Hyperprolactinaemia

Overview

Hyperprolactinaemia is a medical condition characterized by elevated levels of prolactin in the blood. Prolactin is a hormone produced by the pituitary gland that primarily regulates lactation (milk production) in women. However, it also plays roles in reproductive and metabolic functions in both sexes. Elevated prolactin levels can interfere with normal reproductive hormone balance, leading to menstrual irregularities, infertility, sexual dysfunction, and other systemic effects.

Causes

Hyperprolactinaemia can result from a variety of physiological, pathological, and pharmacological factors, including:

• Physiological causes: Pregnancy, breastfeeding, stress, sleep, and intense exercise

• Pituitary tumors: Prolactinomas (benign tumors of the pituitary gland that secrete prolactin)

• Medications: Antipsychotics, antidepressants, antiemetics (e.g., metoclopramide), and certain blood pressure drugs

• Hypothyroidism: Low thyroid hormone levels increase TRH, which can stimulate prolactin production

• Chronic kidney disease and liver cirrhosis: Reduced clearance of prolactin

• Chest wall trauma or surgery: Can stimulate prolactin release via neural pathways

Symptoms

The symptoms of hyperprolactinaemia vary depending on sex, age, and underlying cause. Common signs and symptoms include:

In Women:

• Irregular or absent menstrual periods (amenorrhea)

• Galactorrhea (milky nipple discharge not related to breastfeeding)

• Infertility

• Decreased libido

• Vaginal dryness and painful intercourse

In Men:

• Reduced libido

• Erectile dysfunction

• Infertility

• Gynecomastia (breast enlargement)

• Decreased muscle mass and energy

In Both Genders (with large pituitary tumors):

• Headaches

• Visual disturbances (due to compression of the optic chiasm)

Diagnosis

Diagnosis of hyperprolactinaemia involves laboratory tests and imaging studies to identify the underlying cause. Key steps include:

• Serum prolactin levels: Elevated levels confirm the diagnosis

• Thyroid function tests: To rule out hypothyroidism (TSH and free T4)

• Pregnancy test: In women with amenorrhea

• Renal and liver function tests: To check for systemic causes

• MRI of the pituitary gland: To detect prolactinomas or other pituitary lesions

Medications should also be reviewed, as many drugs can elevate prolactin levels.

Treatment

Treatment depends on the cause, severity, and patient-specific factors such as fertility goals. Management strategies include:

• Discontinuation of offending drugs: When safe and feasible

• Treatment of hypothyroidism: With levothyroxine if TSH is elevated

• Dopamine agonists: Such as cabergoline or bromocriptine to reduce prolactin levels and shrink prolactinomas

• Surgery: Transsphenoidal resection may be needed for large or resistant pituitary tumors

• Radiation therapy: In rare cases where surgery and medication are not effective

Regular monitoring of prolactin levels and MRI imaging is necessary for ongoing management.

Prognosis

The prognosis for hyperprolactinaemia is generally favorable with appropriate treatment. Most patients respond well to dopamine agonists, which can normalize prolactin levels, restore fertility, and reduce tumor size. Prolactinomas are often manageable without surgery. However, recurrence can occur, especially after discontinuing therapy. Lifelong monitoring may be required in some cases, particularly when large tumors or persistent hormone elevation is present.