NICOTINE AND MYASTHENIA-GRAVIS WORSENING

We report a case of myasthenia gravis worsened by a nicotine transderm al system, in a man who usually was smoking fourty cigarettes per day without any worsening of his symptomatology. He noted an increased bil ateral ptosis, total ophtalmoplegia, difficulty in chewing and general ized weakness two hours after application of a nicotine transdermal sy stem, the symptoms improving after he removed it. Cholinergic receptor s involved in myasthenia gravis are nicotinergic, and their number at the neuromuscular junction is reduced in myasthenia gravis. That leads to a ''functionnal overdosage'' after application of the nicotine tra nsdermal system similar to the cholinergic crisis. This case can be co mpared with myasthenia syndromes described during the Second World War in tobacco chewers without any muscle impairment.