What does hyperprolactinemia in a non-pregnant woman mean?

Evaluation and Management of Hyperprolactinemia in Non-Pregnant Women

A prolactin level of 47 ng/mL in a non-pregnant woman indicates pathological hyperprolactinemia that requires further evaluation to identify the underlying cause, with prolactinoma being the most common etiology once medication effects, hypothyroidism, and other secondary causes are excluded. 1, 2

Significance of Prolactin Level 47 ng/mL

The normal reference range for serum prolactin in non-pregnant females is 3.0-30.0 ng/mL according to the American College of Endocrinology 1. At 47 ng/mL, this value is significantly elevated and requires clinical investigation.

Potential Causes of Hyperprolactinemia

Physiologic Causes (to be excluded)

• Pregnancy (already excluded in this case)
• Breast stimulation
• Stress
• Sleep
• Exercise

Pathologic Causes

1. Pituitary disorders:

   • Prolactinoma (most common pathologic cause)
   • Other pituitary adenomas causing stalk compression
   • Empty sella syndrome

2. Medications (common iatrogenic cause):

   • Antipsychotics (especially typical antipsychotics and risperidone) 3
   • Antidepressants (particularly those with serotoninergic activity) 3
   • Antihypertensives (methyldopa, verapamil)
   • Opiates
   • Metoclopramide and other prokinetics
   • H2-receptor antagonists 3

3. Systemic disorders:

   • Primary hypothyroidism
   • Chronic renal failure
   • Cirrhosis
   • Chest wall lesions/trauma

Diagnostic Approach

1. Confirm true hyperprolactinemia:

   • Repeat measurement to rule out stress-induced elevation
   • Collect sample in the morning after fasting

2. Exclude secondary causes:

   • Medication review
   • Thyroid function tests (TSH, free T4)
   • Renal function tests
   • Pregnancy test (if applicable)

3. Imaging:

   • MRI of the pituitary with contrast is the preferred imaging modality when secondary causes are excluded 2
   • CT scan if MRI is contraindicated

Clinical Manifestations to Assess

• In women:

  • Oligomenorrhea/amenorrhea
  • Galactorrhea
  • Infertility
  • Decreased libido
  • Vaginal dryness
  • Osteopenia/osteoporosis (long-term)

• In men:

  • Decreased libido
  • Erectile dysfunction
  • Infertility
  • Gynecomastia (less common)
  • Osteopenia/osteoporosis (long-term)

Treatment Approach

1. Address Underlying Cause

• Discontinue causative medications if possible
• Treat hypothyroidism if present
• Manage other systemic disorders

2. Pharmacologic Treatment for Prolactinoma or Idiopathic Hyperprolactinemia

• First-line therapy: Dopamine agonists 1, 2, 4

  • Cabergoline: More effective and better tolerated than bromocriptine 4

    • Initial dose: 0.25 mg twice weekly
    • Titrate by 0.25 mg twice weekly at 4-week intervals
    • Maximum dose: typically up to 1 mg twice weekly 1

  • Bromocriptine: Alternative option, especially for women planning pregnancy 2

    • More data available on safety during pregnancy
    • More frequent dosing required (usually twice daily)
    • Higher incidence of side effects

3. Monitoring

• Prolactin levels should be checked regularly to assess treatment response
• For patients with prolactinoma:
  • Follow-up MRI at 3-6 months after initiating treatment
  • Regular monitoring of visual fields if macroadenoma
  • Echocardiography monitoring for patients on cabergoline:
    • Every 5 years if dose ≤2 mg/week
    • Yearly if dose >2 mg/week 1

4. Surgical Consideration

• Reserved for patients who are:
  • Resistant to dopamine agonist therapy
  • Intolerant to medical therapy
  • Have rapidly progressive visual field loss
  • Express preference for definitive treatment 1

Important Considerations and Pitfalls

• Medication-induced hyperprolactinemia: Always review all medications before proceeding to expensive imaging studies 3

• Macroprolactinemia: Some patients may have elevated levels of less biologically active forms of prolactin without clinical symptoms 5

• Visual field monitoring: Essential in patients with macroadenomas due to risk of chiasmal compression 1, 6

• Pregnancy considerations: Bromocriptine mesylate should be discontinued when pregnancy is diagnosed unless there's risk of tumor expansion 6

• Cardiac monitoring: Patients on cabergoline require echocardiography monitoring due to potential cardiac valve effects, especially at higher doses 1

• Side effects of dopamine agonists: May include nausea, dizziness, headache, and rarely impulse control disorders (gambling, hypersexuality) 6