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Prolactinoma

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VIDEO TRANSCRIPT

Hey, whats going on guys.  Today I want to do a case presentation regarding a prolactinoma.  So, this is a little background.  This is a patient that I’v actually been seeing for a little over a year now, and I just recently saw her a couple of days ago and I thought this would be an interesting case, and there are some good learning points to learn from this patient as well.  So, the theme is going to be prolactinoma.  Lets go back to when I first met this patient.  She initially came in because she complained of not having a menses for 2 years. She’s a 30 year old female and the last time she’s had a physical of any type was probably around 4 or 5 years ago.  She thought it was a little odd that she hadn’t had a period, but never thought it was that big of a deal; she never thought to get it checked out and thought it would eventually come.  The reason she actually came in apart from not having a period for two years, was that she was having increased headaches.  On further questioning she started describing visual disturbances.  What do visual disturbances mean for this patient?  She was having blurry vision, and she was actually complaining of double vision.

So, you now have a patient that does not have a menses for two years, headaches, and visual disturbances.  The first thing that should pop into your mind, is some kind of mass lesion, and the first mass lesion that should pop into your mind is a prolactinoma.  Its very common.  About 20% of patients that come in with amenorrhea actually have a prolactinoma or an elevated prolactin level; it doesn’t necessarily need to be from a prolactinoma.  These are the things that were bothering her: she had the headaches, the visual disturbances, and the absence of menses.  Alright, so, what is the workup and how did we go about diagnosis this prolactinoma.  Well, the first thing you need to do in any patient coming in without a period, even in a missed period or two missed periods is an HCG.  You can do a simple urine pregnancy test, you don’t necessarily need to do the quant, because if she had a pregnancy after two years, this would be positive. So, a urine pregnancy test is more than enough.  The first three labs that should be ordered in anyone suspected of having amenorrhea should be an FSH, prolactin, and TSH.  Like I said, about 20% of patients who come in with amenorrhea will have an elevated prolactin level; very important.  TSH is important in working up hypothyroidism, and FSH is important in working up hypogonadism.  So, obviously HCG was negative.  TSH was normal, however, for you to be aware, sometimes hypothyroidism can actually cause an elevated prolactin level.

Heres what you need to know about prolactin.  Prolactin can be elevated due to a variety of things.  Even stress can elevate prolactin levels.  Nipple stimulation can elevate prolactin levels.  So what you need to be aware of is the actual number.  In the majority of labs a level over 20 is considered abnormal.  Anything under 100 can be due to a variety of causes, such as medications, stress, nipple stimulation, etc.  So, if you have a very mildly elevated prolactin level, say around 40 (which is not that much), I would urge you or advise you to just go ahead and repeat that prolactin level another time.  Also, hypothyroidism can elevate the prolactin level (mildly).  You don’t need to do an MRI because once you take care of the hypothyroid, the prolactin level will go right back down to normal.  Now, anyone who has a prolactin level over 100, needs to get a different type of work up.  These patients really need to have an MRI to look for mass lesions because the majority of medications and the majority of other causes of an elevated prolactin will not elevate the prolactin over 100.

Alright, so, what were her results?  Her results showed that she actually had a prolactin level of 150; 150 warrants an MRI.  She had an MRI done, and we discovered a 15mm macro adenoma.  Anything over 10mm is considered a macro adenoma.  Anything under 10mm is considered a micro adenoma.  So, thats really the cut off point for that.  There is also one little caveat that you need to be aware of: the hook effect.  These are falsely low values of a prolactin level.  So, when you have prolactin levels under 200, you can have whats called the hook effect.  These are extremely large macro adenomas that cause an extremely elevated prolactin level into the thousands.  What happens is that these elevated prolactin levels actually over saturate the assays that are used for prolactin measurement, and give a false low value.  So, you need to be aware of this hook effect, and you can go around this hook effect by repeating or just ordering the MRI if they have symptoms like visual disturbances or headaches. You can actually do a dilution and order a special assay for that.  But hers was pretty straight forward with a prolactin of 150 and an MRI showed a macro adenoma, so now we have the diagnosis of a prolactinoma.

So, how do we go ahead and treat these patients?  The first thing you need to do is give a dopamine agonist, this is first line treatment, and the most common first line treatment is going to be cabergoline.  Cabergoline is really well tolerated without a lot of side effects.  Theres only one dose and it only comes in .5mg.  So, the way we dosed this patient was half a tab twice a week, and thats it.  She actually started to improve after a few weeks of treatment and by six months of treatment, she actually had complete resolution, she had a menses, she felt good, her headaches were gone; she was actually feeling so much better.  What I recommend is, once you start these patients on cabergoline, to really check the prolactin level every month.  This patient was not as diligent, this patient does not have insurance, so she was coming in every month or every two months.  It was a little bit more difficult, but finally we got the prolactin down to about 20, which is completely normal and its great!

Now, for macro adenomas, I probably wouldn’t repeat the MRI for a year after doing cabergoline and getting the prolactin levels down to normal.  So, its been a year later.  She’s scheduled for an MRI, she’s been scheduled for an MRI actually, but she just has yet to go.  The reason again, is that this patient does not have insurance, so its a little bit more difficult for this patient.  You kind of have to work around these things.  Now, what you want to do is, if the prolactinoma has decreased or has completely been eliminated, continue the cabergoline for another year.  There are some studies that have shown after two years of treatment with normal serum prolactin levels and in the absence of prolactinoma, you can go ahead and try to take these patients off the cabergoline.  There is a small risk of reoccurrence, but the majority will be symptom free, and the prolactin level will not rise back to the original point in time.  So, this was a little case presentation of prolactinoma.  Thank you guys for joining me, I hope you guys learned something.  Well try and continue to do these videos, these little five minute videos to try and get you as prepared as possible and also to give you a little look as to the clinical aspect.  What its like to actually manage patients.  Alright guys, until next time, take care!

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Andrew
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