Red flags and atypical symptoms

"The following study is very timely in view if the recent debate on the diagnosis and misdiagnosis of MS."

Epub ahead of printKelly et al. Using atypical symptoms and red flags to identify non-demyelinating disease. J Neurol Neurosurg Psychiatry. 2011 Aug 17.

Background: Red flags and atypical symptoms have been described as being useful in suggesting alternative diagnoses to MS and clinically isolated syndrome (CIS); however, their diagnostic utility has not been assessed. 

Aim: The aim of this study was to establish the predictive value of red flags and the typicality/atypicality of symptoms at presentation in relation to the final diagnosis of patients referred with suspected MS. 

Methods: All patients referred with suspected MS over a 3-year period were assessed by the typicality of the clinical presentation and the occurrence of red flags in relation to the eventual diagnosis. The extent of agreement of trainee and consultant neurologists as to typicality of clinical presentations was determined. 

Results: Of 244 patients referred, 119 (49%) had MS/CIS and 125 (51%) did not. 41 patients were referred because of an abnormal MRI. Of 203 with clinical symptoms, 96 patients had atypical symptoms of whom, 81 (84%) did not have MS and 15 (16%) had MS/CIS. Typical symptoms occurred in 107 patients; 10% did not have MS/CIS. 

The average percentage agreement between consultants and trainees was 73% with a range of 32-96%.

Conclusions: Atypical features at presentation are more sensitive and specific and have a higher positive predictive value than red flags to refute a diagnosis of MS/CIS.

Q: "What are red flags?"
A: "Red flags are clinical features that alert neurologists to potential other diagnoses and MS mimics."

Q: "What are atypical presentations?"
A: "These are presentations of MS that are rare and are more common with other diseases. For example presenting with a seizure."

"I hope the figures presented in this study highlight the difficulty we have making a diagnosis of MS and that things are not black-and-white." 

"Remember the artist with a palette who paints in various shades gray."