00:00
Hello. I would like to discuss primary and secondary amenorrhea with you. This is often tested
on the USMLE so pay close attention. Let's review what a normal menstrual cycle is like. It's
between 21 and 35 days. There is another lecture about AUB if you'd like to find out more. I'd
like to discuss the terminology that we use. Oligomenorrhea means periods that are greater
than every 35 days apart. It can also mean less than 9 menstrual cycles per year. Polymenorrhea
is different. It actually means that your periods come too frequently. They are less than 21
days in the intermenstrual bleeding. Menorrhagia means you have too much flow greater than
80 mL in 7 days. Metrorrhagia means that you have a regular bleeding between menses. Amenorrhea
means no menses, that can be either primary or secondary and we'll find out more in just a second.
01:07
Dysmenorrhea is defined as painful periods.
01:11
There are two types of dysmenorrhea
with primary dysmenorrhea,
and you have painful menstruation
in the absence of any pelvic pathology.
01:20
Primary dysmenorrhea
characteristically begins when adolescents
attain ambulatory cycles, meaning
they start to actually ovulate
because you don't always ovulate
at the beginning of menarche.
01:31
Usually this occurs
within six to 12 months of menarche.
01:36
Secondary dysentery
refers to painful menses
due to pelvic pathology
or a recognized medical condition.
01:45
Such as endometriosis,
which is the most common cause.
01:48
Let's talk now about AUB classification.
01:52
This is a newer classification,
and it starts
with AUB, AUB/HMB which is heavy
menstrual bleeding,
which was formerly referred to as menorrhagia.
02:02
Intermenstrual Bleeding, which was
formerly referred to as metrorrhagia.
02:08
Remember, if you'd like to know the new terminology please refer to the AUB lecture. So this is
an overview of the hypothalamic pituitary axis. Now depending on what the target organ is,
there are different hormones that come from the hypothalamus. There are different
hormones or gonadotropins or tropic hormones that come from the anterior pituitary and the
posterior pituitary and they have different effects on the target organ. All of these systems
may have a role in normal menstrual cyclicity. You can see here the target end-organ hormone
production is definitely influenced by the anterior pituitary and the pituitary. Let's review
primary amenorrhea. In primary amenorrhea, you have never had a menstrual cycle. This is
pathologic if you are age 13 and have no secondary sexual characteristics. To remind you,
breast, axillary, and pubic hair are all secondary sexual characteristics. By age 15, even if you
have secondary sexual characteristics if you have no menses this is pathologic. Again, it's very
important to remember that the HPO axis must be intact for young woman to have a menstrual
cycle. If she has amenorrhea, something has gone wrong at the level of the HPO axis. It could be
the environment that is feeding back information into the CNS. The CNS then obviously corresponds
to the hypothalamus. The hypothalamus has to release gonadotropin-releasing hormone to the
anterior pituitary. The anterior pituitary will release gonadtropins, FSH, follicle-stimulating
hormone, and luteinizing hormone or LH to the ovary. The ovary then produces estrogen and
progesterone. The uterus is influenced by estrogen and progesterone and the withdrawal of both
of those hormones result in a menstrual cycle. Let's now go over the common causes that we
see in primary amenorrhea. If you have a patient that has breast development, you should consider
that their cause of primary amenorrhea may be Mullerian agenesis. There is a separate talk on
Mullerian agenesis or variance in another lecture if you'd like more information. Also, androgen
sensitivity can also present as primary amenorrhea. There is another lecture set where you
can learn more about complete and partial androgen sensitivity. Also, women may have anatomic
factors that actually prevent menses. One of those is a vaginal septum. They may also have
an imperforate hymen or they may overall have constitutional delay. If you have no breast
development, likely you will have a high FSH or follicle stimulating hormone. This can happen in
normal genetic female such as 46,XX. It can also happen in 46,XY individuals. Let's also now
talk about low FSH. You can typically have a low FSH with constitutional delay. This also happens
with prolactinomas and Kallmann syndrome. You may get tested about Kallmann syndrome so I will
spend a little time here. These patients usually have anosmia which means they cannot smell.
05:39
They usually have primary amenorrhea and will need assistance to become pregnant should they
like to become pregnant in the future. Other CNS pathology can also lead to a low FSH. Stress,
weight loss, and anorexia is typical to have a low FSH associated with it. Polycystic ovarian
syndrome can also have a normal to low FSH and again congenital adrenal hyperplasia may have
a low FSH as well. If you'd like to learn more about CAH or congenital adrenal hyperplasia, there
is a separate lecture set for that. I want to bring your attention to a really quick mnemonic to
remember the causes of primary amenorrhea. When I was a medical student, it was difficult for
me to remember but I'm going to give you a quick tip on how you can remember it. Remember XMAS.
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X is for 45,XO or monosomy associated with Turner syndrome. M is for Mullerian agenesis. Recall
that there is another lecture about Mullerian agenesis that you can review. A is for androgen
insensitivity syndrome. This is typical with complete androgen insensitivity syndrome. Again, you
can review this in another lecture set. Lastly, S is for Swyer syndrome. This is also referred to
as XY gonadal dysgenesis.