Background: Hyperprolactinemia can be caused by medications, primarily antipsychotics, or
by anterior pituitary tumors. The consequences of hyperprolactinemia including gynecomastia, galactorrhea,
and sexual dysfunction are very disturbing for males and females. It is sometimes difficult to differentiate
the etiology of hyperprolactinemia from a clinical perspective.
Objective: Identification of the etiology of hyperprolactinemia requires a careful review of the causes
and appropriate work-up.
Methods: A 55-year-old African American male with extensive psychiatric history and non-adherence
to treatment was admitted from nursing home for aggression and psychotic symptoms. The patient was
noted to have mild bilateral breast enlargement about ten days after hospitalization. Prolactin level done
on August 26, 2014 was 93.8 ng/mL, and on September 5, 2014 was 112 ng/mL. The patient’s medications
included haloperidol decanoate 150 mg q28d, haloperidol 10 mg po bid and benztropine 0.5 mg po
bid. He did not have any other clinical signs or symptoms of hyperprolactinemia. He was also seen by
an endocrinologist. MRI of the pituitary gland done on September 3, 2014, showed a 2.4 mm pituitary
microadenoma. Bromocriptine was started at 1.25 mg qhs and titrated to 2.5 mg bid.
Results: Prolactin level dropped from 112 ng/mL on September 5, 2014 to 99 ng/mL on September 9,
2014, 61.2 ng/mLon September 23, 2014 and 3.0 ng/mL on February 9, 2015.
Conclusion: Diagnosis and etiology of hyperprolactinemia were complicated by the minimal nature of
clinical symptoms, the type of antipsychotic agent and the prolactin level. The MRI facilitated the diagnosis
of pituitary microadenoma and further treatment option with bromocriptine. MRI of the pituitary
is indicated for patients with hyperprolactinemia where the etiology is not clearly due to medication.