Update on antiphospholipid antibody syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by antiphospholipid antibodies (aPL) associated with thrombosis and/or pregnancy morbidity. Most APS events are directly related to thrombotic events, which may affect small, medium or large vessels. Other clinical features like thrombocytopenia, nephropathy, cardiac valve disease, cognitive dysfunction and skin ulcers (called non-criteria manifestations) add significant morbidity to this syndrome and represent clinical situations that are challenging.