Hyperprolactinemia causes
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
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Overview
Causes
Hyperprolactinaemia may be caused by either disinhibition (e.g. compression of the pituitary stalk or reduced dopamine levels) or excess production from a prolactinoma (a pituitary gland adenoma tumour). A prolactin level of 1000–5000mIU/L could be from either mechanism, but >5000mIU/L is likely due to an adenoma with macroadenomas (large tumours over 10 mm diameter) having levels of up to 100,000mIU/L. Hyperprolactinemia inhibits gonadotropin-releasing hormone (GnRH) by increasing the release of dopamine from the arcuate nucleus of the hypothalamus (dopamine inhibits GnRH secretion), thus inhibiting gonadal steroidogenesis, which is the cause of many of the symptoms described below:
Physiological causes
Physiological causes (i.e. as result of normal body functioning): pregnancy, breastfeeding, stress, sleep.
Prescription drugs
Use of prescription drugs are the most common cause of hyperprolactinaemia. Prolactin secretion in the pituitary is normally suppressed by the brain chemical, dopamine. Drugs that block the effects of dopamine at the pituitary or deplete dopamine stores in the brain may cause the pituitary to secrete prolactin. These drugs include the major tranquilizers (phenothiazines), trifluoperazine (Stelazine), ,and haloperidol (Haldol); some antipsychotic medications like risperidone; metoclopramide (Reglan), used to treat gastroesophageal reflux and the nausea caused by certain cancer drugs; and less often, alpha-methyldopa and reserpine, used to control hypertension. Finally oestrogens and TRH.
Diseases
Prolactinoma or other tumors arising in or near the pituitary—such as those that cause acromegaly or Cushing's syndrome—may block the flow of dopamine from the brain to the prolactin-secreting cells, likewise division of the pituitary stalk or hypothalamic disease. Other causes include chronic renal failure, hypothyroidism and sarcoidosis. Some women with polycystic ovary syndrome may have mildly elevated prolactin levels.
Apart from diagnosing hyperprolactinaemia and hypopituitarism, prolactin levels are often determined by physicians in patients who have suffered a seizure, when there is doubt whether this was an epileptic seizure or a non-epileptic seizure. Shortly after epileptic seizures, prolactin levels often rise, while they are normal in non-epileptic seizures.
Idiopathic
In many patients elevated levels remain unexplained and may represent a form of hypothalamic-pituitary dysregulation.