14B. Diagnosis of multiple sclerosis

Definition and epidemiology

The diagnosis of multiple sclerosis is based on the so-called McDonald criteria. They require the patient to have evidence of lesions in the CNS in different places and at different times. This is called “dissemination in space and time”.

In some patients, the diagnosis can be made after a single attack, if they have evidence of dissemination in both space and time. If the diagnosis cannot be made (yet) after a single attack that attack is known as a “clinically isolated syndrome” (CIS). However, in most patients the diagnosis is made after the patient has had multiple attacks.

Many modalities are used in the diagnosis:

  • MRI with and without gadolinium contrast – shows demyelinating lesions in predilected areas
    • Periventricular white matter, corpus callosum, spinal cord, cerebellum
  • Lumbar puncture – shows oligoclonal bands in CSF
  • Visually evoked potentials (VEP) – shows slowed optic nerve conduction
  • Motor evoked potentials (MEP) – shows dysfunction of pyramidal tract

Dissemination in space

Dissemination in space is evidenced when either of the following apply:

  • Lesions on MRI in two MS-typical regions in the CNS
  • Clinical features which suggest lesions in multiple sites in the CNS

Dissemination in time

Dissemination in time is evidenced when either of the following apply:

  • Development of an additional clinical attack
    • (Development of a new relapse after a remission)
  • Presence of both gadolinium-enhancing and non-enhancing lesions on a gadolinium contrast MRI
    • Gadolinium-enhancing lesions are maximum a few weeks old, while non-enhancing lesions are older than that
  • Presence of a new gadolinium-enhancing lesion on a follow-up contrast MRI
  • (Presence of oligoclonal bands in CSF can act as a substitute for dissemination in time)

Differential diagnosis

  • Neuromyelitis optica
  • Systemic lupus erythematosus
  • Sarcoidosis
  • Behcet disease
  • Neuroborreliosis
  • Neurosyphilis

Neuromyelitis optica has similar symptoms as MS but worse prognosis and different treatment, so important to distinguish them. NMOD has normal brain MRI, no oligoclonal bands, etc.


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14A. Motor neuron diseases

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15A. Trigeminal neuralgia

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