Back To CoursePathophysiology Textbook
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Heather has taught reproductive biology and has researched neuro, repro and endocrinology. She has a PhD in Zoology/Biology.
Okay ladies and gents, we all know the deal… Every month women go through that wonderful time period known as PMS! Okay, well PMS actually refers to the symptoms of a woman's monthly menstrual cycle, which normally occurs once every 28 days or so.
But what happens when that cycle is disrupted? And how does a woman lose her menstrual cycle? Well, before we get into that, let's quickly review what happens under normal circumstances, when everything is working correctly.
See, normally the brain, the ovaries and the uterus all communicate with each other using hormones to make sure that:
But sometimes this communication process goes wrong and one or more of our hormones doesn't send out the right signals. When this happens we can get interference with both egg production and preparation of the uterus. Like when you are texting and autocorrect puts in a word you didn't mean to type, or when you send a message but it doesn't go through the network because it's down! Then your message gets messed up and the person on the other end doesn't get the correct message or information. This can happen in your body too but instead of text messages, it's the level of hormones being secreted that are messed up.
When this happens a woman's menstrual cycle can stop, a condition known as amenorrhea or the failure to menstruate. I know that's a big word, so let's break it down. The prefix 'a-' means 'without' and 'menorrhea' starts with the same few letters as 'menstrual', right? So we get 'without' and 'menstrual'. Now girls, you may be thinking 'Amen for Amenorrhea' because you don't have to deal with PMS anymore, but this also means that something could be wrong with the reproductive system.
There are two types of amenorrhea: primary and secondary. Let's start with primary amenorrhea. This is when a female fails to begin her monthly menstrual cycle by the age of 16. Now, in biology when you hear a syndrome described as primary, it usually refers to the cause of the condition. Most primary syndromes are caused by a physical problem with a tissue or an organ. So, primary amenorrhea can be caused by an anatomical problem with the female's reproductive system or her HPG axis.
First up gonadal dysgenesis, or more simply put, abnormal development of the gonads, in this case the ovaries, because we are talking about females. Abnormal ovarian development can lead to the failure to produce the hormones estrogen and progesterone. And, just like we broke down the word 'amenorrhea', we can also break down the word 'dysgenesis'. Now, what other words does the prefix 'dys-' appear in? How about 'dysfunctional', which means what? 'Not working properly', right? And what about the term 'genesis'? Well there is generate and generation and well, Genesis, or the first book of the Bible. Any idea what they all have in common? They all refer in some way to a beginning or a creation and development of something. A new idea, a new generation and the beginning of a book. So by this, you can probably infer that dysgenesis refers to abnormal creation or development of something, and in this case we're talking about a woman's ovaries.
Okay, so number one? Abnormal ovaries!! Or, really abnormal development of any part of the female reproductive system could also cause primary amenorrhea. Other causes can include a disorder in the hypothalamic-pituitary-gonadal axis, or the HPG axis, which controls the hormone signaling pathways of reproduction that we talked about earlier and allows the brain to communicate to the ovaries using hormones (or its own version of text messaging).
And sometimes certain reproductive conditions or developmental disorders, such as testicular feminization, can also be a cause. This is a developmental disorder that occurs during fetal development. In females with testicular feminization, it's pretty much exactly as it sounds. They actually have testes, not ovaries. I know, sounds pretty unusual, doesn't it? But believe it or not, it can happen! You see these women are born with a Y chromosome and develop testes as a fetus. However, their body cannot recognize the testosterone being produced by the testes and so the rest of their body develops just like any normal female's would. This is because testosterone is essential in masculinizing the male body, and the female body develops in the absence of testosterone. But there is one key difference! These females don't have any ovaries or uterus - their internal reproductive tract is missing!
So you can see, without ovaries and without a uterus, they wouldn't have the ability to menstruate.
These are just some of the main causes of primary amenorrhea, but what about secondary?
Well, secondary amenorrhea is also the cessation, or stopping, of menstruation, but in this case it refers to the cessation of menstruation for at least 6 months in a woman who has already had established and normal menstrual cycles.
Now, unless the female is pregnant, in which case the amenorrhea is normal, or she is on birth control making a choice to stop her cycle, the causes are usually related to the function of the HPG axis, the ovaries and the uterus. And, since we know all these structures work together that means that if one or more of them isn't working properly, it can disrupt the menstrual cycle.
What do I mean by not working properly? Well, say the HPG axis, which secretes all those hormones needed for reproduction, releases levels that are too low, or maybe doesn't release the hormones at all. There may be nothing wrong with how the organs developed but just with how they are working because they aren't receiving the right signals or messages from the brain or other parts of the HPG axis.
Perhaps there is a tumor in the pituitary, or maybe an infection. Even some disorders like anorexia, strenuous exercise or obesity can interfere with how the HPG axis functions.
Another example? Well, maybe the ovaries are having difficulty maturing eggs for ovulation. This could change the amounts of estrogen and/or progesterone that are sent to the uterus. Without the right amounts of these hormones, the uterus cannot build up and shed tissue in a normal way.
Basically, anything that can interfere with the levels of hormones in the HPG axis can also interfere with the ability of the uterus to menstruate properly, and when menstruation ceases all together, we get secondary amenorrhea.
So what can be done? Can these problems be fixed? Well, for both types of amenorrhea, treatment all depends on the underlying cause and therefore, will vary from individual to individual. Sometimes it's as simple as taking hormone treatment, but can be as complicated as surgery. So how do doctors know what treatment is right? It all depends on the source of the problem! If the cause is primary, it may require a surgical approach to correct the problem. If it is secondary, sometimes hormone treatment can be used to try and restart normal menstrual patterns.
If causes include something like a pituitary or ovarian tumor, then this can often be approached surgically with hopes that removal will restore normal function. In cases where the cause is someone's life habits, then changing diet or exercise patterns may help. In all cases, treatment will depend on the cause and therefore, can vary greatly from one patient to the next.
So remember, amenorrhea is the failure of a female to menstruate. If the condition is primary amenorrhea, then the patient fails to show a normal menstrual period by the age of 16. This condition is often caused by a physical abnormality in the reproductive tract or the HPG axis.
This can include conditions like:
But if the amenorrhea occurs after a female has progressed through a normal menstrual cycle and then cessation of her cycle occurs for 6 months or more, it is considered secondary amenorrhea.
Causes of secondary amenorrhea are related more to the function of the HPG axis rather than a physical abnormality. In this case, the structures develop normally but fail to work properly, leading to abnormal or a lack of normal hormone production necessary for menstruation.
In each patient, treatment will vary and will depend on the cause of the condition. Surgical intervention is most commonly used to address primary amenorrhea, while hormone replacement or lifestyle changes are used to treat secondary amenorrhea.
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Back To CoursePathophysiology Textbook
20 chapters | 274 lessons