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I was interested to read the article by Hughes on the antiphospholipid syndrome.1 I agree that primary antiphospholipid syndrome (APS) is a major neurological disease. Disease conditions other than deep vein thrombosis, recurrent fetal loss, or stroke may occur, not only in association with defined systemic lupus erythematosus or “lupus-like” disease, but also with “primary” APS.
Asherson and Cervera included Sneddon’s syndrome (cerebrovascular disease with livedo reticularis) in the category of “primary” APS in their review of the disease.2 Sneddon’s syndrome comprises about 0.26% of total cerebrovascular cases. The pathogenesis of the syndrome has remained largely unclear since its description in 1965.3 Clearly, no immunological testing to detect antiphospholipid antibodies in Sneddon’s original patients was undertaken. Sneddon speculated that skin biopsies in future cases would show endarteritis obliterans in dermal arterioles. It was thought that intravascular pathology of a similar nature was responsible for cerebrovascular accidents. There was no serological evidence of systemic lupus erythematosus or other systemic disorders in most reported cases of classical Sneddon’s syndrome. None of these studies, however, included specific tests for antiphopholipid antibodies or lupus anticagulant.3
In a recently reported case of Sneddon’s syndrome, repeated attempts to detect anticardiolipin antibodies failed to give a positive result.4 But in another study of 10 cases of Sneddon’s syndrome, seven had systemic lupus erythematosus, five were positive for the Venereal Disease Research Laboratory (VDRL) test, and were also positive for lupus anticoagulant.5 Six of these cases had livedo reticularis, all had digital gangrene, cutaneous ulcers, and superficial thrombophlebitis; two had pulmonary embolism. There is little doubt that these cases belonged to the category of “primary” APS, with or without systemic lupus erythematosus.
As the full impact of the APS on neurology is now becoming more widely recognised, I congratulate the author’s attempt to highlight the broad spectrum of the neurological conditions in APS, but also suggest that Sneddon’s syndrome is included.