Neuromuscular disorder characterized by muscle
weakness and rapid muscle fatigue. Usually apparent during adulthood; onset
may occur at any age. Most individuals present eyelid ptosis, diplopia, and
excessive muscle fatigue following exercise. Other clinical features commonly include
dysarthria, dysphagia, and proximal limb weakness. Approximately 10% may
develop potentially life-threatening complications as a consequence of
severe respiratory depression (myasthenic crisis).
Goldflam-Erb Disease; Erb Syndrome; Erb-Goldflam Disease;
Erb-Oppenheim-Goldflam Syndrome; Hoppe-Goldflam Syndrome; Hoppe-Goldflam
Syndrome Complex; Asthenic Bulbar Paralysis; Bulbospinal Paralysis;
Myasthenia Gravis Pseudoparalytica.
Classic Generalized Myasthenia Gravis
Ocular Myasthenia Gravis
Transitory Neonatal Myasthenia Gravis
Juvenile Myasthenia Gravis
Congenital Myasthenia Gravis
Familial Infantile Myasthenia Gravis
Congenital Endplate Acetylcholinesterase Deficiency
Slow Channel Syndrome
Fast Channel Syndrome
The first written description of myasthenia gravis is granted to
Thomas Willis (1621-1675), an English physician, who published a book in 1672 entitled:
De anima brutorum in which he wrote about “a woman who temporarily lost
her power of speech and became `mute as a fish.'" This was subsequently
interpreted as myasthenia gravis. Thomas Willis was born in Great Bedwin, a
Wiltshire village in England. He graduated from Oxford University Legion with a Bachelor
of Medicine in 1646. In 1660 he was appointed Sedleian Professor of Natural
Philosophy at Oxford and given the diploma of MD. The earliest description of the disease
was done by Samuel Wilks, an English physician, in 1877 which was reported in
Guy's Hospital Reports 22:7. However, it seems that it was a case of “bulbar
paralysis." Aleksei Kozhevnikov, a Russian physician, described a
“progressive familial spastic diplegia” and wrote on the neuropathology of
nuclear ophtalmoplegia, myasthenia, and bulbar paralysis. His textbook on
nervous diseases was a popular manual because of its brevity and lucidity. He was
born in Ryazan and entered the University of Moscow in 1853 and received his MD in 1860.
He later studied abroad in Germany, England, Switzerland, and France. Wilhem Heinrich Erb (1840-1921), a German
neurologist, was responsible (in part) for the delineation of myasthenia gravis
(called Erb-Goldflam-Oppenheim disease at the time). Finally, the use of physostigmine in the treatment
of myasthenia gravis is granted to Mary Broadfoot Walker (1896-1974), a salaried
Assistant Medical Officer in “Poor Law Service" at St. Alfege's Hospital, Greenwich, England, who
introduced it in 1934.
Prevalence in general population is 50 to 125:1 million.
Sporadic for acquired cases.
In acquired cases, there is a decrease in the number of
acetylcholine receptors (AChR) at the neuromuscular junction. This decrease
is secondary to circulating antibodies against AChR, which increase the rate
of degradation of AChR and decrease its rate of synthesis. These antibodies
are present in 80 to 90% of the classic and juvenile forms of myasthenia;
their production occurs in the thymus. The thymus is abnormal in 80 to
90% of those patients: thymic follicular hyperplasia (65-75%),
thymoma (10%, only in adults), and ...