What are the signs of hyperprolactinemia?

Hyperprolactinemia is the most common pituitary disease, with galactorrhea and hypogonadism as prominent manifestations. Female patients may experience decreased libido and loss of sexual desire, which will be relieved after treatment as PRL levels decrease. Male patients mainly experience decreased libido and impotence, and in severe cases, body hair loss, testicular atrophy, reduced sperm count, and even azoospermia may occur.

Cause: Under physiological conditions, inhibitory regulation is dominant in the regulation of prolactin. Any factors that interfere with the synthesis of dopamine in the hypothalamus and its transport to the pituitary gland and the interaction between dopamine and its receptors can weaken inhibitory regulation and cause hyperprolactinemia. Common causes can be summarized into four categories: physiological, pathological, pharmacological and idiopathic. 1. Physiological prolactin is a stress hormone that is secreted in a pulsed manner and is higher at night than during the day. It reaches a peak in the luteal phase of the female menstrual cycle and is at a low level in the follicular phase. It increases significantly at full term and after delivery. In addition, prolactin secretion increases significantly under stressful conditions, and high-protein diets, exercise, tension and sexual intercourse, breastfeeding, nipple stimulation and sleep disorders can all lead to elevated serum prolactin levels. 2. Pharmacological Any drug that interferes with dopamine synthesis, metabolism, reabsorption or blocks the binding of dopamine to receptors can cause hyperprolactinemia, but it is generally lower than 4.55nmol/L. Common drugs include estrogen, dopamine receptor blockers (such as antipsychotics, sedatives, antihypertensive drugs reserpine, monoamine oxidase inhibitors such as phenelzine, α-methyldopa), H2 receptor blockers (such as gastrokinetic drugs metoclopramide, metoclopramide and cimetidine, etc.), drugs that inhibit dopamine metabolism (such as opioid preparations), etc. 3. Pathological causes are mainly seen in hypothalamic-pituitary diseases, systemic diseases, ectopic prolactin production and other causes. ⑴ Hypothalamic lesions: such as craniopharyngioma, glioma, sarcoidosis, tuberculosis, etc. compressing the pituitary stalk; impaired hypothalamic function after cranial radiotherapy. ⑵ Pituitary diseases: prolactin-producing pituitary microadenomas; pituitary somatotropin adenomas, adrenocorticotropic hormone adenomas; empty sella syndrome, sarcoidosis, granulomatous disease, inflammatory lesions. ⑶ Systemic diseases: primary hypothyroidism; chronic renal failure; severe liver disease, cirrhosis, hepatic encephalopathy; certain tumors such as adrenal adenoma, bronchial carcinoma, ovarian cystic teratoma. ⑷ Neurogenic: chest wall lesions, herpes zoster neuritis and breast surgery, etc. ⑸ Others: polycystic ovary syndrome. 4. Idiopathic Idiopathic hyperprolactinemia refers to elevated serum prolactin, usually <4.55nmol/L, negative pituitary, central nervous and systemic examinations, and accompanied by symptoms such as lactation, oligomenorrhea, and amenorrhea. The onset may be related to the heteromorphic structure of the prolactin molecule, and the course of the disease is self-limited.

Clinical manifestations 1. Lactation is the main clinical manifestation of hyperprolactinemia. About 2/3 of patients will lactate during non-pregnancy and non-lactation periods. Male patients may also develop breast development and lactation. The secreted milk is colostrum-like or watery or serous, yellow or white. In most cases, the secretion volume is not large. Usually, milk will only flow out when squeezed. In severe cases, it may flow out on its own. Although lactation is closely related to increased blood prolactin levels, the amount of lactation has nothing to do with the degree of increased prolactin levels. Lactation is more common in patients with pituitary microadenomas, accounting for about 70%; only 30% of non-tumor hyperprolactinemia will lactate. 2. Menstrual disorders and amenorrhea patients may show menstrual disorders, secondary amenorrhea, decreased libido, and severe cases may have genital atrophy and osteoporosis. When patients lactate, have reduced menstrual volume or even amenorrhea, it is called amenorrhea-galactorrhea syndrome. Patients with polycystic ovary syndrome often have hyperprolactinemia. In addition to elevated prolactin, blood androgen levels are also elevated. They also have obesity, hirsutism, acne, and oligomenorrhea. 3. Infertility Most hyperprolactinemia is caused by pituitary microadenomas. About 90% of patients show oligomenorrhea or amenorrhea. They can also show infertility, accounting for about 70%. Men may show decreased libido, decreased sperm quality, and infertility. 4. Other patients with pituitary or intracranial tumor hyperprolactinemia may also have headaches, blurred vision or visual field loss, blindness, diplopia, and hypopituitarism; those caused by growth hormone adenomas may also have gigantism and acromegaly; those caused by adrenocorticotropic hormone adenomas may also have Cushing's disease; those caused by thyrotropinomas may also have hyperthyroidism and non-functional tumors.