Endocrine Abstracts

Disorders of sodium metabolism in sarcoidosis are predominated by diabetes insipidus; SIADH is extremely rare, restricted to sporadic case reports. We present the case of a 68 year old South Asian female presenting with a 3 year history of chronic, mild hyponatraemia, which was asymptomatic apart from mild lightheadedness. She had a history of stable sarcoidosis that was not requiring treatment, based on lung pathology. Despite fluid restriction, serum sodium remained around 128 mmol/l; serum osmolality was 263 mOsm/kg, urine osmolality 296 mOsm/kg, and urine sodium 76 mmol/l. TSH was normal, 3.52 mIU/l. A Short synacthen test was normal: baseline serum cortisol of 497 nmol/l, rising at 30 mins to 809 and at 60 mins to 1002. IGF-1 and HbA1c were normal. Serum ACE was raised, 82U/L.A CT Chest/Abdomen/Pelvis revealed two calcified paratracheal lymph nodes and stable apical thickening in both lungs, with slightly more marked subpleural reticulation in right upper lobe of lung. An MRI scan of the brain showed no gross pituitary pathology. The patient was managed with oral slow-sodium 2 tabs bd and furosemide 20 mg od. In light of the hyponatremia, active management of the sarcoidosis was reconsidered in case of neurosarcoidosis and for this, an MRI scan of the brain with the use of gadolinium needs to be undertaken first