SUN-427 Hypopituitarism as a Rare Manifestation in a Patient with Neurosarcoidosis

Abstract

Introduction: Sarcoidosis is a systemic disease of unknown cause that is characterised by the formation of immune granulomas in various organs, mainly the lungs and lymphatic system. 5-10% of patients with sarcoidosis present with neurological involvement [1,2]. Neuroendocrine dysfunction is uncommon with hypothalamic-pituitary dysfunction occurring in 2-8% of patients with neurosarcoidosis [3]. Clinical case: A 47 year old caucasian male presented with a ten month history of severe fatigue, weight gain, loss of libido, erectile dysfunction and polyuria. Past medical history was significant for sarcoidosis for which he had been lost to follow up for many years. On examination, body mass index was 31.1kg/m2 with central obesity and loss of secondary sexual characteristics and gynaecomastia were noted. Initial endocrine investigations confirmed central hypothyroidism ((TSH: 1.87mIU/L (0.35-4.94), fT4: 8.6 Pmol/L (9.0-20.0)) and hypogonadotropic hypogondism ((FSH: 1.5 IU/L (1.4-10.8), LH: <0.5 IU/L (1.4-6.5), AM Testosterone: 0.7nmol/L (7.1-407)). IGF-1 and prolactin concentrations were normal. Short synacthen® test was abnormal with peak cortisol at 60 mins of 445 nmol/L and ACTH 15ng/L (7-63). Water deprivation testing confirmed partial Diabetes Insipidus. Chest Xray showed mediastinal and bihilar lymphadenopathy consistent with sarcoidosis. MRI brain and pituitary with gadolinium revealed a normal sized pituitary gland, pituitary infundibulum at the upper limit of normal thickness (3mm) and signal abnormality of the periaqueductal grey matter and tectal plate which demonstrated enhancement following contrast administration, and the presence of abnormal enhancement of the optic chiasm/hypothalamus, consistent with neurosarcoidosis. A diagnosis of hypopituitarism secondary to neurosarcoidosis was made. The patient was commenced on steroid and testosterone replacement with the later addition of levothyroxine and ddAVP, with marked improvement in symptoms. He required a Multidisciplinary team approach with respiratory and neurology input. Conclusion: This case illustrates a rare presentation of hypopituitarism secondary to neurosarcoidosis in a young patient lost to medical care. It is important that patients with sarcoidosis have long-term follow up with consideration given to rare endocrine manifestations in the appropriate clinical setting.