How does multiple sclerosis (MS) usually present?

Multiple Sclerosis Clinical Presentation

Multiple sclerosis (MS) typically presents in young adults (20-30 years) with unilateral optic neuritis, partial myelitis, sensory disturbances, or brainstem syndromes that develop over several days. 1, 2

Common Initial Presentations

Visual Disturbances

• Optic neuritis occurs in 20-31% of initial MS presentations 1
  • Characterized by:
    • Visual impairment
    • Scotoma (blind spots)
    • Red-green color desaturation
    • Pain with eye movement
  • May lead to optic nerve atrophy in chronic cases

Motor and Sensory Symptoms

• Sensory symptoms:
  • Distal paresthesias
  • Numbness
  • Severe and diffuse pain (may precede weakness) 1
• Motor symptoms:
  • Weakness typically starting in legs and progressing to arms and cranial muscles 3
  • Balance and coordination problems
  • Gait dysfunction (present in 50-80% of patients) 4

Brainstem Manifestations

• Internuclear ophthalmoplegia (failure of ipsilateral eye adduction with contralateral eye abduction nystagmus) 5
• Abnormalities of gaze, saccades, pursuit, and nystagmus 5
• Diplopia (double vision)

Patterns of Presentation

Relapsing-Remitting Pattern

• Most common initial presentation
• Characterized by:
  • Episodes of neurological dysfunction
  • Partial or complete recovery
  • Stable periods between relapses

Progressive Patterns

• Primary progressive: steady neurological decline from onset
• Secondary progressive: initial relapsing-remitting course followed by steady decline

Atypical Presentations

• Asymmetrical weakness (though always bilateral) 3
• Predominantly proximal or distal weakness 3
• Isolated cranial nerve dysfunction 3, 1
• Pure motor or pure sensory variants 3
• In children under 6: nonspecific features including poorly localized pain, refusal to bear weight, irritability, meningism, or unsteady gait 3

Diagnostic Imaging Findings

Brain MRI

• T2-hyperintense lesions that are often:
  • Periventricular
  • Juxtacortical
  • Infratentorial
• May show gadolinium-enhancing lesions 1

Spinal Cord MRI

• Focal lesions with clearly demarcated borders
• Typically small (at least 3mm), covering less than two vertebral segments
• Usually located in the periphery of the spinal cord
• Often in lateral or dorsal columns
• Cigar-shaped on sagittal images and wedge-shaped on axial images 3

Red Flags for Alternative Diagnoses

• Symptoms reaching maximum disability within 24 hours or after 4 weeks 3
• Spinal cord lesions extending over three or more vertebral segments 3
• Prominent involvement of central gray matter 3
• Posterior optic nerve involvement 1
• Simultaneous bilateral optic nerve involvement 1
• Leptomeningeal enhancement 1

Diagnostic Criteria

MS diagnosis requires evidence of:

1. Dissemination in space (damage in different parts of the nervous system)
2. Dissemination in time (damage occurring at different times)
3. No better explanation for the clinical presentation 1

Common Pitfalls in Diagnosis

• Failing to recognize atypical presentations, especially in children
• Misinterpreting normal reflexes in pure motor variants with AMAN subtype 3
• Not considering MS mimics such as neuromyelitis optica, acute disseminated encephalomyelitis, and small vessel disease 1
• Overlooking the possibility of MS in patients with isolated symptoms like fatigue, cognitive changes, or mood disorders 6

Early recognition of MS symptoms is crucial as prompt diagnosis and treatment with disease-modifying therapies can reduce relapse rates by 29-68% compared to placebo or active comparators, potentially slowing disease progression and improving long-term outcomes 1, 2.