Childhood Myasthenia Gravis Pearls

1. Half of patients may be seronegative, but of those who have disease the treatment in many cases is similar to treatment of adult disease
2. Steroid, PE and IVIG all have been used safely during pregnancy. CI's should not be overused due to possibility of causing uterine contractions. Regional anesthesia or C section is preferred. Avoid Magnesium sulfate.
3. The slow channel congenital myasthenic syndrome (SCCMS) appears in later childhood or adolescence. It is associated with relatives with various adult onset MG subtypes. It is inherited as autosomal dominant. Neck flexor weakness, progressive myopathy, and failure to respond to CI's are common, as are skeletal deformities.
4. Pupillary hyporeflexia is relatively specific for congenital ach deficiency. Progressive myopathy occurs in it and SCCMS, as does non response to CI's. Congenital Ach deficiency also is associated with basal lamina on muscle surface.
5. Dok 7 mutation is associated with limb girdle myasthenia.
6. Fast channel syndrome occurs in infancy and early childhood and presents similarly to other conditions. it responds well to CI's and 3,4 DAP.