chemical dopamineDopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
. Drugs that block the effects of dopamine at the pituitary or deplete dopamine stores in the brain may cause the pituitary to secrete prolactin. These drugs include the major tranquillizers
Sedative
A sedative or tranquilizer is a substance that induces sedation by reducing irritability or excitement....
(phenothiazine
Phenothiazine
Phenothiazine is an organic compound that occurs in various antipsychotic and antihistaminic drugs. It has the formula S2NH. This yellow tricyclic compound is soluble in acetic acid, benzene, and ether. The compound is related to the thiazine-class of heterocyclic compounds...
s), trifluoperazine
Trifluoperazine
Trifluoperazine is a typical antipsychotic of the phenothiazine chemical class.- Uses :...
(Stelazine), and haloperidol
Haloperidol
Haloperidol is a typical antipsychotic. It is in the butyrophenone class of antipsychotic medications and has pharmacological effects similar to the phenothiazines....
(Haldol); antipsychotic
Antipsychotic
An antipsychotic is a tranquilizing psychiatric medication primarily used to manage psychosis , particularly in schizophrenia and bipolar disorder. A first generation of antipsychotics, known as typical antipsychotics, was discovered in the 1950s...
medications in general; metoclopramide
Metoclopramide
Metoclopramide is an antiemetic and gastroprokinetic agent. It is commonly used to treat nausea and vomiting, to facilitate gastric emptying in people with gastroparesis, and as a treatment for the gastric stasis often associated with migraine headaches.-Medical uses:Metoclopramide is commonly...
(Reglan), domperidone
Domperidone
Domperidone is an antidopaminergic drug, developed by Janssen Pharmaceutica, and used orally, rectally or intravenously, generally to suppress nausea and vomiting, or as a prokinetic agent...
, cisapride
Cisapride
Cisapride is a gastroprokinetic agent, a drug which increases motility in the upper gastrointestinal tract. It acts directly as a serotonin 5-HT4 receptor agonist and indirectly as a parasympathomimetic. Stimulation of the serotonin receptors increases acetylcholine release in the enteric nervous...
used to treat gastro-oesophageal reflux
Gastroesophageal reflux disease
Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...
and medication induced nausea(such as cancer drugs); and, less often, alpha-methyldopa
Methyldopa
Methyldopa is an alpha-adrenergic agonist psychoactive drug used as a sympatholytic or antihypertensive. Its use is now mostly deprecated following the introduction of alternative safer classes of agents...
and reserpine
Reserpine
Reserpine is an indole alkaloid antipsychotic and antihypertensive drug that has been used for the control of high blood pressure and for the relief of psychotic symptoms, although because of the development of better drugs for these purposes and because of its numerous side-effects, it is rarely...
, used to control hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
; and oestrogens
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
and TRH
Thyrotropin-releasing hormone
Thyrotropin-releasing hormone , also called thyrotropin-releasing factor , thyroliberin or protirelin, is a tropic tripeptide hormone that stimulates the release of thyroid-stimulating hormone and prolactin by the anterior pituitary...
. The sleep drug ramelteon
Ramelteon
Ramelteon, marketed as Rozerem by Takeda Pharmaceuticals North America, is the first in a new class of sleep agents that selectively binds to the MT1 and MT2 receptors in the suprachiasmatic nucleus , instead of binding to GABA A receptors, such as with drugs like zolpidem, eszopiclone, and...
(Rozerem) also increases the risk of hyperprolactinaemia. In particular, the dopamine antagonists metoclopramide and domperidone are both powerful prolactin stimulators and have been used to stimulate breastmilk secretion for decades. However since prolactin is antagonized by dopamine and the body depends on the two being in balance, the risk of prolactin stimulation is generally present with all drugs that deplete dopamine, either directly or as a rebound effect.
Risperidone can also cause hyperprolactinaemia
Diseases
Prolactinoma or other tumours arising in or near the pituitary — such as those that cause acromegalyAcromegaly
Acromegaly is a syndrome that results when the anterior pituitary gland produces excess growth hormone after epiphyseal plate closure at puberty...
or Cushing's disease
Cushing's disease
Cushing's disease is a cause of Cushing's Syndrome characterised by increased secretion of adrenocorticotropic hormone from the anterior pituitary. This is most often as a result of a pituitary adenoma...
— may block the flow of dopamine from the brain to the prolactin-secreting cells, likewise, division of the pituitary stalk
Pituitary stalk
The pituitary stalk is the connection between the hypothalamus and the posterior pituitary....
or hypothalamic disease. Other causes include chronic renal failure
Chronic renal failure
Chronic kidney disease , also known as chronic renal disease, is a progressive loss in renal function over a period of months or years. The symptoms of worsening kidney function are unspecific, and might include feeling generally unwell and experiencing a reduced appetite...
, hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
, bronchogenic carcinoma and sarcoidosis
Sarcoidosis
Sarcoidosis , also called sarcoid, Besnier-Boeck disease or Besnier-Boeck-Schaumann disease, is a disease in which abnormal collections of chronic inflammatory cells form as nodules in multiple organs. The cause of sarcoidosis is unknown...
. Some women with polycystic ovary syndrome
Polycystic ovary syndrome
Polycystic ovary syndrome is one of the most common female endocrine disorders. PCOS is a complex, heterogeneous disorder of uncertain aetiology, but there is strong evidence that it can to a large degree be classified as a genetic disease....
may have mildly-elevated prolactin levels.
Apart from diagnosing hyperprolactinaemia and hypopituitarism
Hypopituitarism
Hypopituitarism is the decreased secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain...
, prolactin levels are often determined by physicians in patients that have suffered a seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
, when there is doubt as to whether this was an epileptic seizure or a non-epileptic seizure. Shortly after epileptic seizures, prolactin levels often rise, whereas they are normal in non-epileptic seizures.
Idiopathic
In many patients, elevated levels remain unexplained and may represent a form of hypothalamic-pituitary dysregulation.Symptoms
In women, a high blood level of prolactin often causes hypo-oestrogenismHypoestrogenism
Hypoestrogenism refers to a lower than normal level of estrogen, the primary sex hormone for women. In general, lower levels of estrogen may cause differences in the breasts, genitals, urinary tract and skin....
with anovulatory infertility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
and a decrease in menstruation
Menstruation
Menstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
. In some women, menstruation may disappear altogether (amenorrhoea
Amenorrhoea
Amenorrhoea , amenorrhea , or amenorrhœa, is the absence of a menstrual period in a woman of reproductive age. Physiological states of amenorrhoea are seen during pregnancy and lactation , the latter also forming the basis of a form of contraception known as the lactational amenorrhoea method...
). In others, menstruation may become irregular or menstrual flow may change. Women who are not pregnant or nursing may begin producing breast milk
Breast milk
Breast milk, more specifically human milk, is the milk produced by the breasts of a human female for her infant offspring...
. Some women may experience a loss of libido
Libido
Libido refers to a person's sex drive or desire for sexual activity. The desire for sex is an aspect of a person's sexuality, but varies enormously from one person to another, and it also varies depending on circumstances at a particular time. A person who has extremely frequent or a suddenly...
(interest in sex) and breast pain, especially when prolactin levels begin to rise for the first time, as the hormone promotes tissue changes in the breast. Intercourse
Sexual intercourse
Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which a male's penis enters a female's vagina for the purposes of sexual pleasure or reproduction. The entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails...
may become painful because of vaginal dryness.
In men, the most common symptoms of hyperprolactinaemia are decreased libido
Libido
Libido refers to a person's sex drive or desire for sexual activity. The desire for sex is an aspect of a person's sexuality, but varies enormously from one person to another, and it also varies depending on circumstances at a particular time. A person who has extremely frequent or a suddenly...
, erectile dysfunction
Erectile dysfunction
Erectile dysfunction is sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual performance....
, infertility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
and gynaecomastia
Gynecomastia
Gynecomastia or Gynaecomastia, , is the abnormal development of large mammary glands in males resulting in breast enlargement. The term comes from the Greek γυνή gyné meaning "woman" and μαστός mastós meaning "breast"...
. Because men have no reliable indicator such as menstruation
Menstruation
Menstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
to signal a problem, many men with hyperprolactinaemia being caused by an adenoma may delay going to the doctor until they have headaches or eye problems caused by the enlarged pituitary pressing against nearby optic nerves. They may not recognize a gradual loss of sexual function or libido
Libido
Libido refers to a person's sex drive or desire for sexual activity. The desire for sex is an aspect of a person's sexuality, but varies enormously from one person to another, and it also varies depending on circumstances at a particular time. A person who has extremely frequent or a suddenly...
. Only after treatment do some men realize they had a problem with sexual function.
Because of hypoestrogenism and hypogonadism (low testosterone), hyperprolactinaemia can lead to osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
.
Diagnosis
A doctor will test for prolactin blood levels in women with unexplained milk secretion (galactorrhoeaGalactorrhea
Galactorrhea or galactorrhoea is the spontaneous flow of milk from the breast, unassociated with childbirth or nursing.Contemporary Maternal-Newborn Nursing Care defines galactorrhea as "nipple discharge." -Causes:...
) or irregular menses or infertility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
, and in men with impaired sexual function and milk secretion. If prolactin is high, a doctor will test thyroid
Thyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...
function and ask first about other conditions and medications known to raise prolactin secretion. While a plain X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
of the bones surrounding the pituitary may reveal the presence of a large macro-adenoma, the small micro-adenoma will not be apparent. Magnetic resonance imaging (MRI) is the most sensitive test for detecting pituitary tumours and determining their size. MRI scans may be repeated periodically to assess tumour progression and the effects of therapy. Computed Tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
(CT scan) also gives an image of the pituitary, but it is less sensitive than the MRI.
In addition to assessing the size of the pituitary tumour, doctors also look for damage to surrounding tissues, and perform tests to assess whether production of other pituitary hormones is normal. Depending on the size of the tumour, the doctor may request an eye exam with measurement of visual fields.
The hormone prolactin is downregulated by dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
and is upregulated by oestrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
. A falsely-high measurement may occur due to the presence of the biologically-inactive macroprolactin
Macroprolactin
Macroprolactin is a physiologically inactive form of prolactin found in a small proportion of people. It is in fact prolactin bound to IgG.Macroprolactin is important, as some laboratory assays will detect it as prolactin, leading to a falsely elevated prolactin result...
in the serum. This can show up as high prolactin in some types of tests, but is asymptomatic.
Treatment
Treatment is usually medication with dopamine agonistDopamine agonist
A dopamine agonist is a compound that activates dopamine receptors in the absence of dopamine. Dopamine agonists activate signaling pathways through the dopamine receptor and trimeric G-proteins, ultimately leading to changes in gene transcription.-Uses:...
s such as cabergoline
Cabergoline
Cabergoline , an ergot derivative, is a potent dopamine receptor agonist on D2 receptors. In vitro, rat studies show cabergoline has a direct inhibitory effect on pituitary lactotroph cells...
, bromocriptine
Bromocriptine
Bromocriptine , an ergoline derivative, is a dopamine agonist that is used in the treatment of pituitary tumors, Parkinson's disease , hyperprolactinaemia, neuroleptic malignant syndrome, and type 2 diabetes.- Indications :Amenorrhea, female infertility, galactorrhea, hypogonadism, and acromegaly...
(often preferred when pregnancy is possible), and less frequently lisuride
Lisuride
Lisuride is an antiparkinson agent of the iso-ergoline class, chemically related to the dopaminergic ergoline Parkinson's drugs. Lisuride is described as free base and as hydrogen maleate salt.Lisuride is used to lower prolactin and, in low doses, to prevent migraine attacks...
. A new drug in use is norprolac with the active ingredient quinagolide
Quinagolide
Quinagolide is a selective, D2 receptor agonist that is used for the treatment of elevated levels of prolactin....
.
Vitex agnus-castus
Vitex agnus-castus
Vitex agnus-castus, also called Vitex, Chaste Tree, Chasteberry, Abraham's Balm or Monk's Pepper, is a native of the Mediterranean region. It is one of the few temperate-zone species of Vitex, which is on the whole a genus of tropical and sub-tropical flowering plants...
extract can be tried in cases of mild hyperprolactinaemia.
Historical eponyms
The following eponyms were established before prolactin levels could be measured reliably in the clinical setting. On occasion, they are still encountered:- Ahumada-DelCastilloHospital de Clínicas "José de San Martín"The Hospital de Clínicas "José de San Martín" is a teaching hospital located in Buenos Aires, Argentina. It belongs to the University of Buenos Aires , currently the best ranked university in that country.-History:...
Syndrome, which refers to the association of galactorrhoea and amenorrhoea. - ChiariHans ChiariHans Chiari was an Austrian pathologist who was a native of Vienna. He was the son of gynecologist Johann Baptist Chiari , and brother to rhinolaryngologist Ottokar Chiari ....
-Frommel Syndrome, which refers to extended postpartum galactorrhoea and amenorrhoea. - Forbes-Albright Syndrome, which refers to galactorrhoea-amenorrhoea associated with a pituitary tumour.