Endocrine Abstracts

A 36 year old lady presented to the endocrine clinic with a 4 month history of secondary infertility, amenorrhea, galactorrhoea and headaches. She had stopped breast-feeding her 5th child 18 months previously and was not taking any antidopaminergic drugs. She had a normal neuro-ophthalmic examination, including full visual fields to confrontation with a red pin. Her prolactin was elevated at 5690 mU/l and MRI pituitary confirmed a 17 mm partially cystic macroadenoma which was approaching, but not contacting the optic chiasm.

She was commenced on cabergoline 0.25 mg twice weekly, but was unable to tolerate this due to nausea and vomiting. She was therefore changed to bromocriptine 1.25 mg od, which resulted in restoration of menses. She returned to clinic 7 weeks pregnant and was advised to remain on bromocriptine throughout her pregnancy. She discontinued her bromocriptine at 13 weeks gestation due to nausea, vomiting and dizziness and failed to attend subsequent appointments. She had a normal vaginal delivery following induction at 38 weeks gestation.

She represented to the endocrinology clinic 5 months post-partum with persistent galactorrhoea and amenorrhoea having discontinued breast-feeding 2 months earlier. Repeat MR imaging showed the pituitary adenoma to be 13 mm. She was commenced on quinagolide 75 μg od and subsequently conceived and stopped her medication. She was admitted to hospital at 33 weeks gestation with worsening headache and a non-contrast pituitary MRI showed growth of the adenoma to 18 mm, touching the left optic nerve. Visual fields remained intact. She was commenced on bromocriptine 1.25 mg od and had an elective caesarean section and tubal ligation at full term with hydrocortisone cover.

Quinagolide was re-commenced post-partum, but was discontinued due to nausea and vomiting. She was therefore referred for trans-sphenoidal surgery. She underwent an uncomplicated resection of the lactotroph macroadenoma, resulting in normalisation of prolactin post-op and preservation of anterior pituitary function.

This case highlights the potential difficulties in treating pituitary lactotroph adenomas in cases of dopamine agonist intolerance.