A thrombotic microangiopathy (TMA) occurs when a patient presents with microangiopathic hemolytic anemia, thrombocytopenia and organ damage. There are many causes of TMAs, but thrombotic thrombocytopenic purpura (TTP) must always be considered because of its high mortality rate. Treatment with therapeutic plasma exchange and transfusions can reduce the mortality rate but those treatments carry their own morbidity. Severe cobalamin deficiency can cause a clinical picture similar to TTP. Understanding the pathologic changes of this pseudo-TTP can allow physicians to suspect this difference early in the clinical course. In the following case, elevations in homocysteine and methylmalonic acid, as well as changes in the CBC, allowed this distinction to be identified early, minimizing potentially dangerous treatments.

The authors have no financial disclosures to declare and no conflicts of interest to report.