Endocrinology and Diabetes Mellitus: Diabetes Emergencies, Thyroid, Adrenal and Calcium
Core concepts
Endocrinology requires confident management of diabetes, diabetic ketoacidosis (DKA) and hyperosmolar hyperglycaemic state (HHS), thyroid disease, adrenal insufficiency, Cushing syndrome, calcium disorders, pituitary disease and sodium disorders. Know diagnostic criteria for diabetes: fasting glucose at least 7.0 mmol/L, 2-hour glucose at least 11.1, HbA1c at least 6.5%, or random at least 11.1 with symptoms. DKA management prioritises fluids, potassium assessment, insulin infusion and treatment of precipitating causes. Thyroid function tests must be interpreted with TSH, free T4 and clinical context. Adrenal crisis needs immediate hydrocortisone after or alongside blood tests, not delayed treatment.
Traps
Euglycaemic DKA occurs with SGLT2 inhibitors. In DKA, insulin can be started only when potassium is at least 3.3 mmol/L; otherwise replace potassium first. Corrected calcium must be calculated in hypoalbuminaemia. Sick euthyroid syndrome can produce abnormal thyroid tests; do not treat without evidence. In suspected adrenal crisis, take samples but give steroids immediately. Beware of over-rapid correction of hypernatraemia or hyponatraemia.
Worked example / rule of thumb
A 22-year-old with type 1 diabetes has glucose 26 mmol/L, pH 7.10, bicarbonate 8 mmol/L, ketones 5 mmol/L and potassium 3.0 mmol/L. Diagnose DKA. Give isotonic saline, replace potassium before starting insulin, then start a fixed-rate insulin infusion and add dextrose when glucose falls below 12-14 mmol/L. Rule: in DKA, potassium comes before insulin when K+ is below 3.3 mmol/L.