Question of the Week # 390

390)  A 28 year old woman has had amenorrhea for the past 4 months. She reports having regular menstrual cycles prior to these episodes. She is sexually active and a home pregnancy test was negative on two occasions over the last one week. She denies any excessive stress or physical activity. She has had headaches almost daily over the past three months. She denies any visual deficits. Her past medical history is significant for schizophrenia for which she is using risperdal for several years with good control of her disease. On examination, her vitals are stable. Body mass index is about 28 . There is milky discharge on breast examination. Pelvic exam is normal. Serum pregnancy test is negative. A serum prolactin level is 30mcg/ml (5 to 20 mcg/L). A serum Thyroid Stimulating Hormone and Follicle Stimulating Hormone level are within normal limit. An MRI of the brain reveals 10 cm lobulated mass in the anterior skull base. Which of the following is the initial step in evaluating this patient?

A) Repeat Prolactin after Serum Dilution

B) Discontinue Risperdal

C) Trans-Sphenoidal Resection of the Tumor

D) Pituitary Irradiation

E) Bromocriptine

25 Responses

  1. D-to reduce the tumor size

    • So do you think this is prolactinoma or non functioning adenoma? Why does she have milky discharge?

      • her elevated prolactin may be due to risperidone intake…..though i am not sure if it is prolactinoma….either way we go for surgery for a tumor as large as 10 cms

      • No because the first step in managing a large prolactinoma is still Bromocriptine even if prolactinoma is a visual threat! So your management would change based on whether this is prolactinoma or not. Because if it is not a prolactinoma, surgery is the choice. If it is a prolactinoma, bromocriptine always first whatever is the size and whatever is threat! ( The reason for treating even very big prolactinomas with dopamine agonists is that the risk and morbidity of trans-sphenoidal surgery is high and you do not want to do it when there is an efficient alternative. Bromocriptine is capable of shrinking even big tumors very fast. Surgery should only be considered if medical therapy cannot be tolerated or if medical therapy failed to reduce prolactin level/ shrink the tumor.
        So, it is important to know if this is indeed a prolactin secreting macroadenoma or non functioning adenoma since it changes our management dramatically!

      • before surgery irradiation to decrease the tumor size

  2. ccccccc

  3. B) discontinue risperdal
    Risperdal is dopamine antagonist and cause hyperprolactinemia.
    Then, Bromocriptine.

  4. Is it 10 cm or 10 mm?

    • 10 cm. That’s the clue and the issue in this question since it’s size does not seem to correlate with prolactin level. Macro-prolactinomas should typically cause prolactin levels in thousands ( may be > 5000 at this size) But why then galactorrhea? Is it still macro prolactinoma? how would you know? what is happening in this question?

  5. A) Repeat Prolactin after Serum Dilution – the serum levels are too low for such big tumour

    • There you go! So, what happened in this case? Why are you diluting the serum?

      • Falsely low serum prolactin level.
        Serum prolactin level can be apparently low caused by a high dose hook effect in chemiluminometic assay in invasive macroprolactinoma.
        Therefore, to rule out that condition, measure prolactin level after serum serial dilution, If it is high, macroprolactinoma.
        If serum prolactin is low, non functioning adenoma.

  6. C.
    10cm is too big to reduce it wid bromocriptne and it shud b prmptly trtd

  7. Very high prolactin levels interfere with the prolactin assay resulting in low readings – High -dose Hook effect

    • Great!! Physicians should recognize this because mislabeling a tumor as “non functional” based on non-correlation between degree of prolactin elevation and size of tumor will lead us to consider unnecessary surgery ! Here is an additional reference

      • A nice discussion. I was wondering that if you put her on bromocriptin and, I assume, take her off rispedral, her schizofrenia will relaps. Could you comment on it? Thanks

      • Good question, although they will not ask you bromocriptine effects on schizphrenia , it is indeed a clinical dilemma you may face in practice. Studies have shown adding bromocriptine will not aggravate schizophrenia. in fact, it may help reduce negative symptoms of schizophrenia like social withdrawal. This is a good article if you wish to read :

    • So once we confirm abnormally high levels of serum Prolactin..we can go ahead and treat her with bromocriptine instead of surgery which is the treatment for non-functioning adenomas

  8. E


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