Endocrine Abstracts

Case history: A 19 year old lady presented with amenorrhoea, fatigue and headaches. She had normal pubertal growth spurt with an appropriate height for mid-parental height. Her menarche was at age 17, another bleed at 18 but amenorrhoeic since. There was right sided galactorrhoea only on expression. In her teens she had an eating disorder, periods of self-harm and low mood. No treatment except for St. John’s Wort occasionally. No visual disturbance was present.

Investigations: Biochemical investigations and pituitary MRI.

Results and treatment: Hyperprolactinaemia (12 225 munits/l), IGF1 24 pmol/l, LH 2.7 units/l, FSH 4.3 units/l, oestradiol 67 pmol/l, testosterone 2.5 nmol/l, cortisol 653 nmol/l, free T₄ 13.2 pmol/l, corrected calcium 2.23 mmol/l.

Pituitary MRI showed 17×15×17 mm left sided partially cystic macroadenoma within the fossa.

Patient was started on treatment with cabergoline, titrated up to 0.25 mg three times a week. Her prolactin level on this treatment was 3017 munits/l. However cabergoline had a mildly negative effect on her mood and therefore treatment was stopped. A week after her prolactin level was 6156 munits/l.

We postulated that the mood lowering effect of cabergoline might be dose related and therefore restarted treatment with cabergoline 0.25 mg every 2 weeks, with an intention very gradually to increase the dose and monitor any adverse symptoms. There was a ceiling of cabergoline dose above which she developed adverse symptoms, but the maximum tolerated dose was continued prior to pituitary surgery in order to try and optimise the surgical target. Transphenoidal surgery resulted in mild compensating transient diabetes insipidus, managed conservatively and resolved spontaneously. Hyponatremia followed diabetes insipidus, which resolved with fluid restriction. ACTH-cortisol axis following surgery was intact and prolactin level was undetectable. There was no cerebrospinal fluid leak. Patient had continuous nose bleed from right nostril, for which she received ENT review, nasal packing for 24 h, tranexamic acid, and amoxicillin and clavulanate, which led to resolution.

A year from surgery patient is feeling slightly tired but is otherwise well, only occasional occipital headaches relieved with simple analgesics. Amenorrhoea persists. Prolactin 11 munits/l, LH 12 units/l, FSH 6.3 units/l, TSH 2.53 munit/l, free T₄ 17.7 pmol/l, random cortisol 326 nmol/l, and sodium 141 mmol/l.

Conclusions and points for discussion: We describe a case of macroprolactinoma discovered following investigation of amenorrhoea, initially treated with cabergoline, stopped due to adverse effects, and then with transphenoidal surgery after medical preparation with the maximum tolerated dose of cabergoline to optimise the surgical target. Ongoing management questions include whether persisting amenorrhoea requires further investigation and whether macroadenoma discovered at a young age requires any genetic testing. The effects of cabergoline on mood in patients with a history of low mood and its dose-dependent nature merits further discussion.