TY - CHAP M1 - Book, Section TI - Chapter 31. Myasthenia Gravis A1 - Atchabahian, Arthur A2 - Atchabahian, Arthur A2 - Gupta, Ruchir PY - 2013 T2 - The Anesthesia Guide AB - Autoimmune disease where antibodies are produced to the (postsynaptic) acetylcholine (ACh) receptor of neuromuscular junction (NMJ), possibly originating in thymusTen percent of patients have congenital myasthenia with abnormal ACh receptors; cholinesterase inhibitors will be ineffective in these patientsResults in functionally decreased (70–80%) number of postsynaptic receptorsIncidence of about 1:10,000Before age of 40 years, 2F/1M, 40% thymus enlargementAfter age of 40 years, 1F/1M, 20% thymomaMost commonly affects ocular muscles, but can affect any skeletal muscle, including muscles of respirationCharacterized by skeletal muscle weakness that improves with restClinical course often marked by periods of exacerbations and remissionsTreatment:Cholinesterase inhibitors to increase amount of ACh at NMJCorticosteroidsImmunosuppression (mycophenolate mofetil, azathioprine, cyclosporine, tacrolimus, and occasionally cyclophosphamide)Plasmapheresis to remove antibodies, IVIgThymectomyPregnancy:Worsening in first 4 months, at delivery, and postpartum (up to 3 weeks)Optimize therapy; immunosuppressants are contraindicatedEpidural for delivery or c/s; avoid high level; consider ropivacaine (less motor block)Breastfeeding OK if well controlledNeonatal myasthenia (antibodies cross placenta) in 20–30%: weak cry, difficulty feeding, occasional respiratory distress; treat with cholinesterase inhibitors, plasmapheresis SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/29 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=57260708 ER -