Diagnosis of early hyperprolactinemia

Women don't know much about hyperprolactinemia, but it has a significant impact on women. Since hyperprolactinemia can cause menstrual disorders in patients, female friends should learn more about hyperprolactinemia. So, what are the methods for diagnosing early hyperprolactinemia?

1.Normal prolactin galactorrhea Some women have galactorrhea but normal blood PRL levels, which is called normoprolactinaemiclactorrhea. Normoprolactinaemiclactorrhea is not uncommon. According to foreign data, 28% to 55% of women with galactorrhea have normal blood PRL levels. Normoprolactinaemiclactorrhea is more common in women of childbearing age, and menstrual disorders are less common (about 1/3). Some patients' galactorrhea is related to normal pregnancy and breastfeeding. These women still have milk secretion after stopping normal breastfeeding, and it lasts for a long time. Others are related to oral contraceptives, and some are unknown. At present, the mechanism of the production of normoprolactin galactorrhea is not very clear. Some people have believed that there is a variant PRL in the patient's body, which has normal biological activity but cannot be measured by the usual radioimmunoassay, so the patient has galactorrhea but normal blood PRL level; some people believe that it may be caused by the increase in the levels of other hormones with prolactin activity (such as hGH) in the body. However, the above view has not been confirmed so far. At present, most scholars believe that it is caused by the increased sensitivity of patients to PRL. As for the reason for the increased sensitivity of the body to PRL, it is still unclear, and it may be related to the increase in PRL receptor levels. Johnston et al. believe that the PRL receptor levels of normal women have a physiological increase during pregnancy and lactation. After stopping lactation, the blood PRL and breast PRL receptor levels return to normal, but a small number of patients have some defects that keep the PRL receptor at a high level after stopping lactation. Therefore, although the blood PRL level is normal, there is still galactorrhea (the formation mechanism of those caused by oral contraceptives is similar to this). Some people use a small dose of bromocriptine (although the blood PRL level is normal) to reduce the blood PRL level to the lower limit of normal, and the galactorrhea symptoms can be improved, which also supports this view.

The characteristic of normoprolactinemic galactorrhea is the normal secretion of PRL. Not only does the patient have a normal basal PRL level, but the response to hypoglycemia and TRH is also normal, which can be used to distinguish it from galactorrhea caused by hyperprolactinemia.

2. Identification of the cause of hyperPRLemia After confirming the presence of hyperPRLemia, further etiological diagnosis should be made. First, the medical history should be inquired in detail to determine whether hyperPRLemia is caused by drugs. Secondly, liver and kidney function should be measured to determine whether hyperPRLemia is caused by cirrhosis or renal failure. The determination of TSH, T3, and T4 is necessary. If TSH, T3, and T4 are all significantly increased, it may be hyperPRLemia caused by pituitary TSH tumor; if TSH is increased and T3 and T4 are decreased, it may be hyperPRLemia caused by primary hypothyroidism. At the same time, blood GH, ACTH, and cortisol levels should be measured to determine whether GH tumors and ACTH tumors exist, because they can both cause hyperPRLemia. The determination of FSH/LH and α subunits is helpful for the diagnosis of gonadotropins and non-functional pituitary adenomas, which is also valuable for distinguishing the causes of hyperPRLemia.

Pituitary CT, MRI examination and blood PRL determination are of great significance for etiological diagnosis. Generally speaking, if CT and MRI have positive findings and the blood PRL level exceeds 9.1nmol/L (200ng/ml), the diagnosis of PRL tumor can be established. The blood PRL level is closely related to the size of the tumor. The blood PRL level of macroadenomas is mostly above 11.38nmol/L (250ng/ml), while that of microadenomas is mostly below 9.1nmol/L (200ng/ml). If the blood PRL level is only slightly to moderately elevated (below 9.1nmol/L) and CT and MRI show a macroadenoma, the tumor is often not a true PRL tumor, but a so-called pseudo-PRL tumor.

In recent years, 11C-labeled dopamine D2 receptor antagonists methylspiperone and raclopride have been used for PET imaging, which is not only of diagnostic significance, but also can predict the efficacy of dopamine receptor agonists. Generally speaking, those who can be imaged respond well to dopamine receptor agonists.