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| Prolactinoma |
What is a prolactinoma?
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. Symptoms of prolactinoma are
caused by too much prolactin in the blood
(hyperprolactinemia) or by pressure of the tumor on
surrounding tissues.
Prolactin stimulates the breast to produce milk during
pregnancy. After delivery of the baby, a mother's prolactin
levels fall unless she breast feeds her infant. Each time the
baby nurses, prolactin levels rise to maintain milk production.
What is the pituitary gland?
The pituitary gland, sometimes called the master gland, plays
a critical role in regulating growth and development,
metabolism, and reproduction. It produces prolactin and a
variety of other key hormones. These include growth
hormone, which regulates growth; ACTH (corticotropin),
which stimulates the adrenal glands to produce cortisol;
thyrotropin, which signals the thyroid gland to produce
thyroid hormone; and luteinizing hormone and follicle-
stimulating hormone, which regulate ovulation and estrogen
and progesterone production in women, and sperm formation
and testosterone production in men.
The pituitary gland sits in the middle of the head in a bony
box called the sella turcica. The eye nerves sit directly above
the pituitary gland. Enlargement of the gland can cause local
symptoms such as headaches or visual disturbances. Pituitary
tumors may also impair production of one or more pituitary
hormones, causing reduced pituitary function
(hypopituitarism).
How common is prolactinoma?
Autopsy studies indicate that 25 percent of the U.S.
population have small pituitary tumors. Forty percent of these
pituitary tumors produce prolactin, but most are not
considered clinically significant. Clinically significant pituitary
tumors affect the health of approximately 14 out of 100,000
people.
What causes prolactinoma?
Although research continues to unravel the mysteries of
disordered cell growth, the cause of pituitary tumors remains
unknown. Most pituitary tumors are sporadic—they are not
genetically passed from parents to offspring.
What are the symptoms?
In women, high blood levels of prolactin often cause infertility
and changes in menstruation. In some women, periods may
disappear altogether. In others, periods 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). Intercourse
may become painful because of vaginal dryness.
In men, the most common symptom of prolactinoma is
impotence. Because men have no reliable indicator such as
menstruation to signal a problem, many men delay going to
the doctor until they have headaches or eye problems caused
by the enlarged pituitary pressing against nearby eye 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.
What else causes prolactin to rise?
In some people, high blood levels of prolactin can be traced to
causes other than a pituitary tumor.
Prescription Drugs. Prolactin secretion in the pituitary is
normally suppressed by the brain chemical, dopamine. 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 tranquilizers
trifluoperazine (Stelazine) and haloperidol (Haldol);
metoclopramide (Reglan), used to treat gastroesophageal
reflux and the nausea caused by certain cancer drugs; and
less often, alpha methyldopa and reserpine, used to control
hypertension.
Other Pituitary Tumors. Other tumors arising in or near the
pituitary—such as those that cause acromegaly or Cushing's
syndrome—may block the flow of dopamine from the brain to
the prolactin-secreting cells.
Hypothyroidism. Increased prolactin levels are often seen in
people with hypothyroidism, and doctors routinely test people
with hyperprolactinemia for hypothyroidism.
Breast Stimulation also can cause a modest increase in the
amount of prolactin in the blood.
How is prolactinoma diagnosed?
A doctor will test for prolactin blood levels in women with
unexplained milk secretion (galactorrhea) or irregular menses
or infertility, and in men with impaired sexual function and, in
rare cases, 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. The doctor will
also request a magnetic resonance imaging (MRI), which is the
most sensitive test for detecting pituitary tumors and
determining their size. MRI scans may be repeated periodically
to assess tumor progression and the effects of therapy.
Computer 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 tumor,
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 tumor, the
doctor may request an eye exam with measurement of visual
fields.
How is prolactinoma treated?
Medical Treatment
The goal of treatment is to return prolactin secretion to
normal, reduce tumor size, correct any visual abnormalities,
and restore normal pituitary function. In the case of very
large tumors, only partial achievement of this goal may be
possible. Because dopamine is the chemical that normally
inhibits prolactin secretion, doctors may treat prolactinoma
with bromocriptine or cabergoline, drugs that act like
dopamine. This type of drug is called a dopamine agonist.
These drugs shrink the tumor and return prolactin levels to
normal in approximately 80 percent of patients. Both have
been approved by the Food and Drug Administration for the
treatment of hyperprolactinemia. Bromocriptine is the only
dopamine agonist approved for the treatment of infertility.
Another dopamine agonist, pergolide, is available in the U.S.,
but is not approved for treating conditions that cause high
blood levels of prolactin.
Bromocriptine is associated with side effects such as nausea
and dizziness. To avoid these side effects, it is important for
bromocriptine treatment to start slowly. An example of a
typical approach used by an experienced endocrinologist
follows:
Begin by taking a quarter of a 2.5 milligram tablet of
bromocriptine with a snack at bedtime. After 3 days, increase
the dose to a quarter of a tablet with breakfast and a quarter
at bedtime. After 3 more days, take half a tablet twice a day,
and 3 days later, one tablet at night and half with breakfast.
Finally, the dose is increased to one tablet twice a day. If
prolactin is still high, add half a tablet with lunch. If the
medication is well tolerated, increase the dose to a full tablet.
If side effects develop with a higher dose, return to the
previous dosage. With time, side effects disappear while the
drug continues to lower prolactin.
Bromocriptine treatment should not be interrupted without
consulting a qualified endocrinologist. Prolactin levels often
rise again in most people when the drug is discontinued. In
some, however, prolactin levels remain normal, so the doctor
may suggest reducing or discontinuing treatment every two
years on a trial basis.
Cabergoline is also associated with side effects such as
nausea and dizziness, but these may be less common and
less severe than with bromocriptine. As with bromocriptine
therapy, side effects may be avoided if treatment is started
slowly. An example of a typical approach used by an
experienced endocrinologist follows:
Begin by taking .25 milligrams (or 1/2 tablet) twice a week.
After four weeks, increase the dose by .25 milligrams to .50
milligrams (or 1 tablet) twice a week. After four more weeks,
increase the dose by .25 milligrams to .75 milligrams (or 1 1/2
tablets) twice a week. Finally, after four additional weeks, the
dose can be increased to 1 milligram (or 2 tablets) twice a
week. If side effects develop with a higher dose, the doctor
may return to the previous dosage. If a patient's prolactin
level remains normal for 6 months, a doctor may consider
stopping treatment.
Cabergoline should not be interrupted without consulting a
qualified endocrinologist.
Surgery
Surgery should be considered if medical therapy cannot be
tolerated or if it fails to reduce prolactin levels, restore normal
reproduction and pituitary function, and reduce tumor size. If
medical therapy is only partially successful, this therapy
should continue, possibly combined with surgery or radiation.
The results of surgery depend a great deal on tumor size and
prolactin level as well as the skill and experience of the
neurosurgeon. The higher the prolactin level, the lower the
chance of normalizing serum prolactin. In the best medical
centers, surgery corrects prolactin levels in 80 percent of
patients with a serum prolactin less than 250 ng/ml. Even in
patients with large tumors that cannot be completely
removed, drug therapy may be able to return serum prolactin
to the normal range after surgery. Depending on the size of
the tumor and how much of it is removed, studies show that
20 to 50 percent will recur, usually within five years.
How do I choose a skilled neurosurgeon?
Because the results of surgery are so dependent on the skill
and knowledge of the neurosurgeon, a patient should ask the
surgeon about the number of operations he or she has
performed to remove pituitary tumors, and for success and
complication rates in comparison to major medical centers.
The best results come from surgeons who have performed
many hundreds or even thousands of such operations.
How does prolactinoma affect pregnancy and oral
contraceptives?
If a woman has a small prolactinoma, there is no reason that
she cannot conceive and have a normal pregnancy after
successful medical therapy. The pituitary enlarges and
prolactin production increases during normal pregnancy in
women without pituitary disorders. Women with prolactin-
secreting tumors may experience further pituitary
enlargement and must be closely monitored during
pregnancy. However, damage to the pituitary or eye nerves
occurs in less than one percent of pregnant women with
prolactinoma. In women with large tumors, the risk of damage
to the pituitary or eye nerves is greater, and some doctors
consider it as high as 25 percent. If a woman has completed a
successful pregnancy, the chances of her completing further
successful pregnancies is extremely high.
A woman with a prolactinoma should discuss her plans to
conceive with her physician, so she can be carefully evaluated
prior to becoming pregnant. This evaluation will include a
magnetic resonance imaging (MRI) scan to assess the size of
the tumor and an eye examination with measurement of
visual fields. As soon as a patient is pregnant, her doctor will
usually advise that she stop taking bromocriptine or
cabergoline, the common treatments for prolactinoma. Most
endocrinologists see patients every two months throughout
the pregnancy. The patient should consult her endocrinologist
promptly if she develops symptoms—particularly headaches,
visual changes, nausea, vomiting, excessive thirst or
urination, or extreme lethargy. Bromocriptine or cabergoline
treatment may be renewed and additional treatment may be
required if the patient develops symptoms from growth of the
tumor during pregnancy.
At one time, oral contraceptives were thought to contribute
to the development of prolactinomas. However, this is no
longer thought to be true. Patients with prolactinoma treated
with bromocriptine or cabergoline may also take oral
contraceptives. Similarly, post-menopausal estrogen
replacement is safe in patients with prolactinoma treated with
medical therapy or surgery.
Is osteoporosis a risk in women with high prolactin
levels?
Women whose ovaries produce inadequate estrogen are at
increased risk for osteoporosis. Hyperprolactinemia can cause
reduced estrogen production. Although estrogen production
may be restored after treatment for hyperprolactinemia, even
a year or two without estrogen can compromise bone
strength,and these women should protect themselves from
osteoporosis by increasing exercise and calcium intake
through diet or supplementation, and by avoiding smoking.
Women may want to have bone density measurements to
assess the effect of estrogen deficiency on bone density.
They may also want to discuss estrogen replacement therapy
with their physician.
Content Source NIDDK.NIH
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. Symptoms of prolactinoma are
caused by too much prolactin in the blood
(hyperprolactinemia) or by pressure of the tumor on
surrounding tissues.
Prolactin stimulates the breast to produce milk during
pregnancy. After delivery of the baby, a mother's prolactin
levels fall unless she breast feeds her infant. Each time the
baby nurses, prolactin levels rise to maintain milk production.
What is the pituitary gland?
The pituitary gland, sometimes called the master gland, plays
a critical role in regulating growth and development,
metabolism, and reproduction. It produces prolactin and a
variety of other key hormones. These include growth
hormone, which regulates growth; ACTH (corticotropin),
which stimulates the adrenal glands to produce cortisol;
thyrotropin, which signals the thyroid gland to produce
thyroid hormone; and luteinizing hormone and follicle-
stimulating hormone, which regulate ovulation and estrogen
and progesterone production in women, and sperm formation
and testosterone production in men.
The pituitary gland sits in the middle of the head in a bony
box called the sella turcica. The eye nerves sit directly above
the pituitary gland. Enlargement of the gland can cause local
symptoms such as headaches or visual disturbances. Pituitary
tumors may also impair production of one or more pituitary
hormones, causing reduced pituitary function
(hypopituitarism).
How common is prolactinoma?
Autopsy studies indicate that 25 percent of the U.S.
population have small pituitary tumors. Forty percent of these
pituitary tumors produce prolactin, but most are not
considered clinically significant. Clinically significant pituitary
tumors affect the health of approximately 14 out of 100,000
people.
What causes prolactinoma?
Although research continues to unravel the mysteries of
disordered cell growth, the cause of pituitary tumors remains
unknown. Most pituitary tumors are sporadic—they are not
genetically passed from parents to offspring.
What are the symptoms?
In women, high blood levels of prolactin often cause infertility
and changes in menstruation. In some women, periods may
disappear altogether. In others, periods 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). Intercourse
may become painful because of vaginal dryness.
In men, the most common symptom of prolactinoma is
impotence. Because men have no reliable indicator such as
menstruation to signal a problem, many men delay going to
the doctor until they have headaches or eye problems caused
by the enlarged pituitary pressing against nearby eye 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.
What else causes prolactin to rise?
In some people, high blood levels of prolactin can be traced to
causes other than a pituitary tumor.
Prescription Drugs. Prolactin secretion in the pituitary is
normally suppressed by the brain chemical, dopamine. 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 tranquilizers
trifluoperazine (Stelazine) and haloperidol (Haldol);
metoclopramide (Reglan), used to treat gastroesophageal
reflux and the nausea caused by certain cancer drugs; and
less often, alpha methyldopa and reserpine, used to control
hypertension.
Other Pituitary Tumors. Other tumors arising in or near the
pituitary—such as those that cause acromegaly or Cushing's
syndrome—may block the flow of dopamine from the brain to
the prolactin-secreting cells.
Hypothyroidism. Increased prolactin levels are often seen in
people with hypothyroidism, and doctors routinely test people
with hyperprolactinemia for hypothyroidism.
Breast Stimulation also can cause a modest increase in the
amount of prolactin in the blood.
How is prolactinoma diagnosed?
A doctor will test for prolactin blood levels in women with
unexplained milk secretion (galactorrhea) or irregular menses
or infertility, and in men with impaired sexual function and, in
rare cases, 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. The doctor will
also request a magnetic resonance imaging (MRI), which is the
most sensitive test for detecting pituitary tumors and
determining their size. MRI scans may be repeated periodically
to assess tumor progression and the effects of therapy.
Computer 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 tumor,
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 tumor, the
doctor may request an eye exam with measurement of visual
fields.
How is prolactinoma treated?
Medical Treatment
The goal of treatment is to return prolactin secretion to
normal, reduce tumor size, correct any visual abnormalities,
and restore normal pituitary function. In the case of very
large tumors, only partial achievement of this goal may be
possible. Because dopamine is the chemical that normally
inhibits prolactin secretion, doctors may treat prolactinoma
with bromocriptine or cabergoline, drugs that act like
dopamine. This type of drug is called a dopamine agonist.
These drugs shrink the tumor and return prolactin levels to
normal in approximately 80 percent of patients. Both have
been approved by the Food and Drug Administration for the
treatment of hyperprolactinemia. Bromocriptine is the only
dopamine agonist approved for the treatment of infertility.
Another dopamine agonist, pergolide, is available in the U.S.,
but is not approved for treating conditions that cause high
blood levels of prolactin.
Bromocriptine is associated with side effects such as nausea
and dizziness. To avoid these side effects, it is important for
bromocriptine treatment to start slowly. An example of a
typical approach used by an experienced endocrinologist
follows:
Begin by taking a quarter of a 2.5 milligram tablet of
bromocriptine with a snack at bedtime. After 3 days, increase
the dose to a quarter of a tablet with breakfast and a quarter
at bedtime. After 3 more days, take half a tablet twice a day,
and 3 days later, one tablet at night and half with breakfast.
Finally, the dose is increased to one tablet twice a day. If
prolactin is still high, add half a tablet with lunch. If the
medication is well tolerated, increase the dose to a full tablet.
If side effects develop with a higher dose, return to the
previous dosage. With time, side effects disappear while the
drug continues to lower prolactin.
Bromocriptine treatment should not be interrupted without
consulting a qualified endocrinologist. Prolactin levels often
rise again in most people when the drug is discontinued. In
some, however, prolactin levels remain normal, so the doctor
may suggest reducing or discontinuing treatment every two
years on a trial basis.
Cabergoline is also associated with side effects such as
nausea and dizziness, but these may be less common and
less severe than with bromocriptine. As with bromocriptine
therapy, side effects may be avoided if treatment is started
slowly. An example of a typical approach used by an
experienced endocrinologist follows:
Begin by taking .25 milligrams (or 1/2 tablet) twice a week.
After four weeks, increase the dose by .25 milligrams to .50
milligrams (or 1 tablet) twice a week. After four more weeks,
increase the dose by .25 milligrams to .75 milligrams (or 1 1/2
tablets) twice a week. Finally, after four additional weeks, the
dose can be increased to 1 milligram (or 2 tablets) twice a
week. If side effects develop with a higher dose, the doctor
may return to the previous dosage. If a patient's prolactin
level remains normal for 6 months, a doctor may consider
stopping treatment.
Cabergoline should not be interrupted without consulting a
qualified endocrinologist.
Surgery
Surgery should be considered if medical therapy cannot be
tolerated or if it fails to reduce prolactin levels, restore normal
reproduction and pituitary function, and reduce tumor size. If
medical therapy is only partially successful, this therapy
should continue, possibly combined with surgery or radiation.
The results of surgery depend a great deal on tumor size and
prolactin level as well as the skill and experience of the
neurosurgeon. The higher the prolactin level, the lower the
chance of normalizing serum prolactin. In the best medical
centers, surgery corrects prolactin levels in 80 percent of
patients with a serum prolactin less than 250 ng/ml. Even in
patients with large tumors that cannot be completely
removed, drug therapy may be able to return serum prolactin
to the normal range after surgery. Depending on the size of
the tumor and how much of it is removed, studies show that
20 to 50 percent will recur, usually within five years.
How do I choose a skilled neurosurgeon?
Because the results of surgery are so dependent on the skill
and knowledge of the neurosurgeon, a patient should ask the
surgeon about the number of operations he or she has
performed to remove pituitary tumors, and for success and
complication rates in comparison to major medical centers.
The best results come from surgeons who have performed
many hundreds or even thousands of such operations.
How does prolactinoma affect pregnancy and oral
contraceptives?
If a woman has a small prolactinoma, there is no reason that
she cannot conceive and have a normal pregnancy after
successful medical therapy. The pituitary enlarges and
prolactin production increases during normal pregnancy in
women without pituitary disorders. Women with prolactin-
secreting tumors may experience further pituitary
enlargement and must be closely monitored during
pregnancy. However, damage to the pituitary or eye nerves
occurs in less than one percent of pregnant women with
prolactinoma. In women with large tumors, the risk of damage
to the pituitary or eye nerves is greater, and some doctors
consider it as high as 25 percent. If a woman has completed a
successful pregnancy, the chances of her completing further
successful pregnancies is extremely high.
A woman with a prolactinoma should discuss her plans to
conceive with her physician, so she can be carefully evaluated
prior to becoming pregnant. This evaluation will include a
magnetic resonance imaging (MRI) scan to assess the size of
the tumor and an eye examination with measurement of
visual fields. As soon as a patient is pregnant, her doctor will
usually advise that she stop taking bromocriptine or
cabergoline, the common treatments for prolactinoma. Most
endocrinologists see patients every two months throughout
the pregnancy. The patient should consult her endocrinologist
promptly if she develops symptoms—particularly headaches,
visual changes, nausea, vomiting, excessive thirst or
urination, or extreme lethargy. Bromocriptine or cabergoline
treatment may be renewed and additional treatment may be
required if the patient develops symptoms from growth of the
tumor during pregnancy.
At one time, oral contraceptives were thought to contribute
to the development of prolactinomas. However, this is no
longer thought to be true. Patients with prolactinoma treated
with bromocriptine or cabergoline may also take oral
contraceptives. Similarly, post-menopausal estrogen
replacement is safe in patients with prolactinoma treated with
medical therapy or surgery.
Is osteoporosis a risk in women with high prolactin
levels?
Women whose ovaries produce inadequate estrogen are at
increased risk for osteoporosis. Hyperprolactinemia can cause
reduced estrogen production. Although estrogen production
may be restored after treatment for hyperprolactinemia, even
a year or two without estrogen can compromise bone
strength,and these women should protect themselves from
osteoporosis by increasing exercise and calcium intake
through diet or supplementation, and by avoiding smoking.
Women may want to have bone density measurements to
assess the effect of estrogen deficiency on bone density.
They may also want to discuss estrogen replacement therapy
with their physician.
Content Source NIDDK.NIH
| MEDICAL NOTES |
DISEASES AND
CONDITIONS
Acidosis
Acne
Acromegaly
Addison's Disease
Adrenal Crisis
Age. macular degn
Alzheimer's disease
Autoimmune
Hepatitis
Barrett's Esophagus
Cancer
Constipation
Colon Polyps
Crohns Disease
Cushing's Syndrm.
Diabetes
Erectile Dysfunction
Fecal Incontinence
Gallstones
Gastritis
Gastroenteritis
Gastroesophageal
Reflux (GERD)
Growth Hormone
Def.
Heartburn
Hemochromatosis
Hemorrhoids
Hyperparathyroidism
Hypertension
Inflam. Bowel Dis.
Kidney Stone
Liver Cirrhosis
Migraines
Multiple Sclerosis
Obesity
Osteorithritis
Osteoporosis
Pancreatitis
Parkinson's Disease
Peyronies' Disease
Prolactinoma
Psoriasis
Sprain and Strain
Stroke
Ulcerative Colitis
Urin. Incontinence
Vitiligo
CONDITIONS
Acidosis
Acne
Acromegaly
Addison's Disease
Adrenal Crisis
Age. macular degn
Alzheimer's disease
Autoimmune
Hepatitis
Barrett's Esophagus
Cancer
Constipation
Colon Polyps
Crohns Disease
Cushing's Syndrm.
Diabetes
Erectile Dysfunction
Fecal Incontinence
Gallstones
Gastritis
Gastroenteritis
Gastroesophageal
Reflux (GERD)
Growth Hormone
Def.
Heartburn
Hemochromatosis
Hemorrhoids
Hyperparathyroidism
Hypertension
Inflam. Bowel Dis.
Kidney Stone
Liver Cirrhosis
Migraines
Multiple Sclerosis
Obesity
Osteorithritis
Osteoporosis
Pancreatitis
Parkinson's Disease
Peyronies' Disease
Prolactinoma
Psoriasis
Sprain and Strain
Stroke
Ulcerative Colitis
Urin. Incontinence
Vitiligo