Endocrine Abstracts

This case of a young adult patient presenting with autoimmune primary adrenal insufficiency highlights several important diagnostic and management considerations that trainee Endocrinologists should be aware of. This 30-year-old male with no significant past medical history presented to the Emergency Department with a two-week history of dizziness, weight loss and vomiting. Examination revealed hypotension and several hyperpigmented skin patches overlying the spine. Bloods revealed severe hypoosmolar hyponatraemia with a serum sodium of 117 mmol/l (ref 133 – 146 mmol/l) and serum osmolality 242 mOsmol/Kg (ref 275-295 mOsmol/Kg). A random serum cortisol was 84 nmol/l, prompting the completion of a Short Synacthen Test (SST) which demonstrated a sub-optimal adrenal response (Table 1). A provisional diagnosis of primary adrenal insufficiency was made, and the patient was commenced on corticosteroid and mineralocorticoid replacement with hydrocortisone 10/5/5 mg and fludrocortisone 100 micrograms daily respectively. He received education on adrenal insufficiency, including sick day steroid rules and teaching on how to administer an emergency intramuscular hydrocortisone injection. This patient had undergone a healthy childhood with no intellectual delay or behavioural issues, however for completeness he was screened for adrenoleukodystrophy via plasma very long chain fatty acids. The result was normal. Adrenal cortex antibodies subsequently returned positive, thereby confirming a diagnosis of autoimmune primary adrenal insufficiency (PAI) Given the association between autoimmune PAI and other autoimmune endocrinopathies, the patient also underwent baseline screening for Coeliac disease, Type 1 Diabetes Mellitus and autoimmune thyroid disease. This screening was negative but will need to be repeated at regular intervals as part of long term follow up. Two months after originally presenting he was seen in the Endocrinology clinic where he reported significantly improved wellbeing and energy levels. Examination revealed ongoing hyperpigmented patches overlying the spine which the patient felt were unchanged. Clinic bloods demonstrated an elevated plasma renin of 321 mIU/l (ref 3.4-56 mIU/l), suggesting inadequate mineralocorticoid replacement, and prompting an increase to his fludrocortisone dose.