00:01
Physiologically, prolactin induces
and regulates lactation.
00:05
Hence, elevated levels of prolactin cause
galactorrhea or abnormal lactation.
00:11
Women are more likely to develop
galactorrhea than men.
00:15
Hyperprolactinemia also causes
hypogonadotropic hypogonadism
because of its negative
feedback effect
on gonadotropin-releasing hormone
in the hypothalamus
which in turn decreases
the levels of LH and FSH.
00:29
Both men and women
can present with hypogonadism.
00:32
Unlike other pituitary tumors,
medication rather than surgery
is first-line therapy
for prolactinomas.
00:39
Even patients with severe mass effects
such as vision loss
are treated with
medical therapy initially.
00:45
Rarely, very large tumors
or more invasive prolactinomas
do not shrink with medical therapy
and continue to grow.
00:53
Surgery should be considered
followed by radiotherapy
if growth occurs
or continues.
01:00
After being debulked, the prolactinoma
may respond better to medical therapy.
01:05
This table reviews
the different causes of hyperprolactinemia.
01:09
Starting with physiologic changes,
the most important one
is pregnancy, and lactation,
as well as nipple stimulation.
01:16
Important medications to consider
include antipsychotic agents,
metoclopramide, cimetidine, verapamil,
methyldopa, opiates, and cocaine.
01:27
Other causes of hyperprolactinemia include
prolactinomas, pituitary tumors,
hypothyroidism, cirrhosis,
and chronic kidney disease.
01:36
Let's take a look at some of these
in more detail.
01:39
The most common cause of elevated levels
of prolactin are obviously pregnancy,
and in the postpartum period,
to facilitate lactation.
01:48
Physiologic stress, coitus,
and exercise can increase
prolactin levels up to
14 nanograms per ml.
01:55
Normal ranges numerical include
two to 29 nanograms per ml in non-pregnant women,
and two to 18 nanograms
per ml in men.
02:06
Nipple piercing can increase prolactin levels
above 200 nanograms per ml.
02:13
Antipsychotic agents cause hyperprolactinemia
due to their antidopaminergic effect
that interrupts the inhibition
of prolactin by dopamine.
02:22
Specific agents such as
risperidone and metoclopramide
may raise the prolactin level
above 200 nanograms per ml.
02:29
Evaluate for pituitary hypersecretion
when a patient is
taking a medication known to raise
the prolactin level.
02:36
When the prolactin level is only mildly elevated,
less than 50 nanograms per ml,
it may be reasonable to assume
that hyperprolactinemia is a medication side effect.
02:46
When significantly elevated,
above 100 nanograms per ml,
either the medication
needs to be withheld
or further assess a pituitary MRI
obtained to evaluate for a prolactinoma.
03:00
Caution is warranted when discontinuation
of an antipsychotic agent is being considered,
and consultation with the psychiatrist
who actually prescribed it
is recommended prior to
acute discontinuation.
03:12
Another cause of hypoprolactinemia
is primary hyperthyroidism.
03:17
Hypothyroidism can cause diffuse swelling
of the pituitary gland
that may resemble enlargement due to a
pituitary adenoma on imaging.
03:26
A patient with primary hypothyroidism
and hyperprolactinemia
should be treated with
thyroid hormone replacement
with the retesting of the prolactin level
once the TSH has normalized.
03:37
Further evaluation is indicated
if the hyperprolactinemia
does not correct
when hyporthyroidism is treated.
03:45
Clinical features and diagnosis
of hyperprolactinemia.
03:48
Symptoms in men are insidious
and may go unrecognized for years.
03:53
Both men and women with hyperprolactinemia
are likely to be infertile
and are at risk for
osteoporosis.
04:01
Postmenopausal women are already hypogonadal
because of ovarian failure.
04:06
Therefore, hyperprolactinemia may have minimal
clinical implications in this group of patients.
04:12
The cause of postmenopausal hyperprolactinemia
still requires diagnosis
because it may be due to a pituitary tumor
that can have effects within the brain.