CASE 1

A 40-year-old man of Chinese descent presented with severe weakness. I was asked to review him in the intensive care unit where he had been admitted with a diagnosis of Guillain-Barré syndrome (GBS). He had not required intubation and was able to give his own history.

He had been entirely well with no past history of note until three months previously when he first experienced severe cramping in his thigh muscles at night, usually around three o’clock in the morning. He would wake up and walk around for about 30 minutes, with stiff legs, take a non-steroidal anti-inflammatory and return to bed. The symptoms would rapidly settle and he would awake the next morning well. Over the eight weeks before admission he had experienced two bouts of “flu-like illness”. He felt that he was “run down” and began drinking an energy sports drink to improve his general condition. After the second episode, his general practitioner, concerned about the ongoing cramping, referred him to a physician. After several blood investigations the physician diagnosed Grave’s disease about four weeks before the current admission and started him on neomercazole. Despite the neomercazole he continued to experience intermittent thigh muscle cramps in the early hours of the morning, but otherwise felt entirely well. He was physically active and exercised regularly. On the day before admission he had played rugby at a school reunion after which he joined friends for a hearty meal, but he did not drink any alcohol. At 03:00 he again awoke with severe cramping, but on this occasion it did not resolve and by 06:00 he was unable to move his arms or legs. He had not been incontinent and was able to void urine normally, and he had no sensory symptoms. On arrival in the accident and emergency department he …