Relapsing catastrophic antiphospholipid antibody syndrome: a mimic for thrombotic thrombocytopenic purpura?

The catastrophic antiphospholipid antibody syndrome (CAPS) is an uncommon d isorder characterized by widespread micro- and macrovascular changes due to intravascular thrombosis. This complication of the antiphospholipid antibo dy syndrome is often fatal and recurrences are very rare. The differential diagnosis of CAPS includes thrombotic thrombocytopenic purpura (TTP) and th is distinction may be difficult, but essential, for appropriate therapy. Pl asmapheresis is effective in both conditions, but anticoagulation, a mainst ay in the treatment of CAPS, could be disastrous in TTP. We present the cas e of an elderly woman who survived two episodes of CAPS four years apart an d whose clinical findings were also suggestive of TTP. The characteristics of TTP and CAPS are compared and the importance of accurate diagnosis is em phasized.