Vitamin B12 deficiency presenting as pseudo-thrombotic microangiopathy: a case report and literature review

Vitamin B12 Deficiency in Thrombotic Thrombocytopenic Purpura-Like Cases

Background

Thrombotic microangiopathies (TMA) are characterized by a triad of microangiopathic hemolytic anemia, thrombocytopenia, and organ damage which occur in the setting of endothelial damage and platelet activation. Vitamin B12 (cobalamin) deficiency could lead to a picture that resembles TMA, termed metabolic mediated TMA (MM-TMA).

Case Presentation

A 60-year-old female was brought to the hospital after she was found unresponsive. On presentation, she was pale, lethargic, tachycardic, and febrile. Laboratory investigations revealed normocytic anemia, thrombocytopenia, and elevated bilirubin. Blood smear revealed schistocytes and tear drop cells. Given the presence of hemolytic anemia, thrombocytopenia, acute renal failure, and altered mental status, a presumptive diagnosis of thrombotic thrombocytopenic purpura (TTP) was made with a PLASMIC score of 7 indicating high risk. She received plasma exchange, caplacizumab, and intravenous methylprednisolone. Given the patient's low level of vitamin B12, she was initiated on intramuscular cyanocobalamin 1000 μg daily. The encephalopathy resolved and renal function improved. On day 6, ADAMTS13 activity was normal ruling out the diagnosis of TTP. Accordingly, plasmapheresis, steroids, and caplacizumab were discontinued. With continued aggressive B12 replacement, hemolysis resolved indicating severe vitamin B12 deficiency was the likely culprit of this patient's microangiopathic hemolytic anemia.

Conclusion

This case serves to highlight the variable presentation of vitamin B12 deficiency. Severe vitamin B12 deficiency can even mimic TTP. If patients have markers of hemolysis, a low vitamin B12 level, and low reticulocyte count we should consider vitamin B12 deficiency as a likely cause of microangiopathic hemolytic anemia as early detection allows for early initiation of appropriate management.

LEARNING POINTS

Vitamin B12 deficiency can be a cause of thrombotic microangiopathy.

Pernicious Anemia Unveiled: Unusual Hemolytic Complications and Clinical Implications

Pernicious anemia (PA) is an autoimmune condition resulting in impaired vitamin B12 absorption that commonly presents with gastritis and neurological symptoms. In rare cases, associated vitamin B12 deficiency can contribute to significant red blood cell lysis, and patients can present with PA-induced pseudo-thrombotic microangiopathy (TMA) hemolytic anemia. This case describes a 59-year-old male presenting with a two-week history of gastrointestinal pain with bleeding who had anemia and hemodynamic instability on initial evaluation. After the endoscopy/colonoscopy did not reveal any active sources of bleeding and packed red blood cells failed to stabilize the patient, it was found that he had low serum B12 with anti-intrinsic factor and anti-parietal cell antibodies. A coordinated clinical approach, including parenteral cyanocobalamin and daily oral folic acid supplementation, stabilized the patient, highlighting the importance of distinguishing PA-induced pseudo-TMA from true TMA hemolytic anemia.

Adult Vitamin B12 Deficiency-Associated Pseudo-Thrombotic Microangiopathy: A Systematic Review of Case Reports

Cobalamin-deficient thrombotic microangiopathy or vitamin B12 deficiency presenting as pseudo-thrombotic microangiopathy is a rare disorder that can be misdiagnosed as thrombotic thrombocytopenic purpura. Patients with this condition are at risk of receiving unnecessary plasmapheresis with a potential delay in appropriate therapy with vitamin B12 supplementation. There are no established diagnostic criteria for this condition in clinical practice. We performed a systematic review of case reports published between January 2018 and January 2023 to analyze the clinical characteristics, risk factors, and patterns of laboratory markers to improve the diagnostic criteria for this condition.

Congenital thrombotic thrombocytopenic purpura masquerading as vitamin B12 deficiency

INTRODUCTION

Congenital thrombotic thrombocytopenic purpura (CTTP), also called Upshaw-Schulman syndrome (USS), is a rare autosomal recessive disorder resulting from the deficiency of the ADAMTS13. CTTP is characterized by the formation of platelet-rich thrombi in small vessels of multiple organs, resulting in thrombocytopenia and microangiopathic hemolytic anemia, eventually leading to organ failure.

CASE REPORT

We present a case of an 11-month-old male infant with CTTP lacking classic features of the disease. Instead, his clinical picture portrayed vitamin B12 deficiency, leading to misdiagnosis and subsequent treatment delay.

CONCLUSION

This case led to the conclusion that congenital TTP should be suspected in case of vitamin B12 deficiency if the child does not respond to the vitamin B12 replacement therapy. We also emphasize that management for CTTP should be started at its earliest in case of increased clinical suspicion to avoid worse outcomes, especially in countries lacking rapid availability of enzyme assay.

Pseudo-Thrombotic Thrombocytopenic Purpura Due to Severe Vitamin B12 Deficiency: A Case Report

Vitamin B12 deficiency is common in vegetarians, as meat is a common source of vitamin B12. In this case presentation, a patient presented to his primary care doctor with signs of severe vitamin B12 deficiency anemia. He had elevated lactate dehydrogenase levels, indirect bilirubin, and schistocytes on the blood smear, all pointing toward a hemolytic process. A severe vitamin B12 deficiency was deemed the cause of this hemolytic anemia after ruling out other causes. We highlight the importance of knowing more about this pathogenesis to avoid unnecessary workup and management for an elementary disorder that can result from severe B12 deficiency.

A Case Report of Cold Agglutinin Disease, Severe B12 Deficiency, and Pernicious Anemia: A Deadly Coincidence

Anemia is the most common hematological disorder. It is commonly a manifestation of an underlying disease. Its causes are multifactorial, including but not limited to nutritional deficiencies, chronic conditions, inflammatory processes, medications, malignancy, renal dysfunction, hereditary diseases, and bone marrow disorders. We present a case of a patient exhibiting anemia related to cold agglutin disease and severe B12 deficiency secondary to pernicious anemia.

Role of the PLASMIC Score in the Management of Thrombotic Thrombocytopenic Purpura

We report the case of a middle-aged male presenting with fatigue and abdominal pain. Prompt investigations demonstrated microangiopathic hemolytic anemia and thrombocytopenia on a peripheral blood smear. Thrombotic thrombocytopenic purpura was suspected based on the PLASMIC score. The patient significantly improved with therapeutic plasma exchange and prednisone within the next few days. The disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 levels reduction is a definitive hallmark leading to microvascular thrombosis. However, some medical centers in the United States do not promptly have quick allowance to the levels. Hence, the PLASMIC score becomes imminent in initiating immediate management and preventing life-threatening complications.

Metabolism-Mediated Thrombotic Microangiopathy in an Older Patient Without Malnutrition

Vitamin B12 deficiency can cause thrombotic microangiopathy (TMA)-like symptoms such as purpura caused by platelet reduction, general fatigue caused by anemia, and renal and hepatic abnormalities caused by malnutrition. TMA-like symptoms are known as metabolism-mediated TMA (MM-TMA). In MM-TMA, blood cell production is altered, and both pancytopenia and schistocytes appear. The initial presentation of MM-TMA makes it challenging to distinguish between primary and secondary TMA when patients do not present risk factors for malnutrition. We encountered an older female patient with a chief complaint of unconsciousness and loss of appetite for two days. Laboratory tests revealed pancytopenia with schistocytes. Moreover, the laboratory data revealed low serum levels of vitamin B12, indicating MM-TMA. The patient was successfully treated with intravenous vitamin B12 supplementation and discharged home. The patient had atrophic gastritis, which could have impeded the absorption of vitamin B12 from food. Among older patients without prolonged appetite loss, TMA-like symptoms should be investigated as MM-TMA induced by vitamin B12 deficiency, and prompt initiation of appropriate treatment is essential to differentiate between MM-TMA and true TMA.

Concomitant Vitamin B1 and Vitamin B12 Deficiency Mimicking Thrombotic Thrombocytopenic Purpura

Vitamin B12 deficiency-induced pseudo-thrombotic thrombocytopenic purpura (pseudo-TTP) is a rare condition. In reported literature, most cases were due to pernicious anemia (confirmed by the presence of anti-parietal cells or anti-intrinsic factor antibodies). Nutritional vitamin B12 deficiency causing pseudo-TTP is a much rarer entity. Differentiating thrombotic thrombocytopenic purpura (TTP) cases from pseudo-TTP (from any cause) should be done as soon as possible since the etiology, treatment, and outcome are different. Hematological findings from pseudo-TTP (when associated with vitamin B12 deficiency) respond to B12 replacement but do not respond to plasmapheresis. Neurological symptoms are one of the criteria for TTP, and altered mentation or psychosis in these cases is presumed secondary to either TTP or vitamin B12 deficiency. However, neurological symptoms are more characteristic of TTP rather than pseudo-TTP. In the rarer subsets of patients concerned with nutritional deficiency and neuropsychiatric symptoms, prompt consideration of concomitant vitamin B1 deficiency and Wernicke encephalopathy is essential. Immediate empiric treatment with high-dose IV thiamine should be started. If unrecognized and left untreated, thiamine deficiency can cause rapid progression to irreversible neurological symptoms, coma, and death, despite hematological improvement with B12 replacement. We report a rare case of concomitant vitamin B12 and vitamin B1 deficiency presenting with confusion, severe hemolytic anemia, acute renal failure, diarrhea, and thrombocytopenia mimicking TTP.

Pernicious Anemia and Vitamin B12 Deficiency Presenting As Pseudothrombotic Microangiopathy and Developing Secondary Thrombocytopenia After Treatment: A Case Report

Pernicious anemia (PA) is an autoimmune disease secondary to chronic atrophic gastritis leading to vitamin B12 deficiency. Rarely, some patients may develop advanced hematological complications that mimic those of thrombotic thrombocytopenic purpura (TTP). Differentiating these conditions is crucial because they require different management. We present a case of a 68-year-old male who presented with generalized weakness, fatigue, and shortness of breath. This patient had anemia, thrombocytopenia, and a markedly deficient serum level of vitamin B12. The symptoms initially mimicked those associated with TTP, but the activity of ADAMTS 13 was normal. A diagnosis of pseudo-TTP has been made due to vitamin B12 deficiency resulting from PA with reactive thrombocytosis. Ultimately, vitamin B12 deficiency pseudo-TTP should be considered a differential diagnosis for therapy refractory TTP because of its different management strategies ranging from parenteral Vitamin B12 in PA patients with highly favorable outcomes to more advanced treatment with less favorable outcomes in TTP patients.

Non-immune Intravascular Hemolytic Anemia, an Unusual Presentation of Severe Vitamin B-12 Deficiency

Vitamin B12 deficiency is a multifactorial condition, with a wide range of clinical presentations from mild to severe anemia and anemia-related neurological deficits. Hemolysis is a unique cause but has increasingly been recognized lately as a possible B12 deficiency presentation. Our patient presented with hemolytic anemia, for which extensive workup has excluded the common hemolysis etiologies. Therefore, it was attributed to B12 deficiency and improved significantly after treatment. Our case highlights the significance of this unusual presentation and its clinical implementation.

Pseudo-thrombotic Microangiopathy Caused by Acquired Cobalamin Deficiency Due to Unintentional Neglect

Acquired vitamin B₁₂ (VB₁₂) deficiency is a rare cause of thrombotic microangiopathy (TMA). We experienced an 86-year-old Japanese woman who presented with coma, renal dysfunction, and microangiopathic hemolytic anemia. Although we initially considered thrombotic thrombocytopenic purpura, we eventually diagnosed her to have VB₁₂ deficiency due to inappropriate dietary care based on her low serum VB₁₂ level, social history, and negative parietal cell finding and the presence of intrinsic factor antibody. Because similar cases are expected to increase in today's aging society, our experience underscores the importance of including acquired VB₁₂ deficiency in the differential diagnosis of TMA, even in elderly patients without a history of gastrectomy.

Chronic Atrophic Gastritis Presenting as Hemolytic Anemia due to Severe Vitamin B12 Deficiency

Vitamin B12 is an essential nutrient which plays an important role in neurological function, hematopoiesis, and DNA synthesis. Low levels usually stem from either poor intake or a malabsorptive process. Presently, the most common cause of vitamin B12 deficiency is food-bound cobalamin malabsorption, which occurs when there is impaired release of vitamin B12 from ingested food due to an outstanding factor preventing the release of the nutrient from its transport protein. Such causes include achlorhydria, gastritis, gastrectomy, or the use of PPIs or antacids. A rarer cause is autoimmune chronic atrophic gastritis, resulting in pernicious anemia. In this disease process, there is destruction of parietal cells and thus a reduction in intrinsic factor, which is essential to the absorption of vitamin B12. Deficiency will result in a variety of abnormalities including but not limited to pancytopenia, paresthesias, and neuropsychiatric symptoms. A rare manifestation of vitamin B12 deficiency is hemolytic anemia, which occurs due to intramedullary and extramedullary dysfunction. This case describes a 46-year-old male with no past medical history who presented with chest pain, fatigue, and progressive weakness, found to have hemolytic anemia, ultimately attributed to vitamin B12 deficiency. Antiparietal cell antibodies and intrinsic factor antibodies (IFA) were both negative. Still, the patient underwent an endoscopy with biopsies of the stomach; pathology was consistent with chronic metaplastic atrophic gastritis. The patient improved with intramuscular vitamin B12 supplementation. This case highlights both a rare cause and presentation of vitamin B12 deficiency. Patients with autoimmune chronic atrophic gastritis should have antiparietal cell or intrinsic factor antibodies. Still, seronegative patients have been reported, like this patient. Additionally, hemolytic anemia secondary to vitamin B12 deficiency is uncommon. The presentation will usually mirror that of a thrombotic microangiopathy (TMA), including hemolytic anemia with schistocytes on peripheral blood smear and thrombocytopenia, as it did in this patient. This clinical entity is described as pseudothrombotic microangiopathy and is crucial to identify in order to prevent the initiation of invasive treatment strategies such as plasmapheresis.

Vitamin B12 Deficiency Presenting With Microangiopathic Hemolytic Anemia

Vitamin B12 has essential roles in DNA synthesis, red blood cell development, and neurologic functions. Vitamin B12 deficiency is relatively common, particularly in people aged over 60 years. Among hematological disturbances, microangiopathic hemolytic anemia with thrombocytopenia or so-called pseudo-thrombotic microangiopathy (pseudo-TMA) is a particularly rare but significant clinical complication in patients with vitamin B12 deficiency. We herein describe a case of an elderly patient with pseudo-TMA whose lack of vitamin B12 was misdiagnosed as thrombotic thrombocytopenic purpura (TTP). The patient was admitted as a case of pancytopenia with a hemolytic picture. The initial impression was TTP versus acute promyelocytic leukemia M3. After examination of laboratory tests and bone marrow examination, we deduced that the patient had a B12 deficiency. The condition of the patient improved with B12 replacement. This report should remind physicians to widen their differential diagnoses when patients present with microangiopathic hemolysis or in patients who are not responsive to standard treatments for TTP.

Suspected Metformin-induced Cobalamin Deficiency Mimicking Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura (TTP) can often be life threatening and requires timely diagnosis and prompt initiation of plasmapharesis. Cobalamin deficiency can closely mimic TTP and distinguishing between the two diseases can prove to be a diagnostic challenge. Previously, cobalamin-related pseudo-TTP has been associated with pernicious anemia, dietary insufficiency and hereditary disorders of cobalamin activation. Here in, we discuss the first case of suspected metformin-induced cobalamin deficiency causing pseudo-TTP. Our patient was a 36-year-old female with type 2 diabetes mellitus on metformin for eight years who presented with hemolytic anemia, thrombocytopenia, schistocytes and mild acute renal failure. The initial impression was TTP; however, further workup revealed very low serum cobalamin levels and elevated methylmalonic acid levels. Apart from metformin use, no other cause of cobalamin deficiency was identified. We recommended upper gastrointestinal endoscopy to definitively rule out pernicious anemia.