This week at morning report, we discussed TTP. Here is how you should think about the management of TTP:
Plasma Exchange: cornerstone of treatment. Perform daily until there is a complete response (see below).
Rituximab: beneficial to start early, there is data that suggests better remission rates when added to plasma exchange upfront.
Steroids: adjunctive because there is minimal data to back this up, but generally recommended if there is no contraindication.
These treatment modalities are initiated early and urgently in a patient with presumptive TTP. Treatment is continued until there is a complete response, which is defined by a platelet count above 150,000 for two consecutive days, together with normal or normalizing LDH and clinical recovery (ie end organ damage has resolved). After treatment, patients are most vulnerable to a recurrence within the first week after tapering of therapy. Patients are followed closely to assess for symptoms and for CBC/ADAMTS13 monitoring. What is unclear is what to do with patients who are asymptomatic but have a down trending/low ADAMTS13. In this situation, data suggests that treatment with rituximab can reduce the possibility of relapse, likely through decreasing the production of the antibodies inhibiting ADAMTS13.