Newly diagnosed autoimmune Addison's disease in a patient with COVID-19 with autoimmune disseminated encephalomyelitis.

A man in his 20s with a history of acute disseminated encephalomyelitis (ADEM) was brought into the emergency department (ED) after his family found him at home collapsed on the floor unresponsive with a blood glucose of 28 mg/dL at the field. In the ED, the patient was tachycardic, tachypnoeic and hypotensive, requiring pressors and intubation at 9 hours and 12 hours after arrival, respectively. Laboratory results revealed a positive COVID-19 test, serum sodium of 125 mmol/L and persistent hypoglycaemia. The patient was given a high dose of dexamethasone for COVID-19 treatment 1 hour before pressors were started. He was then continued on a stress dose of intravenous hydrocortisone with rapid clinical improvement leading to his extubation, and discontinuation of vasopressors and glucose on day 2 of admission. The patient received his last dose of intravenous hydrocortisone on day 4 in the early afternoon with the plan to order adrenal testing the following morning prior to discharge. On day 5, the aldosterone <3.0 ng/dL, adrenocorticotropic hormone (ACTH) level >1250 pg/mL, and ACTH stimulation test showed cortisol levels of 3 and 3 µg/dL at 30 and 60 min, respectively. The anti-21-hydroxylase antibody was positive. The patient was discharged on hydrocortisone and fludrocortisone. The patient's symptoms, elevated ACTH, low cortisol and presence of 21-hydroxylase antibodies are consistent with autoimmune Addison's disease. This is the first case reporting autoimmune Addison's disease in a patient with COVID-19 with a history of ADEM. The case highlights the importance of considering adrenal insufficiency as a diagnostic differential in haemodynamically unstable patients with COVID-19.