Endocrine Abstracts

Primary hypothyroidism and hypoadrenalism may occur concomitantly as part of autoimmune endocrine syndromes. Thyroxine replacement without steroid replacement can precipitate fatal adrenal crisis in this subgroup of patients. We report two patients with autoimmune primary hypothyroidism presenting with acute adrenal crises after commencing thyroxine replacement.

Case 1: A 36-year-old patient with type 1 diabetes for 15 years was admitted with vomiting, abdominal pain and syncopal episodes. He was hypotensive (BP 80/50 mmHg), the blood glucose was 2.1 mmol/l, sodium 130 mmol/l, potassium 4.1 mmol/l, urea 6.1 mmol/l and random cortisol 50 nmol/l. Hypoadrenalism was suspected and confirmed after a short synacthen test (pre-test cortisol 56 nmol/l, 30-min post 63 nmol/l). He improved with intravenous hydrocortisone, fluids and insulin. He had weight loss, hypoglycaemia and recurrent syncope when he was diagnosed with hypothyroidism 1 month earlier but despite increasing thyroxine doses, had no improvement in symptoms.

Case 2: A 56-year-old gentleman was admitted with progressive weight loss, loss of appetite and lassitude. Six weeks earlier, he had been commenced on 50 μg of thyroxine after a diagnosis of subclinical hypothyroidism (TSH 11.4 MU/l, T₄ 15.4 pmol/l, TPO antibodies 343 IU/ml) after which his symptoms progressively worsened. At admission he was in adrenal crisis with severe postural symptoms, hypotension, hyperkalemia (6.8 mmol/l) and hyponatremia (122 mmol/l). Renal function was impaired (urea 9.9 mmol/l, creatinine162 umol/l). Treatment with intravenous fluid and steroids led to complete resolution of symptoms and biochemical abnormalities. Short synacthen test confirmed adrenal insufficiency (pre-test cortisol 93 nmol/l and post 90 nmol/l).

Both patients are doing well on adequate glucocorticoid and minerelocorticoid replacement.

Discussion: Adrenal insufficiency is difficult to diagnose due to non-specific symptoms and a high index of suspicion is required especially in the presence of other autoimmune disorders. Weight loss in the context of hypothyroidism should alert us to concomitant adrenal insufficiency.