Multiple Sclerosis
Autoimmune demyelination — disease-modifying therapy and relapse management
Multiple sclerosis (MS) is a chronic, immune-mediated demyelinating disease of the central nervous system affecting over 130,000 people in the UK. It is the leading cause of neurological disability in young adults, typically presenting between the ages of 20 and 40, and is twice as common in women. While there is no cure, disease-modifying therapies can significantly reduce relapse rates and slow disability progression.
What is Multiple Sclerosis?
MS is caused by immune-mediated inflammation that leads to demyelination (destruction of the myelin sheath surrounding axons) and axonal damage within the CNS. Demyelination impairs or blocks nerve signal conduction, causing the diverse neurological symptoms of MS. Inflammation is predominantly T-cell mediated, with B cells also playing an important role. The cause of MS is multifactorial — genetic susceptibility (HLA-DRB1 allele), environmental factors (low vitamin D, Epstein-Barr virus infection, smoking, northern latitude), and immune dysregulation all contribute. Diagnosis and management are guided by NICE NG220 (2022) and the McDonald diagnostic criteria.
Types of MS
Relapsing-Remitting MS (RRMS) is the most common form (85% at diagnosis), characterised by discrete relapses followed by complete or partial recovery. Secondary Progressive MS (SPMS) develops in many people with RRMS over time — characterised by gradual worsening with or without relapses. Primary Progressive MS (PPMS) affects around 10–15% of people and is characterised by gradual neurological decline from onset without distinct relapses — typically presents in those aged 40–60 and is more common in men. Progressive Relapsing MS (PRMS) is a rare subtype with progressive decline plus acute relapses. A clinically isolated syndrome (CIS) — a first episode of neurological symptoms suggestive of MS — may or may not progress to MS. A radiologically isolated syndrome (RIS) involves MRI abnormalities consistent with MS without clinical symptoms.
Diagnosis (McDonald Criteria)
The 2017 McDonald criteria require demonstration of dissemination of lesions in space (DIS) and time (DIT) in the CNS. MRI of the brain and spine is central to diagnosis — T2/FLAIR lesions in periventricular, juxtacortical, infratentorial and spinal cord locations are characteristic. Gadolinium-enhancing lesions indicate active inflammation. CSF analysis may show oligoclonal bands (OCBs) — immunoglobulins not present in serum — which support the diagnosis. Visual evoked potentials (VEPs) can detect subclinical optic neuritis. Neurological assessment at diagnosis includes the Expanded Disability Status Scale (EDSS). Alternative diagnoses must be excluded — including vasculitis, neuromyelitis optica (NMO — anti-AQP4 antibody positive), sarcoidosis and CNS lymphoma.
Symptom Management
MS causes a wide range of disabling symptoms requiring multidisciplinary management. Evaluation of symptom burden at each clinic visit guides treatment priorities and support planning. Fatigue — the most common and disabling symptom — is managed with pacing, activity management, amantadine 100mg BD, and referral to occupational therapy. Spasticity is treated with baclofen, tizanidine or gabapentin; severe spasticity may warrant intrathecal baclofen. Bladder dysfunction (urgency, frequency, incontinence, retention) is assessed with bladder diary and urodynamics — treated with mirabegron, solifenacin or intermittent self-catheterisation. Bowel problems include constipation and faecal urgency. Pain is common — neuropathic pain is treated with amitriptyline, duloxetine, pregabalin or gabapentin. Depression is managed with SSRIs and psychological therapy. Tremor and cerebellar symptoms are often difficult to treat — propranolol may help. Cognitive impairment affects up to 65% of people with MS — cognitive rehabilitation and employment support are important.