Primary antiphospholipid syndrome progressing to systemic lupus erythematosus: a case report

Introduction: Primary antiphospholipid syndrome (APS) is a thrombophilic disease that should be suspected in the presence of thrombotic events associated with hematologic abnormalities such as thrombocytopenia and prolongation of the activated partial thromboplastin time. The diagnosis must be confirmed by the demonstration of autoantibodies directed against anionic phospholipids and/or phospholipid-binding proteins. The disease can cause arterial thrombosis in any vascular district, including those of the kidney and central nervous system.
Case report: In 2006 a 29-year-old male presented with kidney and brain involvement that was attributed to primary APS. The clinical diagnosis was confirmed by the results of a renal biopsy, which excluded the presence of systemic lupus erythematosus (SLE). The patient remained stable through 32 months of follow-up and then developed a malar rash with deteriorating renal function, decreasing platelet count, and reduced complement levels. Serological studies revealed positivity for ANA (homogeneous pattern), dsDNA, ACA, and beta-2-glycoprotein-1 antibodies. The diagnosis was revised to APS secondary to SLE.
Conclusions: A diagnosis of primary APS should not be considered permanent: progression to SLE can occur, in some cases years after the original diagnosis. This case highlights the importance of ongoing follow-up of patients diagnosed with primary APS to detect changes that herald the emergence of SLE.