Endocrine Abstracts

Introduction: Dopamine agonists (DA) are treatment of choice in Prolactinoma. We report a patient manifesting symptoms and signs of PD following temporary cessation of Cabergoline for Macroprolactinoma.

Case: A 68-year-old gentleman was referred to Endocrinology following an incidental finding of 1.7 x 1.7 x 2 cm mass in pituitary fossa on CT Head. Patient was asymptomatic, denied headache or visual disturbances and clinical examination was unremarkable. Biochemistry demonstrated elevated Prolactin (PRL) of 42460 mIU/l (range 73-403) with rest of pituitary function being normal. Cabergoline 500ug twice weekly was started for Macroprolactinoma. His PRL level came down to 330 mIU/l. However, he developed symptoms of anxiety which failed to respond to standard treatment. Cabergoline was considered the culprit agent; it was tapered and stopped. He then developed visual hallucinations, unsteady gait, difficulty initiating movement and legs feeling like “lead” and “frozen”. He was referred to Neurology and diagnosed with Idiopathic PD and commenced on Levodopa. His neurological symptoms improved but PRL continued to rise. Bromocriptine was added and was well tolerated and resulted in biochemical remission and shrinkage of adenoma on CT.

Discussion: This case highlights an interesting and unique phenomenon of unmasking symptoms of PD following withdrawal of DA therapy which has not been previously documented in literature. This is different from the established entity of DA withdrawal syndrome seen in patients with diagnosed PD following DA withdrawal. Cabergoline either as monotherapy or in combination with Levodopa is effective for managing motor symptoms of PD. It is probable that the neurological symptoms that appeared after Cabergoline cessation in our patient are either due to unmasking of preexisting PD or a coincidental occurrence, but it is important for clinicians to be aware of this possibility.