Molecular Mimicry: An Uncommon Occurrence of Vitamin B12 Deficiency Imitating Thrombotic Thrombocytopenic Purpura in an African American Male.

Thrombotic thrombocytopenic purpura (TTP) and vitamin B12 deficiency can share similar symptoms but require different treatment approaches. TTP is a blood disorder with a high mortality rate requiring immediate plasmapheresis treatment. On the other hand, vitamin B12 deficiency usually presents with anemia, low platelet counts, jaundice, and signs of disrupted red blood cell breakdown, resembling a condition called microangiopathic hemolytic anemia. Vitamin B12 deficiency can sometimes lead to or mimic pseudo-thrombotic microangiopathy (pseudo-TMA), a rare occurrence. Pseudo-TMA manifests as microangiopathic hemolytic anemia and thrombocytopenia and is characterized by schistocytes in a peripheral blood smear. Differentiating TTP cases from pseudo-TMA cases is essential and should be done promptly. The etiology, treatments, and prognosis of these two conditions differ and can be fatal if not identified and managed. We present a case that emphasizes the need for familiarity with TTP-like conditions, the use of ADAMTS13 as a diagnostic tool, prompt and accurate treatment decision-making, the complexities of therapeutic plasma exchange, and the importance of excluding an enzyme inhibitor or mutator as the cause of TTP or TTP-like cases. Lack of knowledge can lead to erroneous diagnoses, resulting in unnecessary treatments or delayed life-saving interventions.