Classification of Sneddon's syndrome

The combination of generalized broken ("racemose") livedo and cerebrovascular accidents is referred to as "Sneddon's syndrome". Although several pathogenetic factors have been suggested the aetiology of Sneddon's syndrome is unknown. Furthermore, considerable variability of patient characteristics gives rise to the question whether "Sneddon's syndrome" denotes a homogeneous disease entity at all. We hypothesized that the diagnosis "Sneddon's syndrome" can be broken down into different subgroups according to possible aetiologic factors.

Thirty-two patients with the combination of generalized broken livedo and cerebrovascular accidents were evaluated by clinical examination, routine diagnostic procedures, MRI of the brain, echocardiography, vascular ultrasound, immunologic and haemostaseologic testing. Patient groups were formed, depending on (1) whether or not an additional feature with a possibly aetiologic role for Sneddon's syndrome was present, and (2) which kind of feature it was.

In 16 out of 32 patients, diagnostic features with an implication for the pathogenesis of Sneddon's syndrome could be identified. An autoimmune disorder was diagnosed in six patients. A thrombophilic state was detected in six patients. Three patients had preexisting atherosclerosis. One patient suffered from an embolizing atrial myxoma. Extent and kind of cerebral pathology differed between patient groups as did the kind of cardiac involvement.

Sneddon's syndrome is not a homogeneous disease entity. Patients should be classified as "primary Sneddon's syndrome" if no aetiologic factor can be detected. On clinical grounds, this from differs from several varieties of "secondary Sneddon's syndrome" which occurs mainly as part of an autoimmune disorder or in a thrombophilic state.