Anesthesia for thymectomy in children with myasthenia gravis.

Myasthenia gravis (MG) is an autoimmune disease with antibodies directed against the acetylcholine receptor at the neuromuscular junction (NMJ). Anesthetists have a special interest in myasthenia gravis because of its interaction with various anesthetic agents and because many myasthenics require a thymectomy to control their disease. Much has been written about the critical care management and anesthesia for adult myasthenic patients (1–6), but there is very little relating to modern pediatric anesthetic practice (7,8). In 1990, Brown et al. described the use of tubocurare and alcuronium in myasthenic children (7); neither of these drugs is currently available in the UK. This article discusses the anesthesia of children with autoimmune (or juvenile) myasthenia who present for thymectomy. However, it should be noted that the pediatric anesthetist may encounter two other forms of myasthenia gravis: neonatal myasthenia, a transient condition caused by the passage of antibodies from myasthenic mothers across the placenta and congenital myasthenia, a genetically inherited autosomal recessive disorder affecting the motor endplate (2,7,9,10). Neither of these conditions are associated with an abnormal thymus, so thymectomy is not indicated. We report three cases of thymectomy in children with juvenile myasthenia gravis and describe the clinical and physiological features of the disease. A discussion of the relevant pharmacology and the factors affecting anesthetic management is presented.