Vitamin B12 has an important role in DNA synthesis, erythrocyte development and neurological functions by the transfer of one-carbon methyl groups. Vitamin B 12 deficiency may mimic Thrombotic Microangiopathy (TMA) and lead to pseudo-thrombotic microangiopathy (pseudo-TMA). Early recognition of pseudo-TMA is important because treatment with vitamin B 12 replacement is quite simple and effective.

A 66-year-old female patient was admitted to the emergency department with complaints of fatigue. CBC values Hb 3.8gr/dL , Hct 11.3%, MCV 115 fL , platelets 19000/mm³, WBC 6400/mm³, ind.bil.1.5 mg/dL, LDH 2111U/L . In peripheral blood smear (PBS), macroovalocytes, anisopoikilocytes, schistocytes, hypersegmented neutrophils and a normoblast with megaloblastic features (figure-1) were observed. Thrombocytopenia and the presence of schistocyte initially supported TMA.

Blood was drawn from the patient for the ADAMTS-13 test. While concurrent steroid treatment with fresh frozen plasma (FFP) was started, plasmapheresis preparation was also made. The patient's vitamin B12 level was 50 pg/mLThe patient was started on vitamin B12 as 1000 mcg IM. Following clinical recovery, hemoglobin and platelets stabilized, the hemolysis panel indicated a steady improvement (graphs 1, 2, 3).

Results

TMA symptoms can be mimicked by severe vitamin B12 deficiency. Rapid and accurate diagnosis of pseudo-TMA and initiation of parenteral vitamin B 12 replacement can prevent unnecessary and expensive diagnostic investigations and long-term plasma exchange treatments. Our case, has demonstrated the importance of considering vitamin B12 insufficiency in cases presenting with TMA and the value of carefully examining PBS in the identification of megaloblastic anemia.