How different are late onset and adult onset MS really?

Late-onset multiple sclerosis (LOMS) is different from adult-onset (AO)MS in various ways. Dr Celine Louapre (Sorbonne University, France) talked about the clinical and imaging features of LOMS to inform the audience about this condition.

“LOMS is usually defined as MS diagnosed after 50 years of age,” said Dr Louapre. “It is a condition that is susceptible to misdiagnosis, due to comorbidities and differential diagnoses such as cervical myopathy, polyneuropathy, stroke, and Meniere disease.”

Just as in AOMS, more women are affected by LOMS (around 64.5%) [1,2]. There is a strongly increased risk for a progressive course of the disease in LOMS [3] but there are fewer relapses in the first years of LOMS than in the first years of AOMS [4]. “The annual relapse rate is however higher in the first years of LOMS than in patients with AOMS who have longer disease duration,” added Dr Louapre. Next to this, LOMS is associated with a more rapid evolvement of disability than AOMS [5]. “The time to be unable to walk is significantly shorter in patients with LOMS but still at an older age than in AOMS [6],” according to Dr Louapre. Brainstem, spinal, and supratentorial involvement at diagnosis have been associated with an increased risk for disability in LOMS [7]. “These findings were however not confirmed in other studies,” Dr Louapre nuanced.

Furthermore, the symptoms at onset are somewhat different for patients with LOMS than for those with AOMS. Visual symptoms and numbness may be more common in AOMS, whereas LOMS has been associated with a higher incidence of bowel/urinary complaints, fatigue, muscle weakness, and spasms at onset [6,8].

“The imaging features we see at diagnosis in LOMS are broadly comparable to what we observe in AOMS,” said Dr Louapre. Brain lesions and spinal cord lesions are seen in 73% and 64% of the patients with LOMS, respectively [9]. Gadolinium-enhanced lesions may be somewhat less common in patients with LOMS than in those with AOMS [10]. Finally, over time, less MRI activity was observed in LOMS versus AOMS [11]. “This may be an effect of age itself more than age at onset,” commented Dr Louapre.

“The different clinical and imaging features of LOMS and AOMS may be linked to the fact that AOMS is associated with more inflammation and active focal demyelination, whereas remyelination impairment and neurodegeneration are more typical elements of LOMS,” Dr Louapre ended.

1. Louapre C, et al. Clinical and neuroimaging features of late-onset multiple sclerosis. 10th EAN Congress, 29 June–2 July 2024, Helsinki, Finland.
2. Naseri A, et al. Mult Scler Relat Disord. 2021;50:102816.
3. Stankoff et al. Neurology. 2007;68(10):779-81.
4. Zinganell A, et al. J Neurol. 2024;271(2):674-687.
5. Andersen MA, et al. J Neurol. 2021;268(9):3352-3360.
6. Knowles S, et al. Ann Neurol. 2024;95(3):471-486.
7. Lorefice L, et al J Neurol. 2024;271(4):1630-1637.
8. Palathinkara M, et al. Mult Scler Relat Disord. 2023:80:105132.
9. Nasiri E, et al. J Neuroradiol. 2023;50(6):571-580.
10. Mirmosayyeb O, et al. J Clin Med. 2020;9(5):1326.
11. D’Amico E, et al. Eur J Neurol. 2018;25(12):1425-1431.

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Posted on 25 July 202425 July 2024