TABLE 4: The 2010 McDonald Criteria for Diagnosis of MS Polman et al: 2010 Revisions to MS Diagnosis Clinical Presentation 2 attacksa; objective clinical evidence of 2 lesions or objective clinical evidence of 1 lesion with reasonable historical evidence of a prior attackb 2 attacksa; objective clinical evidence of 1 lesion 1 attacka; objective clinical evidence of 2 lesions 1 attacka; objective clinical evidence of 1 lesion (clinically isolated syndrome) Insidious neurological progression suggestive of MS (PPMS) Additional Data Needed for MS Diagnosis Nonec Dissemination in space, demonstrated by: 1 T2 lesion in at least 2 of 4 MS-typical regions of the CNS (periventricular, juxtacortical, infratentorial, or spinal cord)d; or Await a further clinical attacka implicating a different CNS site Dissemination in time, demonstrated by: Simultaneous presence of asymptomatic gadolinium-enhancing and nonenhancing lesions at any time; or A new T2 and/or gadolinium-enhancing lesion(s) on follow-up MRI, irrespective of its timing with reference to a baseline scan; or Await a second clinical attacka Dissemination in space and time, demonstrated by: For DIS: 1 T2 lesion in at least 2 of 4 MS-typical regions of the CNS (periventricular, juxtacortical, infratentorial, or spinal cord)d; or Await a second clinical attacka implicating a different CNS site; and For DIT: Simultaneous presence of asymptomatic gadolinium-enhancing and nonenhancing lesions at any time; or A new T2 and/or gadolinium-enhancing lesion(s) on follow-up MRI, irrespective of its timing with reference to a baseline scan; or Await a second clinical attacka 1 year of disease progression (retrospectively or prospectively determined) plus 2 of 3 of the following criteriad: 1. Evidence for DIS in the brain based on 1 T2 lesions in the MS-characteristic (periventricular, juxtacortical, or infratentorial) regions 2. Evidence for DIS in the spinal cord based on 2 T2 lesions in the cord 3. Positive CSF (isoelectric focusing evidence of oligoclonal bands and/or elevated IgG index) If the Criteria are fulfilled and there is no better explanation for the clinical presentation, the diagnosis is ‘‘MS’’; if suspicious, but the Criteria are not completely met, the diagnosis is ‘‘possible MS’’; if another diagnosis arises during the evaluation that better explains the clinical presentation, then the diagnosis is ‘‘not MS.’’ aAn attack (relapse; exacerbation) is defined as patient-reported or objectively observed events typical of an acute inflammatory demyelinating event in the CNS, current or historical, with duration of at least 24 hours, in the absence of fever or infection. It should be documented by contemporaneous neurological examination, but some historical events with symptoms and evolution characteristic for MS, but for which no objective neurological findings are documented, can provide reasonable evidence of a prior demyelinating event. Reports of paroxysmal symptoms (historical or current) should, however, consist of multiple episodes occur- ring over not less than 24 hours. Before a definite diagnosis of MS can be made, at least 1 attack must be corroborated by findings on neurological examination, visual evoked potential response in patients reporting prior visual disturbance, or MRI consistent with demyelination in the area of the CNS implicated in the historical report of neurological symptoms. bClinical diagnosis based on objective clinical findings for 2 attacks is most secure. Reasonable historical evidence for 1 past attack, in the absence of documented objective neurological findings, can include historical events with symptoms and evolution character- istics for a prior inflammatory demyelinating event; at least 1 attack, however, must be supported by objective findings. cNo additional tests are required. However, it is desirable that any diagnosis of MS be made with access to imaging based on these Criteria. If imaging or other tests (for instance, CSF) are undertaken and are negative, extreme caution needs to be taken before making a diagnosis of MS, and alternative diagnoses must be considered. There must be no better explanation for the clinical pre- sentation, and objective evidence must be present to support a diagnosis of MS. dGadolinium-enhancing lesions are not required; symptomatic lesions are excluded from consideration in subjects with brainstem or spinal cord syndromes. MS ¼ multiple sclerosis; CNS ¼ central nervous system; MRI ¼ magnetic resonance imaging; DIS ¼ dissemination in space; DIT ¼ dissemination in time; PPMS ¼ primary progressive multiple sclerosis; CSF ¼ cerebrospinal fluid; IgG ¼ immunoglobulin G. February 2011 297