Introduction And Objectives
Myasthenia gravis (MG) is a chronic autoimmune disease caused by a defect in neuromuscular transmission. This results from the binding of autoantibodies to signaling proteins, and especially the nicotinic acetylcholine receptor (AChR) at the neuromuscular junction. At least three mechanisms have been proposed to explain how anti-AChR antibodies compromise neuromuscular transmission: (i) complement binding and activation at the neuromuscular junction; (ii) accelerated degradation of AChR molecules (antigenic modulation); and (iii) functional blocking of AChR-binding sites. MG is characterized by muscle fatigability, exacerbated by repetitive use of the affected muscle.
Its prevalence is estimated at 14.2 per 100,000 people. The epidemiological distribution by gender is bimodal: young women under 40 years old, peaking between 20 and 29 years old. In men the mean age of onset is later, and the peak is at around 50 years old. These were traditionally thought to be the most widely affected groups, although the number of cases among the population older than 70 years old has been increasing worldwide in recent years.
Our Multidisciplinary Myasthenia Gravis Unit in Vall Hebron University Hospital in Barcelona, was established by Dr José María Ponseti (senior FACS) in 1969. His experience has been passed on to neurologists and thoracic surgeons interested in MG, and we currently provide comprehensive medical and surgical treatment for the disease. Our multidisciplinary Unit consists of neurologists specializing in neuromuscular disorders, pneumologists, rehabilitation specialists, thoracic surgeons, oncologists and anesthetists. More than 400 myasthenic patients are being treated by our Unit. Two trials are ongoing at our centre – one for refractory myasthenias.
First-line therapies include acetylcholinesterase inhibitors and oral steroids. However, many patients do not tolerate corticoids, and as such second- and third-line immunosuppressants must be considered. Patients with myasthenia found to have hyperplasia or thymoma in the imaging techniques (CT or MRI) must be evaluated by a committee including neurologists, thoracic surgeons, oncologists and anesthetists. Our Unit’s thoracic surgeons have extensive experience in extended videoscopic thymectomy and transsternal thymectomy. Our team has expertise in handling complications and managing myasthenic crises, while the anesthetists and intensive care specialists in our Myasthenia team play an important role in preventing myasthenic crises.Finally, our obstetricians and neonatologists provide care during pregnancy and for newborns.