VII. TEACHING POINTS

1. In anemic patients, the reticulocyte count allows us to distinguish between mechanisms which are due to decreased bone marrow production and mechanisms which are due to peripheral RBC destruction or acute blood loss. Patients with hemolysis should also demonstrate increased serum LDH and indirect bilirubin. They also will demonstrate a decrease in serum haptoglobin.



2. For thrombocytopenic patients, especially in those who are also anemic, it is critically important to carefully review the peripheral blood smear to assess it for schistocytes as a sign of microangiopathic hemolysis and carefully examine the abdomen for an enlarged spleen. The smear should always be examined before treating thrombocytopenic patients with platelet transfusions because these transfusions may acutely worsen the neurologic signs in TTP.



3. Although there is a pentad of signs and symptoms in TTP, not all patients will demonstrate all five at the time of presentation. TTP remains a clinical diagnosis, and because of the extremely high case fatality rate, it is an emergency for which prompt plasma treatment is essential.



4. Plasma therapy, i.e., plasma infusion followed by daily plasma exchange, is the treatment of choice for TTP, and patients should be started on treatment immediately. Approximately 80% of patients respond to initial treatment. Then, they may be “cured,” may relapse years later, or may have a chronic relapsing course.



5. In some patients, the TTP may be associated with other underlying conditions, including HIV, SLE, chemotherapeutic drugs, and bone marrow transplantation.