American Journal of Medical Case Reports
ISSN (Print): 2374-2151 ISSN (Online): 2374-216X Website: Editor-in-chief: Samy, I. McFarlane
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American Journal of Medical Case Reports. 2021, 9(11), 532-534
DOI: 10.12691/ajmcr-9-11-3
Open AccessCase Report

Life-threatening Pseudo-thrombotic Microangiopathy Caused by Severe Vitamin B12 Deficiency

Ziad Abuhelwa1, , Talal Khan2, Rana Daas3, Sami Ghazaleh1 and Ragheb Assaly1

1Department of Internal Medicine, University of Toledo College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio 43606

2Department of Hemato-Oncology, University of Toledo College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio 43606

3University of Toledo College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio 43606

Pub. Date: July 11, 2021

Cite this paper:
Ziad Abuhelwa, Talal Khan, Rana Daas, Sami Ghazaleh and Ragheb Assaly. Life-threatening Pseudo-thrombotic Microangiopathy Caused by Severe Vitamin B12 Deficiency. American Journal of Medical Case Reports. 2021; 9(11):532-534. doi: 10.12691/ajmcr-9-11-3


Vitamin B12 deficiency is a common cause of macrocytic anemia. Life-threatening hematologic complications including immune and non-immune hemolytic anemia are present in about 10% of the cases. Pseudo-thrombotic microangiopathy is an extremely rare presentation found in around 2.5% of patients with vitamin B12 deficiency. We present a case of a 70-year-old male patient who presented with progressive fatigue and syncope. He was found to severe macrocytic anemia with hemoglobin of 4.1 g/dL. Further workup showed very low serum vitamin B12 level at 22 pg/mL (normal 180-914), methylmalonic acid of 93.23 umol/L (normal 0-0.4) and homocysteine of 93 umol/L (normal 4-12). Anti-parietal cell and intrinsic factor blocking antibodies were positive. He was noted as well to have thrombocytopenia, low haptoglobin, increased lactate dehydrogenase and increased serum creatinine. Peripheral blood smear showed schistocytes, hyper-segmented neutrophils, and marked dimorphic anemia. His presentation was concerning for thrombotic thrombocytopenic purpura; however, PLASMIC score was intermediate. He was monitored in the intensive care unit. He received supportive treatment with intravenous hydration and packed red blood cells transfusion. He was started on daily intramuscular cyanocobalamin supplements. Significant improvement in his symptoms with near normalization of complete blood count after one month of treatment was noted. His condition improved without the need for plasmapheresis.

hemolysis Vitamin B12 anemia autoimmunity

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[1]  Nagao, T. and M. Hirokawa, Diagnosis and treatment of macrocytic anemias in adults. J Gen Fam Med, 2017. 18(5): p. 200-204.
[2]  Andrès, E., et al., Pseudo-thrombotic microangiopathy related to cobalamin deficiency. Am J Med, 2006. 119(12): p. e3.
[3]  George, J.N. and C.M. Nester, Syndromes of Thrombotic Microangiopathy. New England Journal of Medicine, 2014. 371(7): p. 654-666.
[4]  Langan, R.C. and A.J. Goodbred, Vitamin B12 Deficiency: Recognition and Management. Am Fam Physician, 2017. 96(6): p. 384-389.
[5]  Dalsania, C.J., et al., A sheep in wolf's clothing. Am J Med, 2008. 121(2): p. 107-9.
[6]  Acharya, U., et al., Hemolysis and hyperhomocysteinemia caused by cobalamin deficiency: three case reports and review of the literature. Journal of hematology & oncology, 2008. 1: p. 26-26.
[7]  Hunt, A., D. Harrington, and S. Robinson, Vitamin B12 deficiency. Bmj, 2014. 349: p. g5226.
[8]  Malek, A. and R. Nasnas, An Unusual Presentation of Pseudothrombotic Microangiopathy in a Patient with Autoimmune Atrophic Gastritis. Case Reports in Hematology, 2016. 2016: p. 1087831.
[9]  Buess, C.S., et al., Vitamin B12 Deficiency with Pseudothrombotic Microangiopathy and Thrombotic Thrombocytopenic Purpura: Similarities and Differences. Kans J Med, 2020. 13: p. 46-48.
[10]  Ventura, P., et al., A role for homocysteine increase in haemolysis of megaloblastic anaemias due to vitamin B(12) and folate deficiency: results from an in vitro experience. Biochim Biophys Acta, 2004. 1739(1): p. 33-42.
[11]  Van Hove, J.L., et al., Cobalamin disorder Cbl-C presenting with late-onset thrombotic microangiopathy. Am J Med Genet, 2002. 111(2): p. 195-201.
[12]  Li, A., et al., External validation of the PLASMIC score: a clinical prediction tool for thrombotic thrombocytopenic purpura diagnosis and treatment. J Thromb Haemost, 2018. 16(1): p. 164-169.
[13]  Bendapudi, P.K., et al., Derivation and external validation of the PLASMIC score for rapid assessment of adults with thrombotic microangiopathies: a cohort study. Lancet Haematol, 2017. 4(4): p. e157-e164.
[14]  Som, S., et al., Decreasing frequency of plasma exchange complications in patients treated for thrombotic thrombocytopenic purpura-hemolytic uremic syndrome, 1996 to 2011. Transfusion, 2012. 52(12): p. 2525-32; quiz 2524.
[15]  Walter, K., J. Vaughn, and D. Martin, Therapeutic dilemma in the management of a patient with the clinical picture of TTP and severe B12 deficiency. BMC Hematol, 2015. 15: p. 16.
[16]  d'Onofrio, G., et al., Reticulocytes in haematological disorders. Clin Lab Haematol, 1996. 18 Suppl 1: p. 29-34.
[17]  Garderet, L., et al., Schizocytosis in pernicious anemia mimicking thrombotic thrombocytopenic purpura. Am J Med, 2003. 114(5): p. 423-5.
[18]  Vanoli, J., et al., Vitamin B12 deficiency-induced pseudothrombotic microangiopathy without macrocytosis presenting with acute renal failure: a case report. Journal of Medical Case Reports, 2018. 12(1): p. 296.