What is multiple sclerosis?

From the Guidelines

The diagnosis of multiple sclerosis (MS) should be based on the 2010 McDonald criteria, which include the detection of lesions within the CNS that demonstrate dissemination in space (DIS) and dissemination in time (DIT), as well as the exclusion of alternative diagnoses. The 2010 McDonald criteria have substantially improved the diagnostic process in relapsing–remitting MS (RRMS) by increasing the sensitivity of the criteria and simplifying the features of both DIS and DIT, while maintaining the specificity of the earlier versions of the criteria 1.

The key features of the 2010 McDonald criteria include the focus on lesion location rather than lesion count, which facilitates MRI interpretation, and the acceptance of the concomitant presence of gadolinium-enhancing and gadolinium-nonenhancing lesions as evidence for DIT, allowing for very early diagnosis in some patients who undergo a single MRI examination at any time after symptom onset 1.

Some of the benefits of using the 2010 McDonald criteria include:

• Increased sensitivity for diagnosing MS
• Simplified features for DIS and DIT
• Ability to diagnose MS earlier in the disease course
• Reduced need for cerebrospinal fluid (CSF) testing

However, the 2010 McDonald criteria also have some limitations, particularly in primary progressive MS (PPMS), where brain MRI features can be normal and small spinal cord lesions might not be detected 1.

In terms of management, treatment typically involves disease-modifying therapies (DMTs) and symptom management, including corticosteroids for acute flare-ups, medications for specific symptoms, physical therapy, occupational therapy, and a healthy lifestyle with regular exercise, adequate rest, and stress management. The goal of treatment should be to reduce morbidity, mortality, and improve quality of life, and personalized treatment approaches are necessary due to the varying disease course among individuals.

From the Research

Definition and Prevalence of Multiple Sclerosis

• Multiple sclerosis (MS) is an autoimmune-mediated neurodegenerative disease of the central nervous system characterized by inflammatory demyelination with axonal transection 2.
• MS affects an estimated 900 000 people in the US, with a prevalence worldwide ranging from 5 to 300 per 100 000 people, increasing at higher latitudes 2.
• The disease typically presents in young adults aged 20 to 30 years, with a female to male sex distribution of nearly 3:1 2.

Diagnosis of Multiple Sclerosis

• Diagnosis is made based on a combination of signs and symptoms, radiographic findings (e.g., magnetic resonance imaging [MRI] T2 lesions), and laboratory findings (e.g., cerebrospinal fluid-specific oligoclonal bands), which are components of the 2017 McDonald Criteria 2, 3.
• The diagnosis of MS is made on clinicoradiological grounds to prove dissemination of disease in both time and space in the nervous system 3.

Treatment of Multiple Sclerosis

• Nine classes of disease-modifying therapies (DMTs) are available for relapsing-remitting MS and secondary progressive MS with activity, with varying mechanisms of action and routes of administration 2.
• These drugs include interferons, glatiramer acetate, teriflunomide, sphingosine 1-phosphate receptor modulators, fumarates, cladribine, and 3 types of monoclonal antibodies, with ocrelizumab approved for primary progressive MS 2.
• Interferon beta and glatiramer acetate have been mainstays of treatment in relapsing-remitting multiple sclerosis for two decades, with a history of development and known mechanisms of action 4.
• The efficacy rates of current DMTs, defined by reduction in annualized relapse rates compared with placebo or active comparators, range from 29%-68% 2.

Comparison of Disease-Modifying Therapies

• A systematic review compared the effectiveness of interferons-beta and glatiramer acetate in the treatment of people with relapsing-remitting MS, finding similar clinical efficacy at 24 months, but with higher relapse rates in the interferon group at 36 months 5.
• The effects of interferons-beta and glatiramer acetate on MRI lesion load accrual differ, with interferons-beta limiting the increase in lesion burden compared to glatiramer acetate 5.

Adherence to Disease-Modifying Therapies

• Nonadherence to disease-modifying drugs for MS is associated with poorer clinical outcomes, including higher rates of relapse and disease progression, and higher medical resource use 6.
• A systematic review and meta-analysis found that approximately one in five patients with MS do not adhere to, and one in four discontinue, daily oral DMDs before 1 year, highlighting opportunities to improve adherence and patient outcomes 6.