Endocrine Abstracts

Background: Pituitary stalk interruption syndrome (PSIS) is a rare congenital condition characterised by the triad of thin or absent pituitary stalk, hypoplasia of the adenohypophysis, and ectopic neurohypophysis. PSIS has multifactorial aetiology with highly heterogenous clinical manifestations, usually diagnosed in early infancy or childhood. There have been previous reports of untreated panhypopituitarism diagnosed in adulthood, indicating preservation of some pituitary function. Nearly all patients had normal posterior pituitary function. It is difficult to predict the onset of hormonal crisis, making routine surveillance of critical importance. We present an unusual case of a 31-year-old male who has been off hormonal supplementation for at least a decade with an acute hypoadrenal crisis. Our case highlights the challenges in transition of care from paediatric to adult services and the importance of long-term follow-up of PSIS patients.

Clinical Case: Our patient presented following an acute episode of collapse in the context of a recent viral infection, with profoundly hyponatremia (98 mmol/l) and seizure. Congenital hypopituitarism was diagnosed at 10 days of age and managed with hydrocortisone, thyroxine and growth hormone replacements under paediatric endocrinology care, reaching predicted height of 170 cm . After a brief period of testosterone therapy at age 18, he was lost to follow-up and had been on no replacement between age 18–30. He was able to maintain a physically demanding job without any significant adrenal crises or hospitalisation until his recent presentation. Physical examination revealed no dysmorphic features. His biochemistry during admission was consistent with central hypothyroidism (TSH 0.81 mIU/l, FT4 7 pmol/l, FT3<1.5 pmol/l) with non-detectable growth hormone and gonadotropins. Cortisol was measured post stress doses of hydrocortisone and ACTH was 1.9 pmol/l. Prolactin was 300 mIU/l. MRI pituitary confirmed extremely thin stalk with small residual pituitary gland, an area of T1 brightness representing probable ectopic pituitary tissue, and posterior bright spot was not present. He was recommenced on glucocorticoid and thyroxine replacement with normalisation of serum sodium, and will continue to follow up with an adult service.

Conclusion: The present case aims to raise awareness of PSIS, a rare condition predominantly diagnosed in the paediatric population with lasting impact into adulthood. It should be emphasised to patients as they enter adolescence the importance of ongoing hormone replacement, and active efforts should be made to facilitate transition of care to an adult service along with medical alerts, sick day management and family awareness of the condition.