[Long-term treatment of Lambert-Eaton syndrome by 3, 4 diaminopyridine]

A patient with a 5 year history of slow-progressive Lambert-Eaton Myasthenic Syndrome (LEMS) was treated for a period of 12 months with 3,4-diaminopyridine (3,4-DAP). The therapy led to an objective increase in muscle power. During the treatment period, there was no increase in muscle weakness, but attempts at withdrawal of the drug confirmed a progression. The mouth dryness disappeared and autonomic regulation disturbances were improved. All of the laboratory parameters remained unchanged. A neoplasia was excluded by extensive endoscopic and radiological investigations. Side-effects included initial perioral paresthesia and, later, paresthesia down the skin and along the ulnar edge of the forearm. 3,4-DAP seems to be an effective and acceptable long-term symptomatic therapy in LEMS.