Symptomatic improvement and clinical remission are the goals of therapy. Most, but not all, patients enjoy good quality of life and normal lifespan due to advances in diagnosis and immunosuppressive treatment. However, the onset of improvement varies greatly from days to months, and some patients have a significant burden of disease.
A prompt response to corticosteroid monotherapy is typical for older men with ocular MG whereas generalized symptoms are slower to improve and require more aggressive therapy. Chronic maintenance drug therapy is often required.
Patients with older age of onset and comorbidities, including other associated autoimmune diseases, typically have a poorer prognosis, although that may not always be the case.[33]Andersen JB, Heldal AT, Engeland A, et al. Myasthenia gravis epidemiology in a national cohort; combining multiple disease registries. Acta Neurol Scand Suppl. 2014;(198):26-31.
http://onlinelibrary.wiley.com/doi/10.1111/ane.12233/full
http://www.ncbi.nlm.nih.gov/pubmed/24588503?tool=bestpractice.com
[152]Gilhus NE, Nacu A, Andersen JB, et al. Myasthenia gravis and risks for comorbidity. Eur J Neurol. 2015 Jan;22(1):17-23.
http://www.ncbi.nlm.nih.gov/pubmed/25354676?tool=bestpractice.com
[153]Hansen JS, Danielsen DH, Somnier FE, et al. Mortality in myasthenia gravis: a nationwide population-based follow-up study in Denmark. Muscle Nerve. 2016 Jan;53(1):73-7.
http://www.ncbi.nlm.nih.gov/pubmed/25914186?tool=bestpractice.com
Disease exacerbation
Can occur due to infections, nonadherence to pharmacotherapy, addition of medications that can worsen MG, surgery, malignancy, administration of immune checkpoint inhibitors as cancer therapy, pregnancy, or other stressors.[3]Narayanaswami P, Sanders DB, Wolfe G, et al. International consensus guidance for management of myasthenia gravis: 2020 update. Neurology. 2021 Jan 19;96(3):114-22.
https://n.neurology.org/content/96/3/114.long
http://www.ncbi.nlm.nih.gov/pubmed/33144515?tool=bestpractice.com
[60]Safa H, Johnson DH, Trinh VA, et al. Immune checkpoint inhibitor related myasthenia gravis: single center experience and systematic review of the literature. J Immunother Cancer. 2019 Nov 21;7(1):319.
https://jitc.bmj.com/content/7/1/319.long
http://www.ncbi.nlm.nih.gov/pubmed/31753014?tool=bestpractice.com
[80]Chaudhuri A, Behan PO. Myasthenic crisis. 2009 Feb;102(2):97-107.
http://qjmed.oxfordjournals.org/content/102/2/97.full
http://www.ncbi.nlm.nih.gov/pubmed/19060020?tool=bestpractice.com
Myasthenic crisis can sometimes be averted with aggressive early intervention during an exacerbation.[81]Jani-Acsadi A, Lisak RP. Myasthenic crisis: guidelines for prevention and treatment. J Neurol Sci. 2007 Oct 15;261(1-2):127-33.
http://www.ncbi.nlm.nih.gov/pubmed/17544450?tool=bestpractice.com
Pregnancy
In one study of 35 pregnancies in 21 patients with MG, there were 30 live births. The symptoms of 50% of the women worsened in the second trimester (typically those with more severe MG); the other 50% either improved or remained stable. There was an increase in premature rupture of membranes (25.8%) and the most severe complications were abortion (11.4%) and fetal death (2.9%). A cesarean section was performed for two-thirds of births and spinal anesthesia was used in 73.3%. Neonatal MG was seen in 12.9% of live-born infants, and no predictors were found.[154]Ducci RD, Lorenzoni PJ, Kay CS, et al. Clinical follow-up of pregnancy in myasthenia gravis patients. Neuromuscul Disord. 2017 Apr;27(4):352-57.
http://www.ncbi.nlm.nih.gov/pubmed/28256306?tool=bestpractice.com