From the Guidelines
Hyperprolactinemia is primarily caused by pituitary adenomas, hypothyroidism, renal and hepatic impairment, and medications that stimulate prolactin secretion or antagonize dopamine's inhibitory effect.
Causes of Hyperprolactinemia
- Pituitary adenomas: These are the most common cause of hyperprolactinemia, with prolactin levels often above 4,000 mU/l (188 μg/l) in pediatric patients 1.
- Hypothyroidism: Severe primary hypothyroidism can cause hyperprolactinemia due to compensatory thyrotropin-releasing hormone hypersecretion and pituitary hyperplasia, with a reported prevalence of 43% in women and 40% in men with frank primary hypothyroidism 1.
- Renal and hepatic impairment: Hyperprolactinemia is common in patients with chronic kidney disease (30-65%) and severe liver disease due to increased prolactin secretion and reduced renal clearance 1.
- Medications: Various medications, including antipsychotics, antidepressants, and opioids, can cause hyperprolactinemia by stimulating prolactin secretion or antagonizing dopamine's inhibitory effect 1.
Effects of Hyperprolactinemia
- Galactorrhoea: Spontaneous milk production, which can occur in both men and women.
- Oligo-amenorrhoea: Infrequent or absent menstrual periods in women.
- Gynaecomastia: Enlargement of breast tissue in men.
- Loss of libido: Decreased sex drive.
- Delayed growth and puberty: Hyperprolactinemia can affect growth and development in children and adolescents.
- Bone mineral density loss: Prolactinomas can lead to low bone mineral density, particularly if left untreated or if treatment is delayed 1. It is essential to measure prolactin levels in patients with signs or symptoms of hyperprolactinemia and to consider serial dilutions of serum for prolactin measurement in patients with large pituitary lesions and normal or mildly elevated prolactin levels 1. Additionally, baseline macroprolactin levels should be assessed in patients with mildly or incidentally elevated serum prolactin levels to rule out macroprolactinemia 1. Treatment with dopamine agonists, such as cabergoline, can effectively manage hyperprolactinemia, and gradual dose reduction can be considered after at least 2 years of medical therapy with normalized prolactin levels and no visible residual prolactinoma on MRI 1.
From the Research
Causes of Hyperprolactinemia
- Physiological causes, such as pregnancy and lactation 2
- Pharmacological causes, such as certain medications 3, 2
- Pathological causes, including pituitary tumors (prolactinomas) and other sellar/parasellar masses 3, 4, 2, 5, 6
- Other causes, such as primary hypothyroidism and miscellaneous causes 5, 6
Effects of Hyperprolactinemia
- Hypogonadism, leading to reproductive dysfunction and infertility 4, 2, 5, 6
- Galactorrhea, a typical symptom of hyperprolactinemia 4, 2, 5
- Osteoporosis, due to estrogen deficiency in women with hyperprolactinemic amenorrhea 4, 2, 5
- Mass effects of pituitary tumors, such as neurologic symptoms and visual field defects 5, 6
- Metabolic and immune system implications, which are still being researched 3
Diagnosis and Treatment of Hyperprolactinemia
- Diagnostic evaluation involves exclusion of other causes, laboratory tests, and diagnostic imaging of the sella turcica 5, 6
- Treatment aims to normalize prolactin levels, restore gonadal function, and reduce the effects of chronic hyperprolactinemia 3, 2, 5, 6
- Dopamine agonists, such as bromocriptine and cabergoline, are the treatment of choice for most patients 2, 5, 6
- Transsphenoidal surgery may be necessary for patients who are intolerant of or resistant to dopamine agonists, or when hyperprolactinemia is caused by non-prolactin-secreting tumors compressing the pituitary stalk 5, 6