FCP2-403

A 77-year-old woman is admitted in an unconscious state. On examination in casualty, her temperature is 33 °C and she was in left ventricular failure.
Her blood glucose level is 5.7 mmol/l and random cortisol is elevated. Free T4 is 4.4 pmol/l.
A CT scan of her brain reveals no focal lesion and a cursory assessment reveals no gross focal neurology.

Which diagnosis fits best with this woman’s clinical picture?