Case report

A 73-year-old man participated in a charity cycle ride in Kenya. He was usually very fit and, despite coronary artery bypass grafting 12 years previously, had participated in several similar events. He rode the first 4 days in full, covering 40 miles, off road, in average daily shade temperatures of 34°C. On the fifth day, he had an episode of lightheadedness and was hypotensive, with a resting pulse of 28 beats/min. He rested in the shade, drank copious oral fluids and was given 1 litre of normal (0.9%) saline intravenously. He remained bradycardic and hypotensive for 8 h but was asymptomatic while resting, with no chest pain or breathlessness. His cardiac rhythm could not be determined. He was not taking β-blockers.

The following day, his pulse and blood pressure had returned to normal but he did not cycle. He was asymptomatic, walking, eating and drinking normally. The next day, he relaxed at a hotel complex, drinking normal fluids, ate a celebratory meal in the evening but did not consume alcohol. At 23:00, he developed dysarthria and I was asked to examine him. He had mild left-sided arm and leg weakness (drift, National Institute of Health Stroke Scale score 1), left-sided sensory loss, sensory inattention, left homonymous hemianopia and visual inattention. There were some word finding difficulties. The total National Institute of Health Stroke Scale score was 10. An ambulance was arranged to take him to Mombasa Hospital.

Hospital management

On arrival, his neurological signs were unchanged. I cautiously introduced myself as a doctor travelling with the group and said that I specialised …