A 27-year-old woman comes to the office for evaluation of infertility. The patient and her husband have been trying to conceive for the past 2 years but have been unsuccessful. Her husband recently underwent infertility evaluation and was found to have no abnormalities. The patient's menses began at age 13, and her menstrual cycles were regular until the last few years, when they began occurring at intervals of 3-4 months. She has occasional headaches but no other symptoms. The patient has no prior medical conditions and takes no medications. On physical examination, the patient appears normal and has well-developed secondary sexual characteristics. Cardiopulmonary and abdominal examinations are normal. Pelvic examination reveals no adnexal masses. Neurological examination shows diminished vision in the bilateral temporal visual fields. Examination of the other cranial nerves is normal and there is no focal weakness or sensory loss. An abnormality originating in which of the following is the most likely cause of this patient's current condition?

Question

A 27-year-old woman comes to the office for evaluation of infertility.  The patient and her husband have been trying to conceive for the past 2 years but have been unsuccessful.  Her husband recently underwent infertility evaluation and was found to have no abnormalities.  The patient's menses began at age 13, and her menstrual cycles were regular until the last few years, when they began occurring at intervals of 3-4 months.  She has occasional headaches but no other symptoms.  The patient has no prior medical conditions and takes no medications.  On physical examination, the patient appears normal and has well-developed secondary sexual characteristics.  Cardiopulmonary and abdominal examinations are normal.  Pelvic examination reveals no adnexal masses.  Neurological examination shows diminished vision in the bilateral temporal visual fields.  Examination of the other cranial nerves is normal and there is no focal weakness or sensory loss.  An abnormality originating in which of the following is the most likely cause of this patient's current condition?

Quizplus · Accepted Answer

11ec160b_3918_2e88_9249_437dd283f7fc_MD0001_00 This patient's symptoms are concerning for a pituitary tumor. Large pituitary tumors can cause headaches due to mass effect, and compression of the optic chiasm by suprasellar extension of the tumor can lead to bitemporal hemianopsia. The most common type of pituitary adenoma is a prolactinoma. Prolactin is a peptide hormone secreted from lactotrophs of the pituitary gland whose primary physiologic action is maintenance of lactation in postpartum women. Hyperprolactinemia also suppresses GnRH production in the hypothalamus, leading to oligomenorrhea/amenorrhea and infertility. Suppression of ovulation is also seen as a physiologic effect of breastfeeding, which supports elevated prolactin levels for 6 months or more postpartum. (Choice A) Kallmann syndrome is a disorder involving the GnRH-producing neurons in the hypothalamus. In addition to decreased sense of smell (anosmia/hyposomia), this condition causes hypogonadotropic hypogonadism and presents with short stature and delayed puberty (primary amenorrhea). This patient has secondary amenorrhea (ie, normal initial onset of puberty followed by menstrual dysregulation), and her bilateral temporal visual deficits are more suggestive of a pituitary rather than hypothalamic lesion. (Choice B) Ovarian granulosa cells produce estrogen, progesterone, and inhibin. Loss of these cells (eg, due to autoimmune disorder) can lead to primary ovarian insufficiency and present with infertility and secondary amenorrhea. However, patients often have hypoestrogenic symptoms (eg, hot flashes), and this disorder would not cause visual field defects. (Choice C) Ovarian theca cells produce androgens, which provide the substrate for subsequent synthesis of estrogens. Amenorrhea and infertility related to hyperactivity of these cells are typically associated with signs of hyperandrogenism (eg, hirsutism). (Choice E) Unlike most pituitary hormones, which are under positive regulation by the hypothalamus, prolactin is primarily under negative regulation by hypothalamic dopaminergic neurons via the pituitary stalk. Because of this, any pituitary tumor of significant size that disrupts these dopaminergic pathways can cause moderate hyperprolactinemia. However, somatotroph adenomas typically cause acromegaly, with prognathism and bony enlargement of the hands and feet. Educational objective: Prolactinomas are the most common pituitary adenoma and can cause galactorrhea, menstrual irregularities, and infertility in premenopausal women. Large pituitary adenomas can cause headaches from mass effect and bitemporal hemianopsia from compression of the optic chiasm. __________ References: Progress in the diagnosis and classification of pituitary adenomas. (http://www.ncbi.nlm.nih.gov/pubmed/26124750)

A 27-Year-Old Woman Comes to the Office for Evaluation of Infertility