Hyperprolactinemia, which refers to the increased production of prolactin by the anterior pituitary, occurs physiologically during pregnancy, lactation, and periods of stress. Pathological hyperprolactinemia is most often the result of pituitary adenomas and less commonly due to primary hypothyroidism and/or dopamine antagonists (e.g., metoclopramide, haloperidol). Women with pathological hyperprolactinemia present with galactorrhea, loss of libido, infertility, menstrual dysfunction, and/or osteoporosis. Men generally present with loss of libido, erectile dysfunction, and/or gynecomastia. The diagnosis is confirmed by repeated measurement of early morning prolactin levels. After ruling out hypothyroidism, a cranial MRI should be performed to detect pituitary adenomas. Management consists of dopamine agonists (e.g., bromocriptine, cabergoline) and treating the underlying cause.
- Sex: ♀ > ♂
Prevalence: ∼ 0.4% of the general population
- Hyperprolactinemia is the most common form of hyperpituitarism.
Epidemiological data refers to the US, unless otherwise specified.
- Prolactin-secreting (prolactinomas)
- Damage to the hypothalamus and/or infundibular stalk
- Severe primary hypothyroidism: ↓ T3/T4 → ↑ TRH → ↑ prolactin
- Dopamine antagonists:
- Certain tricyclic antidepressants: e.g., clomipramine
- Catecholamine depletors: e.g., reserpine
- Dopamine synthesis inhibitors: α-methyldopa
- Oral contraceptive pills
- Opiate analgesics
- Histamine H2-receptor antagonists (cimetidine, ranitidine)
- Certain types of focal epilepsy: directly after temporal lobe seizures, due to close proximity to the hypothalamus.
- Chronic renal failure
- Stimulation of the reflex suckling arc in the chest wall (e.g., following chest wall surgery, post-herpes zoster)
- Physiological causes: stress, pregnancy, lactation, nipple stimulation, crying baby, sexual orgasm, sleep, exercise
Pituitary adenomas are the most common cause (∼ 50%) of pathological hyperprolactinemia!
- ↑ Prolactin → galactorrhea
- ↑ Prolactin → ↑ central dopamine (prolactin-inhibiting hormone) → suppression of GnRH → ↓ LH, ↓ FSH → ↓ estrogen, ↓ testosterone →
- For more details, see .
|Hormonal changes||Clinical features|
|↑ Prolactin|| |
|↓ LH + ↓ FSH|| |
|↓ Testosterone|| |
|↓ Estrogen|| |
- Basal prolactin level
- Prolactin stimulation test : a prolactinoma is the most likely diagnosis if the prolactin blood level does not increase
- TSH, T4 levels: to exclude
- In premenopausal women: pregnancy test
- Cranial contrast MRI: to rule out pituitary adenomas (see “Diagnostics” in )
- Dopamine agonists (treatment of choice): bromocriptine, cabergoline, quinagolide
- Treat the underlying cause