Pseudo-thrombotic Microangiopathy - An Unusual Presentation of Cobalamin Deficiency.

Vitamin B12 is a water-soluble vitamin cofactor for many enzymatic reactions in the body. It plays a vital role in the normal maturation of red blood cells and in producing proteins needed for normal neurological function. The most common presentations of vitamin B12 deficiency are hematological abnormalities and neurological manifestations. Pseudo-thrombotic microangiopathy, a syndrome of hemolysis and thrombocytopenia, may mimic the presentation of thrombotic microangiopathies such as thrombotic thrombocytopenic purpura, an uncommon presentation of vitamin B12 deficiency. We present the case of a 58-year-old male with no significant past medical history who presented with severe macrocytic anemia and thrombocytopenia with laboratory findings suggestive of hemolytic anemia. He was found to have vitamin B12 deficiency with positive serological markers suggesting pernicious anemia is the underlying cause. Our case demonstrates that vitamin B12 deficiency should be considered in cases of suspected thrombotic microangiopathy, especially in the setting of significantly elevated lactate dehydrogenase levels and low reticulocyte count to avoid the initiation of unnecessary and expensive treatment modalities such as plasmapheresis.