Rheumatology Research Group, University of Liverpool, University Hospital Aintree, Longmoor Lane, Liverpool L9 7AL and
1 Department of Neurology, Walton Neurosciences Centre, Liverpool, UK
Sir, We read with interest the letter of Giorgi et al. [1], concerning the co-existence of Devic's neuromyelitis optica (DNO) and systemic lupus erythematosus (SLE). The authors suggested that DNO was associated with SLE and cited reports of 21 patients with such an association from 1973 to 1997. Although many cases of DNO have been described in SLE, there have been several patients in which DNO appears to be isolated, or perhaps primary. DNO has traditionally been considered to be a subgroup of multiple sclerosis (MS) with optic neuritis (invariably causing residual visual impairment) and transverse myelitis, with no other clinical features to suggest MS. This group of isolated DNO is of particular interest and deserves special mention. We propose that isolated DNO is an autoimmune disease in its own right. The co-existence of two autoimmune diseases is well known. In this context alone, one might expect SLE and DNO to occur together. A review of reported cases of DNO reveals many features of an autoimmune disease, including a striking female to male predominance (24:1), an association with pregnancy [2] and livedo reticularis [3]. Cuadrado et al. [4] have described a subgroup of patients with the anti-phospholipid syndrome with neurological symptoms and magnetic resonance imaging (MRI) findings compatible with MS. In this series of 23 patients, five patients had transverse myelitis and six optic neuritis.
There have only been three reviews of the clinical features of DNO recorded in the literature. In a series of 12 patients with DNO, O'Riordan et al. [3] observed as many as 75% to be autoantibody positive. In a clinicopathological study of eight patients with DNO Mandler et al. [5] observed a severe necrotizing myelopathy with thickening of blood vessel walls and no lymphocyte infiltrates, in contrast to the demyelinating process seen in MS, further distinguishing the pathological processes in these two diseases. In a further series, Mandler et al. [6] reported seven patients with DNO, of which 70% had a positive family history of an autoimmune disorder such as SLE, rheumatoid arthritis or autoimmune thyroiditis. The clinical features and demographic details of the patients described in these three reviews are presented in Table 1.
|
We believe that in some cases primary DNO is being misdiagnosed as the more common MS. The response of DNO to immunosuppressive therapy [6], also pointing to a potential autoimmune aetiology, emphasizes the importance of separating this diagnosis from MS.
Notes
3 Correspondence to: R. J. Moots.
References