Delayed presentation of late onset CSF rhinorrhoea following dopamine agonist therapy for giant prolactinoma

J. Prague; O. Mustafa; C. Ward; C. Manu; N. Thomas; T. Hampton; A. King; J. Kumar; J. Gilbert; B. Whitelaw

Background: CSF rhinorrhoea is a rare but recognised complication of dopamine agonist therapy for macroprolactinoma. In the majority of cases, onset of CSF rhinorrhoea is within 4 months of commencing therapy.

Case report: A 23-year-old man presented to the Emergency Department in April 2010 with acute weakness in his left arm and leg associated with intermittent headaches. Examination revealed mild right-sided ptosis and inadequate androgenisation. Visual fields were full to confrontation.

MRI pituitary demonstrated a 5 cm lobular/cystic mass invading the right cavernous sinus, displacing and compressing the midbrain, with destruction of the bony sella. Serum prolactin was >150 000 mIU/l.

Cabergoline was commenced (initially 250 μg twice/week). Neurological symptoms resolved with dramatic reduction in tumour size. Serum testosterone levels normalised. Prolactin level plateaued at 20 000 mIU/l despite repeated increments in the dose of cabergoline to 500 μg three times/week over the course of 12 months. There was still significant residual sellar and right parasellar tumour. Consequently, the cabergoline dose was increased to 500 μg/day following which he developed continuous daily rhinorrhoea (May 2011).

The patient presented to his general practitioner who referred him to an otolaryngology clinic. When next seen in the routine regional endocrine clinic (November 2011) he was admitted for urgent endoscopic transnasal transphenoidal repair of CSF leak. CT pituitary confirmed the likely site of the leak was in the left basisphenoid where there was marked thinning of the bone. Preoperative serum prolactin was 3240 mIU/l on cabergoline 500 μg/day. Histology confirmed a prolactinoma with proliferation index of 2%.

Discussion: In this case, CSF rhinorrhoea occurred 13 months after initiation of cabergoline suggesting a need for vigilance throughout therapy.

There was significant delay before this complication was brought to the attention of the regional pituitary team. There is a need for patients and healthcare professionals to be educated about early recognition and management of this complication.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.

Endocrine Abstracts

P345