EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is the phenomenon of a spurious low platelet count due to the appearance of antibodies that cause platelet agglutination in blood anticoagulated with EDTA. We review here the clinical features of 18 patients with EDTA-PTCP treated in our hospital from 1984 to 1987 as well as those of 34 patients reported in the literature. This phenomenon appears more frequently in severely ill patients, in association with autoimmune, neoplastic, atherosclerosis-related, and liver diseases. In the majority of our patients, EDTA-PTCP appeared during hospitalization, indicating that the antibody is an acquired one. Neither splenomegaly nor the presence of autoimmune markers were features of this entity. Unlike true thrombocytopenias, EDTA-PTCP is associated with a normal mean platelet volume. Awareness of this entity is essential since EDTA-PTCP is frequently misdiagnosed and therefore incorrectly treated.

According to previous clinical studies, the neurological manifestations observed in patients with thrombotic thrombocytopenic purpura (TTP) are considered to be transient. The introduction of plasma therapy in 1977 as major treatment modality for TTP has changed the prognosis of the disease. In a clinical survey of 38 patients with TTP who received plasma therapy, we have observed five patients who developed permanent neurological deficits despite their prompt recovery from TTP. In this study, we describe the new complication of TTP and summarize the neurological manifestations observed in these patients during their first episode of TTP and during the relapses, which occurred in 12 of them.