Clinical manifestations of myasthenia gravis
- Shawn J Bird, MD
Shawn J Bird, MD
- Professor of Neurology
- University of Pennsylvania School of Medicine
- Section Editors
- Jeremy M Shefner, MD, PhD
Jeremy M Shefner, MD, PhD
- Section Editor — Neuromuscular Disease
- Professor and Chair of Neurology, Barrow Neurological Institute
- Professor of Neurology, University of Arizona, Phoenix
- Clinical Professor of Neurology, Creighton University
- Ira N Targoff, MD
Ira N Targoff, MD
- Section Editor — Muscle Disease
- Professor of Medicine, Section of Rheumatology
- University of Oklahoma Health Sciences Center
Myasthenia gravis is the most common disorder of neuromuscular transmission. It is now one of the best characterized and understood autoimmune disorders. The hallmark of the disorder is a fluctuating degree and variable combination of weakness in ocular, bulbar, limb, and respiratory muscles. Weakness is the result of an antibody-mediated, T-cell dependent immunological attack directed at proteins in the postsynaptic membrane of the neuromuscular junction (acetylcholine receptors and/or receptor-associated proteins). The diagnosis of myasthenia gravis can be established by clinical and serologic testing [1,2].
The clinical manifestations of myasthenia gravis will be reviewed here. Other aspects of this disorder are discussed separately. (See "Ocular myasthenia gravis" and "Diagnosis of myasthenia gravis" and "Differential diagnosis of myasthenia gravis" and "Pathogenesis of myasthenia gravis" and "Treatment of myasthenia gravis".)
There are two clinical forms of myasthenia gravis: ocular and generalized.
●In ocular myasthenia, the weakness is limited to the eyelids and extraocular muscles. (See "Ocular myasthenia gravis".)
●In generalized disease, the weakness commonly affects ocular muscles, but it also involves a variable combination of bulbar, limb, and respiratory muscles.
- Silvestri NJ, Wolfe GI. Myasthenia gravis. Semin Neurol 2012; 32:215.
- Keesey JC. Clinical evaluation and management of myasthenia gravis. Muscle Nerve 2004; 29:484.
- Carr AS, Cardwell CR, McCarron PO, McConville J. A systematic review of population based epidemiological studies in Myasthenia Gravis. BMC Neurol 2010; 10:46.
- Heldal AT, Eide GE, Gilhus NE, Romi F. Geographical distribution of a seropositive myasthenia gravis population. Muscle Nerve 2012; 45:815.
- Mombaur B, Lesosky MR, Liebenberg L, et al. Incidence of acetylcholine receptor-antibody-positive myasthenia gravis in South Africa. Muscle Nerve 2015; 51:533.
- Breiner A, Widdifield J, Katzberg HD, et al. Epidemiology of myasthenia gravis in Ontario, Canada. Neuromuscul Disord 2016; 26:41.
- Santos E, Coutinho E, Moreira I, et al. Epidemiology of myasthenia gravis in Northern Portugal: Frequency estimates and clinical epidemiological distribution of cases. Muscle Nerve 2016; 54:413.
- Grob D, Brunner N, Namba T, Pagala M. Lifetime course of myasthenia gravis. Muscle Nerve 2008; 37:141.
- Phillips LH. The epidemiology of myasthenia gravis. Semin Neurol 2004; 24:17.
- Boldingh MI, Maniaol AH, Brunborg C, et al. Increased risk for clinical onset of myasthenia gravis during the postpartum period. Neurology 2016; 87:2139.
- Phillips LH 2nd, Torner JC, Anderson MS, Cox GM. The epidemiology of myasthenia gravis in central and western Virginia. Neurology 1992; 42:1888.
- Andrews PI. Autoimmune myasthenia gravis in childhood. Semin Neurol 2004; 24:101.
- Thorlacius S, Aarli JA, Riise T, et al. Associated disorders in myasthenia gravis: autoimmune diseases and their relation to thymectomy. Acta Neurol Scand 1989; 80:290.
- Kister I, Gulati S, Boz C, et al. Neuromyelitis optica in patients with myasthenia gravis who underwent thymectomy. Arch Neurol 2006; 63:851.
- McKeon A, Lennon VA, Jacob A, et al. Coexistence of myasthenia gravis and serological markers of neurological autoimmunity in neuromyelitis optica. Muscle Nerve 2009; 39:87.
- Leite MI, Coutinho E, Lana-Peixoto M, et al. Myasthenia gravis and neuromyelitis optica spectrum disorder: a multicenter study of 16 patients. Neurology 2012; 78:1601.
- Grob D, Arsura EL, Brunner NG, Namba T. The course of myasthenia gravis and therapies affecting outcome. Ann N Y Acad Sci 1987; 505:472.
- Oosterhuis HJ. The natural course of myasthenia gravis: a long term follow up study. J Neurol Neurosurg Psychiatry 1989; 52:1121.
- Bever CT Jr, Aquino AV, Penn AS, et al. Prognosis of ocular myasthenia. Ann Neurol 1983; 14:516.
- Sommer N, Melms A, Weller M, Dichgans J. Ocular myasthenia gravis. A critical review of clinical and pathophysiological aspects. Doc Ophthalmol 1993; 84:309.
- Weinberg DH, Rizzo JF 3rd, Hayes MT, et al. Ocular myasthenia gravis: predictive value of single-fiber electromyography. Muscle Nerve 1999; 22:1222.
- Pal S, Sanyal D. Jaw muscle weakness: a differential indicator of neuromuscular weakness--preliminary observations. Muscle Nerve 2011; 43:807.
- Sih M, Soliven B, Mathenia N, et al. Head-drop: A frequent feature of late-onset myasthenia gravis. Muscle Nerve 2017; 56:441.
- Werner P, Kiechl S, Löscher W, et al. Distal myasthenia gravis frequency and clinical course in a large prospective series. Acta Neurol Scand 2003; 108:209.
- Mantegazza R, Beghi E, Pareyson D, et al. A multicentre follow-up study of 1152 patients with myasthenia gravis in Italy. J Neurol 1990; 237:339.
- Hansen JS, Danielsen DH, Somnier FE, et al. Mortality in myasthenia gravis: A nationwide population-based follow-up study in Denmark. Muscle Nerve 2016; 53:73.