Review of thrombotic thrombocytopenic purpura in the setting of systemic lupus erythematosus.

OBJECTIVE: Thrombotic thrombocytopenic purpura (TTP) has been described in association with systemic lupus erythematosus (SLE) rarely. The diagnosis of TTP as a process separate from SLE may be difficult because both share similar features, including thrombotic microangiopathy.
METHODS: A case is described of the simultaneous occurrence of TTP and SLE. The clinical, laboratory, and histologic findings of the patient are reported. The association of TTP and SLE in the literature is analyzed. We review separately the pathogenesis, role of antiphospholipid antibodies, and the differential diagnosis of TTP complicating the course of SLE.
RESULTS: Forty cases of TTP in association with SLE are reported in the world literature. Three distinct groups were defined by the presentation of TTP that occurred subsequent to, before, or simultaneous with SLE (groups 1, 2, and 3, respectively). Renal biopsy in a patient with lupus nephritis may reveal thrombotic microangiopathy, which may be seen independently or represent a concomitant systemic thrombotic process such as TTP, disseminated intravascular coagulation, or antiphospholipid antibody syndrome.
CONCLUSION: TTP in association with SLE is rare, and the diagnosis may be challenging. Although the etiology of TTP remains elusive, certain autoimmune mechanisms, platelet abnormalities, and fibrinolytic disorders may be shared with SLE and provide the basis for their association. Management requires timely diagnosis and aggressive treatment by therapeutic plasma exchange.