Collapse and hypothermia in an elderly woman in early summer

A 74-year-old woman was admitted during a warm spell, having been found at home collapsed. She was conscious but confused (Abbreviated Mental Test score (AMTS) 4/10). Her sister related her medical history which included an underactive thyroid diagnosed 8 years before, an operation to close an atrial septal defect as a young woman, a small stroke and several admissions over the last 3–4 years with difficulty coping and confusion. In fact, she had been told by one doctor that her sister had dementia. The patient was taking digoxin 62.5 μg, co-amilofruse 2 tablets, and thyroxine 50 μg, all once daily. On examination she was pale and drowsy and her rectal temperature was 33.6°C. Body hair was absent. The pulse rate was 60 beats/min, irregularly irregular, and her blood pressure was 120/60 mmHg. Although the heart was clinically enlarged, auscultation was …