**2.1.11 Antiphospholipid Syndrome (APS)**

It refers to a syndrome characterized by arterial or venous thrombosis or specific pregnancy complications in women with laboratory evidence of antibodies to proteins bound to anionic phospholipids. International consensus conferences have proposed and revised classification criteria for definite APS ( Sapporo criteria)(Miyakis 2006). Definite APS is considered present if at least one of the following clinical criteria and at least one of the following laboratory criteria are satisfied.


**Clinical manifestations** include deep vein thrombosis, thrombocytopenia, livedo reticularis, stroke, superficial thrombophlebitis, pulmonary embolism, fetal loss, transient ischemic attack, and hemolytic anemia. In rare patients, APS results in multiorgan failure because of multiple blood vessel occlusions, a condition referred to as "catastrophic antiphospholipid syndrome" In patients with preeclampsia or the HELLP syndrome, catastrophic APS must be considered, in patients with histories of thrombosis or spontaneous abortions . Thrombotic renal disease occurs in a minority of patients with APS. Glomerular capillaries and other renal vessels, both arteries and veins of all sizes, can be affected. The disease may be silent or produce acute or chronic renal failure with proteinuria. APLS may cause glomerular lesions like membranous nephropathy, minimal change disease or proliferative glomerulonephritis.
