When vitamin deficiency mimics thrombotic thrombocytopenic purpura

Microangiopathic haemolytic anaemia with thrombocytopenia induced by vitamin B12 deficiency long term after gastrectomy

Microangiopathic haemolytic anaemia with thrombocytopenia, called pseudo-thrombotic microangiopathy (TMA), is a clinically important complication in patients with vitamin B12 deficiency. We herein present a case of an 80-year-old woman with pseudo-TMA after gastrectomy. She was initially suspected with thrombotic thrombocytopenic purpura based on rapid progression of anaemia with schistocytes and thrombocytopenia; however, her anaemia and thrombocytopenia were improved by vitamin B12 supplementation alone, with a single session of plasma exchange. Vitamin B12 deficiency was finally confirmed by low vitamin B12 levels from the patient's initial blood sample. In addition, normal ADAMTS13 activity was proven, lowering the likelihood of thrombotic thrombocytopenic purpura. Therefore, this patient was diagnosed with pseudo-TMA caused by vitamin B12 deficiency. Pseudo-TMA can occur in patients with vitamin B12 deficiency post-gastrectomy.

Thrombotic Thrombocytopenic Purpura-like Thrombocytopenia Closely Related to Uremia: Report of Two Cases

Idiopathic thrombotic thrombocytopenic purpura (TTP) was suspected in two cases with end-stage renal disease (ESRD) before initiating dialysis based on both the clinical course and the initial laboratory findings. After three plasma exchanges and four sessions of hemodialysis, the thrombocytopenia improved to the normal range. However, the level of haptoglobin remained low after the recovery of platelet count. The low activity of ADAMTS13 (a disintegrin-like and metalloprotease with thrombospodin type 1 repeats) was not observed and the inhibitor was negative in these two cases. Therefore, thrombocytopenia was not attributable to TTP and other factors might therefore be involved in its pathogenesis. Some investigators have reported that a uremic state may possibly be involved in thrombocytopenia in both animals and humans. In the present cases, no apparent cause other than uremia was found because, after initiating hemodialysis, the thrombocytopenia rapidly improved. In conclusion, TTP-like thrombocytopenia can be caused by uremia and the influence of uremia should be considered in the pathogenesis of ESRD patients with TTP-like manifestations.