Multiple Sclerosis

Definition/ diagnostic criteria Multiple sclerosis (MS) is a chronic, immune-mediated condition that affects the central nervous system (CNS) and is characterised by demyelination and axonal damage. Diagnostic criteria include evidence of dissemination in space and time of CNS lesions, determined by clinical assessment and MRI findings. CSF analysis for oligoclonal bands may support the diagnosis in ambiguous cases.

Epidemiology MS is one of the most common neurological conditions among young adults in the UK. The prevalence is approximately 190 per 100,000, with a higher incidence in women. There is a notable north-south gradient in incidence within the UK, with Scotland having one of the highest rates globally.

Diagnosis
Clinical features: Typical initial symptoms include optic neuritis, sensory disturbances, limb weakness, gait disturbance, and balance issues. MS can present in various patterns:

• The most common is relapsing-remitting MS (RRMS), which is characterised by discrete episodes of neurological dysfunction (relapses), followed by periods of remission.
• Secondary progressive where (SPMS) where there is a gradual increase in disability unrelated to relapses, which become less frequent or stop completely (about two thirds of people with RRMS progress to SPMS)
• Primary progressive MS (PPMS) which involves a steady deterioration of the disease from the onset, without remissions.

Investigations: MRI is the primary investigative tool, revealing characteristic lesions (plaques) in the white matter.

• Periventricular, juxtacortical, infratentorial and spinal cord lesions are considered typical of MS. The revised McDonald criteria facilitate the diagnosis using MRI, with dissemination in space and time being key factors.
• CSF analysis showing oligoclonal bands supports the diagnosis, although it is not mandatory.

Treatment Management of MS involves acute relapse treatment, disease-modifying therapies (DMTs), and symptom management.

• For acute relapses, short courses of oral high-dose corticosteroids are commonly used.
• DMTs aim to reduce the frequency and severity of relapses and slow disease progression. Choices of DMTs depend on the disease course, severity, and patient factors. First-line treatments often include interferon beta and glatiramer acetate. For more active or progressive disease, options such as natalizumab, fingolimod, or alemtuzumab may be considered, following specialist advice.
• Symptomatic treatments address specific symptoms such as muscle spasticity, neuropathic pain, bladder dysfunction, and fatigue, employing various pharmacological and non-pharmacological interventions.

Prognosis The prognosis of MS is highly variable. Most individuals with RRMS eventually develop secondary progressive MS, characterised by gradual neurological decline without relapses. Life expectancy is somewhat reduced compared to the general population. Early diagnosis and treatment initiation have been associated with better outcomes.