From the Research
In Thrombotic Thrombocytopenic Purpura (TTP), the platelet count is severely decreased, typically below 20,000 platelets per microliter of blood, though it can range from 5,000 to 30,000 platelets/μL, as supported by the most recent study 1. This profound thrombocytopenia is a hallmark feature of TTP and contributes to the bleeding manifestations seen in affected patients. The low platelet count occurs because platelets are consumed in the formation of microthrombi throughout the body's small blood vessels. The platelet count is an important diagnostic and monitoring parameter in TTP, with rising platelet counts typically indicating response to treatment. Some studies have shown that the platelet count can be used to predict the response to treatment, with a higher platelet count recovery rate indicating a better prognosis 2. However, other studies have found that the presence of residual schistocytosis, or the presence of schistocytes in the blood, is not predictive of relapse 3. In terms of treatment, daily plasma exchange is typically continued until the platelet count is greater than 150 × 10^3 /µL and the lactate dehydrogenase is near normal for 2-3 consecutive days 1. It is also important to recognize the pseudo-refractory state, where the platelet count plateaus between 100 and 150 x 10^9/L, and to discontinue plasma exchange when this occurs 4. Overall, the management of TTP requires careful monitoring of the platelet count and other laboratory parameters, as well as prompt treatment with plasma exchange and other therapies as needed. In critically ill adults, unresponsive TTP is associated with high morbidity and mortality rates, and early specific treatments are needed to improve outcomes 5. The most important factor in determining the platelet count in TTP is the severity of the disease, with more severe cases typically having lower platelet counts, as shown in the study by 1.