Multiple Sclerosis (MS)


Multiple sclerosis (MS) is a neurological disorder characterized by the demyelination of the brain and spinal cord due to the immune system attacking the myelin, which surrounds and protects the nerve fibers. This demyelination impedes the conduction of signals between the brain and the body. Symptoms include muscle weakness, visual dysfunction, cognitive problems, lack of coordination and balance, and sensory deficits such as numbness or tingling.1

Life Expectancy

While MS is typically not fatal, some of the disease-related symptoms may be life-threatening, including the development of severe infections and dysphagia, which may predispose an individual to aspiration pneumonia.2 

Compared to the general population, the lifespan for individuals with MS is reduced by about 5 to 10 years; however, this gap is decreasing as treatments for MS advance.2,3 On average, patients live 25 to 35 years following the initial diagnosis of MS.4

Common causes of death are often due to secondary complications from MS, including dysphagia and respiratory problems that lead to aspiration pneumonia, chronic urinary tract infections that can result in urogenital sepsis, and immobilization that causes chronic bed sores. Another cause of death is suicide, which is 7.5 times more likely among patients with MS than in the general population.4

Several factors contribute to a worse prognosis, including male sex, age at onset, an increased number of relapses per year, incomplete recovery from the first MS attack, shorter length of time between the initial attack and the first relapse, the accrual of significant disability between 2 to 5 years after disease onset, early cerebellar involvement, and a clinically isolated syndrome episode either causing predominantly motor symptoms or affecting multiple regions of the central nervous system.4

Sex Impact on MS Life Expectancy

A 60-year longitudinal study conducted in Norway showed that men with MS had a median life expectancy of 72.2 years, while men in the general population lived a median of 78.9 years. On the other hand, women with MS had a median life expectancy of 77.2 years, while women in the general population lived a median of 84.6 years.5

Age at Disease Onset  

The literature presents conflicting evidence on the effects of age at disease onset on prognosis. Some researchers found that patients with a lower age at onset had an increased risk of dying compared to patients who were older at disease onset.5 Others indicated that patients with relapsing-remitting MS who were older at disease onset had a more unfavorable prognosis associated with more rapid disease disability progression rate.6

In the Norwegian study, the researchers noted that the median survival from disease onset had more than doubled since the first study addressing this topic, which was published in 1969. Almost 50 years later in 2017, the median survival for people with MS had increased to 41 years.5 

Relapse Frequency/Incomplete Recovery

Women are more likely to have MS relapses than men. While women with MS do not frequently relapse during pregnancy, increased relapse activity occurs during the first postpartum trimester.7 

Relapses decrease in frequency over time, either due to older age or increased MS duration. More severe relapses typically occur in younger patients.7

Smoking increases the risk of relapse in patients with relapsing-remitting MS. Infections also correlate with increased relapse rate.7

The number of relapses is associated with permanent neurological disability. Incomplete recovery occurs after a substantial percentage of MS relapses, with 42% to 49% of relapses increasing the Expanded Disability Status Scale (EDSS) by 0.5 steps and 28% to 33% of relapses increasing the EDSS by 1 step.7

Initial 5 Years 

Relapses that occur within the first 5 years following disease onset increase the likelihood of more severe disease progression in the short term. Continued relapses in patients with an MS duration of over 10 years affect long-term disease progression and outcomes, but the impact of these relapses lessens over time.8

Early Cerebellar Involvement

Cerebellar ataxia is a common symptom of MS, especially in more progressive disease types. Typically, cerebellar involvement is associated with increased disability and worse disease prognosis.9

Clinically Isolated Syndrome

Clinically isolated syndrome (CIS) is the initial demyelinating event a patient with MS experiences, lasting a period of days to weeks. Patients experiencing multifocal demyelination or patients whose efferent motor nerves are predominantly affected during this CIS event are more likely to have increased disability and potentially life-threatening disease-related complications such as dysphagia, respiratory problems, or immobilization.10

Read more about clinically isolated syndrome

Immediate Treatment

To improve the life expectancy of patients with MS, it is critical that physicians immediately act to prevent progressive damage to the central nervous system, especially the brain which already has limited repair mechanisms. Early MS intervention is essential to optimize patient function, improve disease outcomes, and lengthen life expectancy.11 

References

  1. Multiple sclerosis. MedlinePlus. Updated June 1, 2021. Accessed May 17, 2022.
  2. Wexler M. MS prognosis and life expectancy. Multiple Sclerosis News Today. Updated May 5, 2022. Accessed May 17, 2022.
  3. Gower T. Does MS affect your life expectancy? WebMD. Accessed May 17, 2022.
  4. Lectures: prognosis. Spencer S. Eccles Health Sciences Library, University of Utah: Knowledge Weavers Project Archive. Accessed May 17, 2022.
  5. Lunde HMB, Assmus J, Myhr KM, Bø L, Grytten N. Survival and cause of death in multiple sclerosis: a 60-year longitudinal population study. J Neurol Neurosurg Psychiatry. 2017;88(8):621-625. doi:10.1136/jnnp-2016-315238
  6. Cierny D, Lehotsky J, Hanysova S, et al. The age at onset in multiple sclerosis is associated with patient’s prognosis. Bratisl Lek Listy. 2017;118(6):374-377. doi:10.4149/BLL_2017_071
  7. Kalincik T. Multiple sclerosis relapses: epidemiology, outcomes and management. A systematic review. Neuroepidemiology. 2015;44(4):199-214. doi:10.1159/000382130
  8. Tremlett H, Yousefi M, Devonshire V, Rieckmann P, Zhao Y; UBC Neurologists. Impact of multiple sclerosis relapses on progression diminishes with time. Neurology. 2009;73(20):1616-1623. doi:10.1212/WNL.0b013e3181c1e44f
  9. Wilkins A. Cerebellar dysfunction in multiple sclerosis. Front Neurol. 2017;8:312. doi:10.3389/fneur.2017.00312
  10. Tsang BKT, Macdonell R. Multiple sclerosis- diagnosis, management and prognosis. Aust Fam Physician. 2011;40(12):948-955.
  11. Cerqueira JJ, Compston DAS, Geraldes R, et al. Time matters in multiple sclerosis: can early treatment and long-term follow-up ensure everyone benefits from the latest advances in multiple sclerosis? J Neurol Neurosurg Psychiatry. 2018;89(8):844-850. doi:10.1136/jnnp-2017-317509

Reviewed by Harshi Dhingra, MD, on 5/27/2022.

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