Endocrine Abstracts (2016) 45 OC1.1 | DOI: 10.1530/endoabs.45.OC1.1

Pan hypopituitarism - Is it secondary to brain tumour and its treatment?

Ved Bhushan Arya & Helen Spoudeas

Great Ormond Street Hospital, London, UK.

A 10-year old boy presented with 12-months history of headache, vomiting, declining school performance and change in behavior. There was no visual disturbance. Neurological examination was normal. Weight and height were between 50th−75th centile. CT head showed a large, partly calcified mass in the sellar region with acute hydrocephalus. Dexamethasone was immediately commenced and care was transferred to the neurosurgical centre.

MRI brain confirmed partly cystic, partly solid intra-and supra-sellar mass with displacement of anterior visual pathway and obstructive hydrocephalus. Pre-operative endocrine investigations showed normal prolactin, normal free T4 with low TSH, normal IGF1/IGFBP3 and normal serum sodium and osmolality. Serum cortisol was low (34 nmol/l), however this was measured post-commencement of dexamethasone.

Initial surgical management involved endoscopic cyst-aspiration and Ommaya reservoir insertion. Dexamethasone was stopped post-surgery and early morning cortisol after 48 hours was satisfactory (364 nmol/l). Subsequently tumor excision was undertaken (histology: adamantinomatous craniopharyngioma). Post-surgery, triphasic response (diabetes insipidus - syndrome of inappropriate ADH secretion - diabetes insipidus) was observed. Management involved intense monitoring of fluid balance, serum and urine electrolytes/osmolality and stat DDAVP doses until permanent diabetes insipidus was clearly established. Perioperative hydrocortisone cover was provided. Measurement of serum cortisol (pre-hydrocortisone dose) at 7 am, 8 am and 9 am (37, 41 and 41 nmol/l) indicated ACTH deficiency. Low fT4 (5.4 pmol/l) and low TSH (0.7 mU/l) post-operatively suggested TSH deficiency.

At discharge, the proband was on DDAVP, Levothyroxine and Hydrocortisone. Post-discharge, investigation with combined pituitary function testing (Growth Hormone [GH] stimulation, LHRH and TRH testing) showed absent GH, LH/FSH and TSH response, confirming GH deficiency, gonadotropin and TSH deficiency. GH treatment was commenced. In view of near-complete tumor resection, multi-disciplinary supra-regional discussion forum decided against radiotherapy treatment. Recurrence of craniopharyngioma was noticed 1-year after surgery, for which a second resection was undertaken after multi-disciplinary discussion.

Conclusions: Pituitary reserve should be assessed, if possible, before surgery to ascertain whether the deficit is secondary to tumor or its treatment. Anticipation of triphasic response (DI-SIADH-DI) and appropriate management is critical. Recurrence rate of craniopharyngioma is high without adjuvant radiotherapy. The difficult decisions regarding optimal treatment strategy are best taken in a supra-regional/national forum.

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