A 49-year-old man noticed a diminished sensation in his feet. Two months later, climbing stairs became difficult due to proximal muscle weakness of his legs. Over the next three months, sensory disturbances and both proximal and distal weakness progressed in arms and legs requiring the use of a walker or a wheelchair. Besides COPD, he was previously in a healthy condition. Based upon ancillary investigations, he was initially diagnosed with chronic inflammatory demyelinating polyneuropathy (CIDP), had received a course of intravenous Ig (IVIg), and was subsequently treated with high-dose corticosteroids (60 mg/day). He did not smoke or use drugs such as nitric oxide.

A 20-year-old previously healthy man suddenly noticed that he was unable to run. The next day he could not climb the stairs and lost strength in his arms. He was admitted to hospital, and over the next hours he progressively lost muscle power in his arms and legs. Swallowing was progressively impaired, and he noticed minor tingling in both hands and feet. He had had a minor upper respiratory tract infection a week prior to admission.

A 73-year-old-woman noticed pain in her right lower leg and thigh and left foot. After a few weeks of physiotherapy, she gradually developed tingling in her feet and a ‘plastic’ sensation in the soles of her feet. A few weeks later, her feet became completely numb, and she noticed painful tingling in her hands and around her left knee. Because of the tingling in her hands, she could barely use a fork and knife. Walking became difficult due to the dull feelings in her legs. Several drugs against painful neuropathy did not help. For years she had smoked two packs of cigarettes a week. A total of 50 pack-years was estimated.