The History of Myasthenia Gravis

ABSTRACT

Since Willis described 'fatigable weakness' in 1672, most physicians consider it as a kind of hysteria due to the inconsistent fluctuation of symptoms. Erb presented three cases of 'bulbal palsy' in the 1870s, and Oppenheim and Hopper considered myasthenia gravis as a disease similar to curare poisoning and as a disease induced by attack of the motor centers by intrinsic toxins, respectively. In 1903, Elliot suggested that a 'chemical substance' mediates the nerve impulses at synapse. However, it was not until 1921 that this was demonstrated by Loewi, who provided evidence from the famous two-frog-hearts experiment. Dale later revealed the substance to be acetylcholine, and he also suggested that myasthenia gravis is due to a problem with the motor end plate. In 1934, Walker was prompted by the resemblance between myasthenia gravis and curare poisoning to apply physostigmine, a curare-poisoning antidote, to a patient, which produced a dramatic result. Since then the use of anticholinesterase inhibitors has been adopted for standard therapeutic modality. Some prominent surgeons have also applied thymectomy as a surgical modality. The most recent focus of myasthenia gravis has been immunological. In 1960, Simpson proposed the autoimmune hypothesis, and Chang et al. showed that snake venom contained a selective antagonist of the nicotinic acetylcholine receptor, alpha-bungarotoxin. The immunization of rabbits with acetylcholine receptor purified from the electrical organs of electric eels by Patrick et al. induced myasthenic symptoms and signs, and these were reversed by acetylcholinesterase inhibitors. The role of the autoimmune system has led to the introduction of an immunosuppressive modality and plasma exchange to the field of clinical neurology.