#prolactinomas

Prolactin is secreted by the pituitary gland in significant amounts post-partum and during lactation.  It functions to inhibit ovarian function which will reduce estrogen, inhibit ovulation, and therefore it is "nature's birth control" for most women who are nursing full time.  While men don't nurse, any elevation in PRL is going to have a similar inhibitory effect on testosterone causing secondary sex issues.

Both men and women get prolactinomas but women present much earlier and usually have microadenomas.  Men usually present so late that they have macroadenomas by the time they are discovered.

Symptoms of a prolactinoma can be subtle early on.  Women usually present with amenorrhea, think they are pregnant because they also may have galactorrhea.  Their pregnancy test is negative; you find they are not hypothyroid (TSH is normal); so you check a prolactin level and it is elevated.

Men are trickier because they obviously don't get amenorrhea.  Their main symptom is decreased libido (women get decreased libido too, but usually don't present with that complaint -- amenorrhea happens earlier). (men with galactorrhea usually present to find out what's up:)

a little side note --- decreased libido is NOT erectile dysfunction!!!  any man with testosterone ought to have libido!!!  Prolactinoms can cause both decreased libido and eventually ED because the patient will have very low levels of testosterone and testicles will get smaller.

So -- my patient --a 24 year old previously healthy female presented to the ER with chief complaint of headache; she also had some problems with her peripheral vision.  She could speak no English, so it was a very tricky history even with interpreter.  I went back through her chart and saw that the only time she had ever presented to the clinic was for complaints of decreased libido.  As a matter of fact, she presented three times with decreased libido as her only complaint.  Her menses was reported as irregular.  She had no labs performed, but began SSRI's for depression.

I examined her, and was mildly concerned about some peripheral field changes, but all I had was the Bates' finger wiggling exam which is a very crude measure of peripheral fields of vision.  Still, having a patient specifically mention problems with her peripheral vision is very unusual, and very uncommon.

I examined her and that was the only questionable finding.  I got a pg test, it was negative.  TSH was normal.  CBC and CMP are normal.  HA improved with ibuprofen.

I got a PRL, but results were not available, and I discharged her to f/u with her PMD.

A normal PRL for a woman is (in my hospital) 4-16.  

A microadenoma for any patient is PRL < 200.

A macroadenoma for any patient is PRL > 200.

Hers was 780!!

Clinical Intervention

She needs an MRI.  She needs to see optho for formal peripheral fields of vision testing and dilated optic nerve/cup exam.

She needs to see Endocrinology and Neurosurgery.

She will start on Cabergoline twice a week --- which will help to shrink the tumor.

If she has significant visual defects, she will need surgery. Vision lost will not be regained.

These are quite common, folks --- keep it in your differential for all women with amenorrhea who are not pregnant (hypothyroidism is more common, but this is right up there too)  Keep it in your differential for all men presenting with decreased libido.  They need testosterone levels, TSH and PRL done.

What about that Dopamine connection?

Patients on psychotropic drugs may get elevation of PRL (in the 40-50 range) due to dopaminergic effects.  Risperidone being one of the most common. 

If the patient does not want to be pregnant, it is not an issue and the patient could probably stay on the meds.  Best clinical intervention is to consult the psychiatrist to discuss.