Endocrine Abstracts

When patients with type 1 diabetes present with hyponatremia, Addison’s is an important condition to exclude. It is however important to consider other causes, and a trial of hydrocortisone is not part of the diagnostic test for adrenal failure. A 43-year-old lady, with a background of Type 1 Diabetes and depression, presented unwell with hyponatremia. Her basal cortisol was low 162 nmol/l along with an ACTH 16.2 ng/l. A short synacthen test (SST) revealed a baseline cortisol of 229 nmol/l rising to 357 nmol/l at 30 minutes, and 462 nmol/l at 60 minutes, which was reported as a normal response. Her urine osmolarity was 597 mOsm/kg, consistent with SIADH, likely secondary to antidepressant use. The patient obtained a second opinion, and despite normal synacthen results, it was felt that “partial” adrenal insufficiency might be confirmed with a trial of hydrocortisone 5mg which was then increased to 10mg once a day, following which she subjectively felt better. So, the hydrocortisone was continued assuming she did have Addison’s disease. Lockdown then occurred in March 2020, so she spent over a year on 10mg hydrocortisone without further investigations. When seen in the Endocrinology clinic a year later, she had become Cushingoid with a weight gain of almost 30kgs and slight worsening of her diabetes control. She was weaned off the hydrocortisone, and over a few months lost about 26kg. She was managed with fluid restriction, and later a change of antidepressant, which led to near normalisation of her sodium levels. Learning point: Trials of therapy lead to false diagnoses, as patients may benefit from the placebo effect.