Endocrine Abstracts

Case history: A 46-year-old female patient presented to A&E with a three day history of diarrhoea and vomiting, after three months of progressive weight loss. Her past medical history included chronic autoimmune thrombocytopaenia and Graves’ disease, which had been diagnosed four years earlier and treated with a brief course of propylthyuracil (PTU). She was clinically in extremis, with signs of severe cardiovascular and respiratory compromise and reduced responsiveness.

Investigations: Her investigations included standard biochemistry and full blood count, arterial blood gas, septic screen, urgent thyroid function tests and a bedside echocardiogram.

Results and treatment: Her baseline investigations revealed severe metabolic acidosis, neutrophilia, hyperglycaemia (17 mmol/l) and raised ketones. She was profoundly thyrotoxic, with a FT4 of 74 pmol/l, FT3 of 31 pmol/l and a fully suppressed TSH. She had echocardiographic evidence of global cardiomyopathy. She was diagnosed with a combination of diabetic ketoacidosis (new diagnosis of diabetes mellitus) and thyroid storm. She was intubated and transferred to intensive care on inotropic support, while anti-thyroid treatment was commenced with a combination of high-dose PTU (1,500 mg/day), propranolol, hydrocortisone and potassium iodate. Her haemodynamic instability, driven by thyrotoxicosis, was so severe that she required additional support by means of a cardiac pump and extra-corporeal membrane oxygenation (ECMO). She was also placed on a fixed rate insulin infusion, which readily controlled her glucose levels. Her clinical course was further complicated by the development of hepatitis, mandating a switch to carbimazole, and ischaemic bowel. She underwent three operations for ischaemic bowel and intra-abdominal bleeding.

Outcome and points for discussion: Thyroid hormone levels improved within six days, and returned to normal nine days after treatment initiation. Effective biochemical control was accompanied by a rapid improvement in cardiac contractility, ushering in a return to haemodynamic stability. After a prolonged intensive care stay, she was eventually discharged to her home on carbimazole and long-acting insulin. Thyroid storm remains the endocrine emergency with the highest mortality. Rapid control of thyroid function is essential but can be challenging. Modern, invasive means of cardiorespiratory support may have a role in severe cases, buying vital time until the thyroid function can be sufficiently controlled.