Hyperprolactinaemia
[1] Hyperprolactinemia, characterized by abnormally high levels of prolactin, may cause galactorrhea (production and spontaneous flow of breast milk), infertility, and menstrual disruptions in women.Together with estrogen, progesterone, insulin-like growth factor-1 (IGF-1), and hormones from the placenta, prolactin stimulates the proliferation of breast alveolar elements during pregnancy.Prolactin also self-regulates through a counter-current flow in the hypophyseal pituitary portal system, which triggers the release of hypothalamic dopamine.[1] Women who are not pregnant or nursing may also unexpectedly begin producing breast milk (galactorrhea), a condition that is not always associated with high prolactin levels.[10] Unlike women, men do not experience reliable indicators of elevated prolactin such as menstrual changes, to prompt immediate medical consultation.[11] For instance, symptoms such as loss of libido and sexual dysfunction are subtle, arise gradually, and may falsely indicate a different cause.[11] Many men with pituitary tumor–associated hyperprolactinemia may forego clinical help until they begin to experience serious endocrine and vision complications, such as major headaches or eye problems.Impaired bone mineral density (BMD) serves as an "end organ" marker, reflecting the full extent of the disease.[3] As a result, hyperprolactinemia may be caused by disinhibition (e.g., compression of the pituitary stalk or reduced dopamine levels) or excess production.[19] Physiological (i.e., non-pathological) causes that can increase prolactin levels include: ovulation, pregnancy, breastfeeding, chest wall injury, stress, stress-associated REM sleep, and exercise.These drugs include the typical antipsychotics: phenothiazines such as chlorpromazine, and butyrophenones such as haloperidol; atypical antipsychotics such as risperidone and paliperidone; gastroprokinetic drugs used to treat gastro-esophageal reflux and medication-induced nausea (such as that from chemotherapy): metoclopramide and domperidone; less often, alpha-methyldopa and reserpine, used to control hypertension; and TRH.[18][32] Hyperprolactinemia develops in one-third of individuals with chronic kidney disease due to impaired renal clearance and regulation.[35] Some inflammatory conditions, such as rheumatoid arthritis and systemic lupus erythematosus, are also linked to higher prolactin levels in certain regions.Prolactin levels less than 100 ng/mL may suggest drug-induced hyperprolactinemia, macroprolactinemia, nonfunctioning pituitary adenomas, or systemic disorders.[3] In patients with mildly elevated serum prolactin levels, secondary causes such as pituitary adenomas can be ruled out[40] Elevated prolactin blood levels are typically assessed in women with unexplained breast milk secretion (galactorrhea) or irregular menses or infertility, and in men with impaired sexual function and milk secretion.[42] While a plain X-ray of the bones surrounding the pituitary may reveal the presence of a large macroadenoma, small microadenomas will not be apparent.FSH in men is responsible to stimulate sperm production and LH is responsible for the stimulation of testosterone; with the inhibition of GnRH, FSH, and LH, physical signs that show in men include reduced sex drive and infertility, these symptoms suggests the onset of hyperprolactinaemia.[2] Although this can result in high prolactin levels in some assay tests, macroprolactin is biologically inactive and will not cause symptoms typical of hyperprolactinemia.[47] In the case of diagnosing hyperprolactinaemia, a weak positive line can often lead to a false negative result and increase the risk of misdiagnosis of the condition or a potential pituitary adenomas.There are many underlying factor that can cause hyperprolactinemia, some of them are hypothyroidism (disorder in which thyroid glands has a reduced thyroid hormone production), drug-induced hyperprolactinemia (such as antidepressant medication, antihypertensive medication and medication that can promotes bowel motility), hypothalamic disease(disorder caused by damage in the hypothalamus), idiopathic hyperprolactinemia( no recognized cause are present since there is no pituitary or central nervous disease present), macroprolactin (complex form of prolactin in the blood), or prolactinoma (non-cancerous tumor in the pituitary gland).[51] No treatment is required in asymptomatic macroprolactin and instead, serial prolactin measurements and pituitary imaging is monitored in a regular follow-up appointments.[3] In most cases, medications that are dopamine agonists, such as cabergoline,[52] quinagolide and bromocriptine (often preferred when pregnancy is possible), are the treatment of choice used to decrease prolactin levels and tumor size upon the presence of microadenomas or macroadenomas.According to SUCRA (Surface Under the Cumulative Ranking) and SMAA (Stochastic Multicriteria Acceptability Analysis), quinagolide was found to be the best treatment for women since it can help reduce menstrual irregularities, in addition bromocriptine was shown to be more effective in the treatment for galactorrhea (breast milk production unrelated to pregnancy), and cabergoline was the safest medication as it did not show any alarming side effects.[57] Other dopamine agonists that have been used less commonly to suppress prolactin include dihydroergocryptine, ergoloid, lisuride, metergoline, pergolide, and terguride.