Endocrine Abstracts

Case history: The patient was a 17-year old lady who was referred to us by her primary care provider for hyperprolactinaemia and primary amenorrhoea. She was of short stature (0.4th centile for height and minus 2 centile spaces of the mid-parental height) and in the 9th–25th centile range for weight. There was no history of galactorrhoea. Her breast development was Tanner stage 3–4, and pubic hair 2–3, with no axillary hair. There was no evidence of any intellectual impairment. There was a family history of hypothyroidism in her maternal aunt and grandfather.

Investigations: FT4 <3 pmol/l, TSH >100 mU/l, Prolactin 2069 mIU/l (Monomeric Prolactin 1635 mIU/l), LH < 1 IU/l, FSH 4.5 IU/l, Oestradiol <98 pmol/l, SHBG 57 nmol/l, IGF-1 23.8 nmol/l, AM Cortisol 436 nmol/l and positive coeliac screen. The calculated bone age was 13.2 years. MRI pituitary and the ultrasound of her uterus and ovaries were normal.

Results and treatment: After initiation of thyroid hormone replacement, serum TSH and prolactin levels fell progressively into the normal range. Along with these changes, the patient noted a return of normal menstrual function.

Conclusion and points for discussion: Hyperprolactinemia is a common cause of secondary amenorrhoea, but an uncommon cause of primary amenorrhoea. The presentation is similar to hypothalamic amenorrhoea except for the additional finding of galactorrhoea in some patients. The combination of amenorrhea and hyperprolactinemia in a young woman usually suggests a prolactin-secreting adenoma of the anterior pituitary gland. Primary thyroid failure may also be associated with hyperprolactinemia, galactorrhea and suprasellar enlargement of the pituitary (pseudoprolactinoma).