Endocrine Abstracts

Case History: A 64-year-old gentleman presented to the emergency department with acute onset dizziness, nausea, vomiting and difficulty in standing. Although his symptoms lasted only for a few hours, his neurological examination was unremarkable. His past medical history included atrial fibrillation, factor V Leiden deficiency and previous left lower limb DVT. He was not on any medications that can cause hyperprolactinaemia. The stroke team who reviewed him initially diagnosed it as an acute episode of vertigo of a non-vascular aetiology and requested initial CT head that did not show any acute intracranial pathology but it showed a bulky pituitary gland. He was reviewed by the endocrine consultant in the medical take and on further questioning, he denied any history of galactorrhoea, headaches, visual disturbances or symptoms of hypogonadism.

Investigations: Formal Goldmann visual field testing showed no significant abnormality; Pituitary profile showed a raised Prolactin 24886 mIU/L (56-278), random cortisol 284 nmol/l, FSH 4.4 IU/L (1.5-18), LH 2.5IU/L (1.5-9.3), testosterone 3.4 nmol/l (8.4-27.4), TSH 2.82mIU/L (0.3-4.8), IGF1 17.5nmol/l. MRI Pituitary confirmed a pituitary macroadenoma measuring 12mm x 12mm x 21mm partially obscuring suprasellar cistern and showing a protrusion into the left carotid siphon with no optic chiasm compression or no cavernous sinus invasion.

Results and treatment: He was commenced on cabergoline 500 mg once weekly and then discharged. Interestingly his prolactin levels dropped to 273 mIU/L within 8 weeks of treatment with cabergoline. Pituitary Multidisciplinary team meeting advised continuation of dopamine agonist therapy and repeating MRI Pituitary in 6 months.

Conclusions and points for discussion: The novelty in this case is the unusual presentation of an incidental finding of a pituitary macroadenoma in an acute medical take with significant hyperprolactinaemia in a patient who did not display any symptomatology associated with this degree of disease reported in the literature. It was just by chance that his CT scan was reviewed by an endocrinologist earlier on during the admission process and baseline pituitary function was requested. Hence the diagnosis was picked up which could have been easily missed in a busy medical take. The rate of resolution of hyperprolactinaemia on Cabergoline within the first few weeks of treatment is interesting in our case, although there have been similar case reports but with CSF rhinorrhoea following treatment of giant invasive macroprolactinomas, unlike our case who remained well and carefully monitored.