Multiple Sclerosis

Key Features

Essentials of Diagnosis

• Episodic neurologic symptoms

• Onset: usually under 55 years of age

• Single pathologic lesion cannot explain clinical findings

• Multiple foci best visualized by MRI

General Considerations

• Should not be diagnosed unless there is evidence that two or more different regions of the central white matter (dissemination in space) have been affected at different times (dissemination in time)

• Diagnosis may be made in a patient with two or more typical attacks and

  • Objective evidence on clinical examination of two lesions (eg, optic disk atrophy and pyramidal weakness) or

  • Objective evidence of one lesion with clear-cut historical evidence the other attack was typical of multiple sclerosis and in a distinct neuroanatomic location

• To fulfill the criterion of dissemination in space in a patient with only one lesion

  • Repeat imaging in a few months; at least one lesion should be demonstrated in at least two of four typical sites

    • Periventricular

    • Cortical or juxtacortical

    • Infratentorial

    • Spinal

  • Alternatively, another attack localized to a different site suffices

• To fulfill the criterion of dissemination in time in a patient with only one attack

  • Simultaneous presence of gadolinium-enhancing and nonenhancing lesions at any time (including at initial examination)

  • Presence of oligoclonal bands unique to the cerebrospinal fluid

  • A new lesion on follow-up MRI

  • A second attack

• Primary progressive disease requires at least a year of progressive disease, plus two of three of the following:

  • At least one typical brain lesion

  • At least two spinal lesions

  • Oligoclonal banding in the cerebrospinal fluid

• In patients with a single clinical event who do not satisfy criteria for multiple sclerosis, a diagnosis of a clinically isolated syndrome is made

• Vitamin D deficiency may be associated with an increased risk of developing multiple sclerosis; randomized trials have not shown vitamin D supplementation reduces attack rate or progression in relapsing-remitting disease

Demographics

• Common disorder, probably on an autoimmune basis, with its greatest incidence in young adults

• Much more common in persons of western European lineage who live in temperate zones

• No population with a high risk for multiple sclerosis exists between latitudes 40°N and 40°S

• Nevertheless, a genetic susceptibility to the disease is likely, based on twin studies, familial cases, and an association with specific HLA antigens (HLA-DR2)

Clinical Findings

Symptoms and Signs

• Fatigue is common in all forms of the disease

• Common initial presentation

  • Weakness, numbness, tingling, or unsteadiness in a limb

  • Spastic paraparesis

  • Retrobulbar optic neuritis

  • Diplopia

  • Dysequilibrium

  • Sphincter disturbance, such as urinary urgency or hesitancy

• Symptoms may disappear after a few days or weeks, although examination often reveals a residual deficit

RELAPSING-REMITTING DISEASE

• Symptoms occur months or years after initial presentation

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