Endocrine Abstracts

A 30year old Afrocarribean man with sarcoidosis presented with unexplained weight gain from 98kg to 112kg over 6 months. He had previously documented bilateral hilar lymphadenopathy, erythema nodosum, arthralgia, a positive gallium scan and a raised serum angiotensin converting enzyme(ACE).

He also described hypersomnolence, impaired concentration, decreased libido and intermittent headaches with no other neuro-psychiatric symptoms. He was not on any regular medication.

Clinical examination revealed central obesity, acanthosis nigricans, non-pigmented striae, mild proximal muscle weakness and a normal blood pressure. There was reduced axillary/pubic hair and testes of 9ml bilaterally. Visual fields were normal to red pin.

Baseline tests; basic biochemistry and haematology was normal. Serum ACE was elevated at 118 IU/L; TSH 0.92 mIU/L FT4 11.2 pmol/L; LH 0.1 IU/L FSH 0.5 IU/L Testosterone 0.2 nmol/L; Cortisol 900nmol/L and Prolactin was 418 mIU/L. A GnRh test revealed a flat gonadotrophin response. A low dose dexamethasone suppression test and a TRH test were normal. There was no evidence of diabetes insipidus.

An MRI san of the brain revealed a high signal lesion of irregular morphology occupying the hypothalamic area and extending down towards the pituitary fossa.

Neurosarcoidosis was considered the most likely diagnosis - with evidence of hypothalamo-pituitary dysfunction. Therapy was initiated with 5 days of pulsed methylprednisolone followed by maintenance therapy - prednisolone 40mg per day, methotrexate 7.5mg weekly alendronate, and calcichew D3. Testosterone replacement therapy was provided. Diabetes mellitus later developed for which metformin was required.After 2 months of therapy, an MRI scan showed almost complete resolution of the hypothalamic high signal lesion.

Neurological involvement in sarcoidosis commonly causes cranial nerve and/or meningeal abnormalities. The hypothalamus is the most frequently involved endocrine gland. In this case, both appetite dysregulation and anterior pituitary dysfunction necessitated potent disease modifying treatment. Inducing weight loss remains a challenge.