Primary, Secondary, Catastrophic Antiphospholipid Syndrome: is there a difference?

Following broad recognition of the disorder called Antiphospholipid Syndrome (APS), it has come to be subcategorized into Primary (PAPS), Secondary (SAPS), and Catastrophic Antiphospholipid Syndrome (CAPS). Primary utilized when there is no associated disorder, secondary with an associated autoimmune disorder such as systemic lupus erythematosus (SLE), and "catastrophic" when thrombosis occurs at multiple sites in a short space of time. Are these entities different? Such differences should be demonstrated in terms of their clinical presentation, disease course, pathogenesis, or management. If no differences exist, is there a basis for continued use of these terms? This manuscript will attempt to explore distinctions between subgroups of the APS and reasons for or against perpetuation of these classifications in the literature.