What is the next step for a patient with hyperprolactinemia, should I recheck the prolactin level or proceed with a Magnetic Resonance Imaging (MRI) of the pituitary gland?

From the Guidelines

For a patient with hyperprolactinemia, I strongly recommend rechecking the prolactin level before proceeding to MRI imaging, as this approach ensures accurate diagnosis and appropriate resource utilization. The recheck is crucial because prolactin levels can fluctuate due to various factors, including stress, medications, hypothyroidism, renal failure, or even the stress of venipuncture itself, as noted in the consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence 1.

Key Considerations for Rechecking Prolactin Levels

• Prolactin levels can be affected by stress and prolactin pulsatility, making serial measurements over time necessary to exclude these effects, as suggested by the guideline 1.
• A single prolactin measurement taken at any time of the day is sufficient to assess hyperprolactinaemia, but sampling can be repeated on a different day with two or three samples at 20–60 min intervals to differentiate stress-related hyperprolactinaemia from organic disease 1.
• The diagnosis of hyperprolactinaemia requires age-specific and sex-specific prolactin reference ranges and the exclusion of confounding conditions, such as hypothyroidism, renal and/or hepatic impairment, and use of medications that cause hyperprolactinaemia, as emphasized in the guideline 1.

Next Steps After Rechecking Prolactin Levels

• If the elevated prolactin level is confirmed on repeat testing, then an MRI of the pituitary gland with contrast is the appropriate next step to identify potential causes such as prolactinomas, other pituitary lesions, or stalk compression.
• The MRI will help guide treatment decisions, which may include dopamine agonists like cabergoline as first-line therapy for prolactinoma, as recommended in the consensus guideline 1.

Importance of Accurate Diagnosis

• Accurate diagnosis is crucial for guiding treatment decisions and improving patient outcomes, as noted in the guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence 1.
• A sequential approach, starting with rechecking prolactin levels and followed by MRI imaging if necessary, ensures the most accurate diagnosis and appropriate treatment for patients with hyperprolactinemia.

From the FDA Drug Label

Since pregnancy is often the therapeutic objective in many hyperprolactinemic patients presenting with amenorrhea/galactorrhea and hypogonadism (infertility), a careful assessment of the pituitary is essential to detect the presence of a prolactin‑secreting adenoma Patients with rapidly progressive visual field loss should be evaluated by a neurosurgeon to help decide on the most appropriate therapy A complete evaluation of the pituitary is indicated before treatment with bromocriptine mesylate.

The next step for a patient with hyperprolactinemia is to have a careful assessment of the pituitary to detect the presence of a prolactin-secreting adenoma.

• If the patient has rapidly progressive visual field loss, they should be evaluated by a neurosurgeon to decide on the most appropriate therapy.
• A complete evaluation of the pituitary is necessary before starting treatment. There is no direct information in the provided drug labels that suggests when to recheck the prolactin level or proceed with an MRI of the pituitary gland. 2, 2, 3

From the Research

Next Steps for Hyperprolactinemia Diagnosis

The next step for a patient with hyperprolactinemia involves a series of diagnostic evaluations to determine the underlying cause of the condition.

• The first step is to exclude other causes of hyperprolactinemia, such as pregnancy, primary hypothyroidism, numerous medications, and miscellaneous causes 4.
• Once these causes are ruled out, a head scan, preferably an MRI, is performed to exclude a "pseudoprolactinoma" which would require surgery 4.
• According to a study published in 2007, hypothalamic-pituitary MRI is the reference morphological examination for diagnosing hyperprolactinemia, especially when the increase in prolactin level is marked 5.
• However, in cases of moderate hyperprolactinemia, it is essential to follow a rational diagnostic plan, including history-taking, investigation for endocrine diseases, and confirmation of hyperprolactinemia by a second assay before proceeding with imaging 5.
• Another study published in 2002 suggests that patient samples showing hyperprolactinemia should be first tested for macroprolactin before the patient is submitted to imaging studies, as the presence of macroprolactinemia does not exclude the possibility of a pituitary adenoma 6.
• In cases where the etiology of hyperprolactinemia is not clearly due to medication, an MRI of the pituitary gland is indicated, as it facilitated the diagnosis of pituitary microadenoma in a case report published in 2017 7.
• A study published in 1994 also recommends that marginal elevations in serum prolactin concentration require magnetic resonance imaging and evaluation for acromegaly 8.

Diagnostic Evaluation

The diagnostic evaluation for hyperprolactinemia should include:

• Exclusion of other causes of hyperprolactinemia
• MRI of the pituitary gland to exclude a "pseudoprolactinoma"
• Testing for macroprolactin
• Evaluation for acromegaly in cases of marginal elevations in serum prolactin concentration
• A rational diagnostic plan, including history-taking and investigation for endocrine diseases, in cases of moderate hyperprolactinemia 5.

Imaging Studies

Imaging studies, such as MRI, are essential in diagnosing hyperprolactinemia, especially in cases where the etiology is not clearly due to medication 7.

• MRI of the pituitary gland can help diagnose pituitary microadenoma and other pituitary tumors 4, 5, 7.
• The study published in 2002 suggests that imaging studies should be ordered in patients with macroprolactinemia when indicated by clinically relevant features 6.