Head of Lupus Research Unit
The Rayne Institute
St. Thomas' Hospital, London SE1 7EH
(First printed in: LUPUS (1999), Volume 8 Number 2)
(Full references have been omitted and the reader should refer to the above journal or to Stockton Press).
The issue of "Lupus" includes a further study embracing "multiple sclerosis" (MS) or "atypical MS" in the clinical spectrum covered by the antiphospholipid syndrome (APS).
As IJdo et al (1998) pointed out in their paper, "with increasing utilisation of MRI studies, there has been a marked increased incidence in the misdiagnosis of MS in the American population". An observation which can probably be applied elsewhere.
One of the different diagnosis of MS is APS. from the first clinical descriptions, it was obvious that neurological features were both frequent and protean. Spinal cord involvement has included Guillain-Barre syndrome and transverse myelitis. Anecdotally, most clinicians dealing with APS or lupus with APS have seen patients initally labelled as "probable MS". Certainly the ischaemic changes produced by the APS in the white matter may be indistinguishable on MRI from those of MS. Conversely, it may be that some patients with "true" MS occasionally exhibit anticardiolipin (aCL) antibodies.
Fukazawa et al (1993) found that 2 out of 38 patients with definite MS had positive aCL titres. Both of these patients had optic neuritis and transverse myelitis. A subsequent study reported positive aCL (IgG 9% and IgM 44%) in 32 MS patients. Another study from Japan reviewed 20 cases of MS, all of whom had optic neuritis. No less that 9 had transverse mylelitis. Four patients (all of whom had optic neuritis and myelitis) were positive for aCL. In a small study in our department, sera from 36 MS patients were studied. Five were aPL positive and of these, two had transverse myelitis (unpublished observations).
In the series of patients from the USA reported in this issue of LUPUS, 8% of a cohort of patients with aPL-related symptoms carried a diagnosis of MS or MS-like disease. Blinded MRI lesions were consistent with MS in the majority of cases. Of the 26 patients with an MS diagnosis, seven had transverse myelitis and eight had optic neuritis.
Therefore, a theme might be developing that the presence of transverse myletis - long suspected to be associated with aPL, might be a pointer towards this differential diagnosis.
That the label "MS" involves a mixed group of disorders comes as no surprise to physicians. For the patients, the importance of a treatable differential diagnosis - APS - cannot be understated.