What is the workup for hyperprolactinemia?

From the Guidelines

The workup for hyperprolactinemia should begin with a single blood sample collected at any time of day to measure prolactin levels, as recommended by the most recent guidelines 1.

Initial Evaluation

The initial evaluation of hyperprolactinemia involves confirming elevated prolactin levels, which can fluctuate due to stress, exercise, or meals.

• A thorough history and physical examination should be conducted, focusing on symptoms like galactorrhea, menstrual irregularities, infertility, decreased libido, and erectile dysfunction.
• Medication review is essential as drugs like antipsychotics, metoclopramide, and certain antidepressants can cause hyperprolactinemia.

Laboratory Tests

Laboratory tests should include:

• Thyroid function tests (hypothyroidism can elevate prolactin) 1
• Renal and liver function tests
• Pregnancy testing in women of reproductive age
• Assessment of other pituitary hormones if a macroadenoma is present

Imaging Studies

Magnetic resonance imaging (MRI) of the pituitary gland is crucial to identify prolactinomas or other sellar masses.

• For macroprolactinemia, polyethylene glycol precipitation testing can be performed 1.
• Serial dilutions of serum for prolactin measurement should be performed in patients with large pituitary lesions and normal or mildly elevated prolactin levels 1.

Treatment

Treatment strategies may include dopamine agonists like cabergoline (starting at 0.25mg twice weekly) or bromocriptine (starting at 1.25-2.5mg daily) for prolactinomas, as recommended by the most recent guidelines 1.

• Cabergoline is the dopamine agonist of choice given its superior effectiveness and lower adverse effect profile.
• If the serum level of prolactin has been normalized for at least 2 years on medical therapy and there is no visible residual prolactinoma on MRI, consider gradual cabergoline dose reduction to maintain normoprolactinaemia and eventual treatment discontinuation, with continued serum prolactin monitoring for at least 2 more years 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Workup for Hyperprolactinemia

The workup for hyperprolactinemia involves several steps to determine the cause of elevated prolactin levels.

• Initial evaluation:
  • Measure serum prolactin levels, which can be affected by various factors such as pregnancy, primary hypothyroidism, and certain medications 2.
  • Repeat the measurement in the morning with the patient in a fasting state to confirm the diagnosis.
• Medical history and laboratory tests:
  • Eliminate common physiologic and pharmacologic causes of hyperprolactinemia, such as pregnancy and primary hypothyroidism 2.
  • Check for other conditions that may cause hyperprolactinemia, such as hypothyroidism, which can be associated with hyperplasia of the TSH and prolactin-producing cells 3.
• Radiologic imaging:
  • Perform imaging of the sella turcica to establish whether a prolactin-secreting pituitary adenoma or other lesion is present 2.
  • Use techniques such as magnetic resonance imaging (MRI) to visualize the pituitary gland and detect any abnormalities.
• Additional tests:
  • Measure free thyroxine (F-T4) and thyroid-stimulating hormone (TSH) levels to rule out primary hypothyroidism 3.
  • Consider other tests, such as polyethylene glycol (PEG) precipitation, to identify macroprolactinemia, a common cause of interference in prolactin assays 4.

Importance of Accurate Diagnosis

Accurate diagnosis of hyperprolactinemia is crucial to determine the underlying cause and develop an effective treatment plan.

• Incorrect diagnosis can lead to unnecessary investigations and treatment, highlighting the need for careful evaluation and consideration of all possible causes 4.
• A thorough workup, including medical history, laboratory tests, and radiologic imaging, can help identify the underlying cause of hyperprolactinemia and guide treatment decisions 2.