Secondary Antiphospholipid Syndrome

Abstract

Secondary antiphospholipid syndrome (SAPS) is APS that occurs in the context of another medical condition. Although antiphospholipid antibodies (aPL) can occur in patients with viral, bacterial, or protozoal infections, they are rarely associated with thrombosis. An exception is catastrophic antiphospholipid syndrome which, although extremely rare in itself, is precipitated by infection in a quarter of the cases where a specific trigger can be identified. Antiphospholipid antibodies are also found in patients with malignancy and who are taking certain drugs, but very few of these patients develop SAPS. The majority of SAPS cases occur in association with systemic lupus erythematosus (SLE). In fact many authors now prefer the term SLE-associated APS. Estimates for how commonly this combination occurs vary widely, but aPL occur in up to 30–40 % of patients with SLE, and 30–70 % of these aPL-positive patients may develop APS. The clinical features and management of SLE-associated APS are similar to those of primary APS though some symptoms such as arthritis are more common in the SLE-associated form. It can sometimes be difficult to work out whether the clinical manifestations in an individual patient with SLE-associated APS are due to inflammation or thrombosis.