Features of Sneddon system:
(1) cerebrovascular accident
(2) generalized, racemose (broken) livedo reticularis
Secondary causes:
(1) autoimmune disease
(2) thrombophilic/hypercoagulable state (congenital deficiencies of Protein S, Protein C, etc)
(3) atherosclerosis
(4) atrial myxoma with embolization
If no secondary cause is found after a complete workup, then it is classified as primary.
Conditions in autoimmune disease that might contribute to the condition:
(1) antiphospholipid antibody syndrome (see Chapter 4), which is also a thrombophilic state
(2) cryoglobulinemia
(3) vasculitis
Correct classification is dependent on the completeness of the diagnostic workup:
(1) looking for a history suggestive of the antiphospholipid antibody syndrome or hypercoagulable state (including early age at onset, family history, etc)
(2) thorough workup for antiphospholipid antibodies (lupus anticoagulant, antiphospholipid antibodies IgM and IgG, anti-beta-2-glycoprotein antibodies IgM and IgG)
(3) thorough workup for conditions associated with hypercoagulability
(4) echocardiography of the heart
