✅ Recent onset of thrombocytopenia and hemolytic anemia is consistent with a diagnosis of Evans syndrome, thrombotic microangiopathies (such as thrombotic thrombocytopenic purpura [TTP], hemolytic uremic syndrome [HUS] or disseminated intravascular coagulation [DIC]), infection or primary bone marrow process such as acute leukemia.
✅ TTP is distinguished from other types of thrombotic microangiopathies by virtue of normal (or near normal) renal function and coagulation assays.
✅ The classic clinical pentad of hemolytic anemia, thrombocytopenia, fever, acute kidney injury, and severe neurologic findings occurs in less than 10% of patients (but is still found on board exams!)
✅ Diagnosis of TTP is:
- Suggested in a patient with isolated microangiopathic hemolytic anemia, thrombocytopenia, and evidence of organ dysfunction, especially brain or heart, and further supported by a high PLASMIC score.
- Confirmed by low ADAMTS13 activity levels (<10%).
✅ Treatment is typically initiated in patients with high pretest probability of having TTP before ADAMTS13 activity levels are known.
✅ First-line therapy for patients who have a high probability of TTP (based on clinical assessment +/- clinical prediction score) consists of plasma exchange and steroids.
✅ Other therapies may be considered, including rituximab and caplacizumab, but these are added to plasma exchange/steroids, rather than replacing them.