The epidemiology of transverse myelitis (TM) depends on its underlying cause. The annual incidence of idiopathic complete TM is uncertain as most studies precede the discovery of the aquaporin-4-IgG and myelin oligodendrocyte glycoprotein-IgG autoantibodies. These autoantibodies have provided a definable etiology for some TM cases previously thought to be idiopathic.[10]Sechi E, Shosha E, Williams JP, et al. Aquaporin-4 and MOG autoantibody discovery in idiopathic transverse myelitis epidemiology. Neurology. 2019 Jul 23;93(4):e414-20.
http://www.ncbi.nlm.nih.gov/pubmed/31235660?tool=bestpractice.com
[11]Zalewski NL, Flanagan EP, Keegan BM. Evaluation of idiopathic transverse myelitis revealing specific myelopathy diagnoses. Neurology. 2018 Jan 9;90(2):e96-e102.
http://www.ncbi.nlm.nih.gov/pubmed/29247071?tool=bestpractice.com
One 2021 retrospective review using the National US Veterans Health Administration database from 1999 to 2015 showed a point prevalence of 7.86 cases of TM per 100,000 people. Of the 961 patients, 31.8% of them were diagnosed with disease-associated TM and 68.2% were diagnosed with idiopathic TM.[12]Abbatemarco JR, Galli JR, Sweeney ML, et al. Modern look at transverse myelitis and inflammatory myelopathy: epidemiology of the National Veterans Health Administration Population. Neurol Neuroimmunol Neuroinflamm. 2021 Aug 31;8(6):e1071.
https://www.neurology.org/doi/10.1212/NXI.0000000000001071
http://www.ncbi.nlm.nih.gov/pubmed/34465615?tool=bestpractice.com
Acute partial TM commonly heralds or accompanies multiple sclerosis (MS), which affects up to 0.3% of people of Northern European ancestry.[13]Compston A, Coles A. Multiple sclerosis. Lancet. 2008 Oct 25;372(9648):1502-17.
http://www.ncbi.nlm.nih.gov/pubmed/18970977?tool=bestpractice.com
The pattern of longitudinally extensive TM is commonly associated with neuromyelitis optica spectrum disorder (NMOSD), which may account for approximately 1% of all central nervous system demyelinating disease in North American and European populations, a somewhat greater proportion in African-American and Hispanic populations, up to 30% in the Japanese population, and virtually all cases in ethnic or racial groups in which typical MS is virtually absent, such as aboriginal peoples of North America and black Africans.[9]Wingerchuk DM, Lennon VA, Lucchinetti CF, et al. The spectrum of neuromyelitis optica. Lancet Neurol. 2007 Sep;6(9):805-15.
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[14]Kira J. Multiple sclerosis in the Japanese population. Lancet Neurol. 2003 Feb;2(2):117-27.
http://www.ncbi.nlm.nih.gov/pubmed/12849268?tool=bestpractice.com
Onset may occur at any age. MS-associated cases typically occur between ages 20 and 50 years (median about 29 years) whereas the median onset age for NMOSD cases is about a decade later.[4]Wingerchuk DM, Hogancamp WF, O'Brien PC, et al. The clinical course of neuromyelitis optica (Devic's syndrome). Neurology. 1999 Sep 22;53(5):1107-14.
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[13]Compston A, Coles A. Multiple sclerosis. Lancet. 2008 Oct 25;372(9648):1502-17.
http://www.ncbi.nlm.nih.gov/pubmed/18970977?tool=bestpractice.com
There is a female predominance in all subtypes.[12]Abbatemarco JR, Galli JR, Sweeney ML, et al. Modern look at transverse myelitis and inflammatory myelopathy: epidemiology of the National Veterans Health Administration Population. Neurol Neuroimmunol Neuroinflamm. 2021 Aug 31;8(6):e1071.
https://www.neurology.org/doi/10.1212/NXI.0000000000001071
http://www.ncbi.nlm.nih.gov/pubmed/34465615?tool=bestpractice.com
These syndromes also affect children, although the incidence is unknown. The treatment of TM in children is usually the same as in adults.[15]Chabas D, Strober G, Waubant E. Pediatric multiple sclerosis. Curr Neurol Neurosci Rep. 2008 Sep;8(5):434-41.
http://www.ncbi.nlm.nih.gov/pubmed/18713581?tool=bestpractice.com
[16]Banwell B, Tenembaum S, Lennon VA, et al. Neuromyelitis optica-IgG in childhood inflammatory demyelinating CNS disorders. Neurology. 2008 Jan 29;70(5):344-52.
http://www.ncbi.nlm.nih.gov/pubmed/18094334?tool=bestpractice.com
[17]McKeon A, Lennon VA, Lotze T, et al. CNS aquaporin-4 autoimmunity in children. Neurology. 2008 Jul 8;71(2):93-100.
http://www.ncbi.nlm.nih.gov/pubmed/18509092?tool=bestpractice.com
The epidemiology of other infectious and inflammatory myelopathies varies depending on the underlying etiology.