Highlights from

AAN 2019

American Academy of Neurology annual meeting

Philadelphia, USA 4-10 May 2019

McDonald criteria MS often misapplied and misunderstood

Neurology residents and, to a lesser degree, MS specialists from the USA and Canada often incorrectly apply core components of the McDonald diagnostic criteria for MS [1]. The researchers suggest education may reduce misdiagnosis by concentrating on misinterpreted and misapplied components of the criteria.

A number of studies have suggested that MS misdiagnosis may be caused by knowledge gaps for identification of typical MS syndromes, periventricular and juxtacortical MRI lesion locations, and consideration of historical symptoms. US researchers therefore designed a web-based survey to test this knowledge and invited neurology residents and practicing MS specialists by email. In all, 72 residents and 88 MS specialists from the USA and Canada participated.

MS atypical syndromes that were incorrectly identified as typical by residents and MS specialists, respectively:

  • complete transverse myelopathy (by 35% and 15%);
  • intractable vomiting/nausea/hiccups (20% and 5%);
  • bilateral optic neuritis/unilateral optic neuritis with poor visual recovery (17% and 10%).

“Touch or abutting” the ventricle criterion for periventricular lesions was correctly identified by 38% of residents and 61% of MS specialists; “juxtacortical” by 19% and 54%. Optic nerve involvement was incorrectly seen as a region that fulfils the criterion of MRI dissemination in space (DIS) by 31% of residents and 26% of MS specialists. Subcortical white matter was incorrectly identified as a region that fulfils MRI DIS by 11% and 18%. A case of radiologically isolated syndrome was incorrectly identified as justifying the diagnosis MS by 48% and 12%. Nonspecific historical visual symptoms were incorrectly seen as fulfilling the criterion of dissemination in time (DIT) by 75% of residents and 49% of MS specialists. Non-specific historical sensory and coordination symptoms were considered to fulfil DIT by 88% and 65%.

In an editorial comment [2], Dr Wallace Brownlee (University College London, UK) pointed out that an MS diagnosis not only requires the demonstration of lesions disseminated in time and space, but also a requirement for “no better explanation”. This represents a substantial challenge given the varied clinical manifestations of MS, and the absence of a diagnostic test that readily distinguishes MS from other disorders.

  1. Solomon A, et al. AAN 2019, S6.001.
  2. Brownlee WJ. Neurology. 2019 May 1. pii: 10.1212/WNL.0000000000007566.

Top image: © iStockPhoto: Eraxion

The content and interpretation of these conference highlights are the views and comments of the speakers/authors.