Severe Vitamin B12 Deficiency Mimicking Microangiopathic Hemolytic Anemia

Unusual case of pernicious anaemia masquerading as thrombotic thrombocytopenic purpura in the setting of multiple normal vitamin B12 deficiency parameters: preventing anchoring and overdiagnosis

BACKGROUND

Pseudo-thrombotic microangiopathy (pseudo- thrombotic microangiopathy (TMA)) is a rare presentation of B12 deficiency. Overlapping features like elevated LDH/total bilirubin with low haemoglobin/haptoglobin/platelets could deceivingly suggest thrombotic thrombocytopenic purpura (TTP) resulting in avoidable procedures/treatments.

CASE PRESENTATION

A 36-year-old female with hypothyroidism initially presented to clinic with fatigue, palpitations, lightheadedness, and dyspnoea over a 3-month duration and was found to have a haemoglobin of 5.7 g/dL. She received two packed red blood cell units in the emergency room and subsequently discharged with outpatient follow-up and empiric oral iron. During her follow-up visit, she was found to have easy bruisability, gum bleeding, and generalized weakness from hemolytic anaemia (mean corpuscular volume (MCV) 90 fL, haptoglobin <8 mg/dL, LDH >4,000 U/L and schistocytosis on CBC) and thrombocytopenia of 52 K/uL. Due to PLASMIC score of 6 and suspicion for TTP, she was transferred to our facility and tr eated with three cycles of plasma exchange and prednisone but were discontinued when ADAMTS13 levels returned normal. While the patient had normal B12 levels, further testing revealed positive intrinsic factor antibodies (IF-Ab) and an elevated MMA level of 1.56 umol/L. Replacement with cobalamin led to normalization of labs and symptoms.

CONCLUSIONS

Timely diagnosis of pseudo-TMA was exceptionally challenging due to several overlapping features with TTP including normal B12 and normal MCV. B12 levels may falsely appear normal in pernicious anemia due to IF-Ab interference with chemiluminescent immunoassay. Schistocytes lower the MCV in automated cell counters. Lower reticulocyte index (<2%), presence of immature/large platelets and teardrop cells, elevated MMA and a higher LDH (>2500) are indicative of B12 deficiency.

Severe Hemolytic Anemia: Atypical Presentation of Cobalamin Deficiency

Two severe cases of hemolytic anemia are described in different pediatric age groups, both linked to severe cobalamin deficiency from distinct causes. The first case refers to an exclusively breastfed infant with vitamin deficit secondary to maternal impaired absorption. Apart from the neurological deficits present at diagnosis, he also presented with infantile epileptic spasms syndrome a few months after treatment while having normal cobalamin serum levels. The second case refers to an adolescent with long-term inadequate intake. The occurrence of severe hemolytic anemia in cobalamin deficiency is exceptionally rare.

A new perspective on vitamin B12 deficiency in rheumatology: a case-based review

Vitamin B12 (cobalamin) deficiency is common in patients with rheumatic diseases. Pernicious anemia is a well-known cause, but recent reports suggest that autoimmune-derived deficiency may not be limited to this cause alone. Symptoms of low vitamin B12 concentration are often deceptive, mimicking and overlapping with symptoms of other conditions. Neuropsychiatric manifestations, anemia, and fatigue are frequently attributed to a rheumatic disease without further evaluation. In this study, we present three cases of patients with neuropathic pain, depression, fatigue, and muscle weakness, initially attributed to a rheumatic disease, which almost completely resolved after implementing vitamin B12 supplementation. Furthermore, we provide an overview of current scientific reports regarding the potential use of cobalamin in rheumatology. Treatment of pain and neuropathy, often very challenging in long-lasting rheumatic diseases, can be more effective after a course of vitamin B12, even when no apparent deficiency is detected in laboratory tests. Considering recent research demonstrating vitamin B12's nerve-protecting properties, we recommend that physicians should assess vitamin B12 levels early in the diagnostic process of rheumatic diseases. In specific cases, physicians should consider cobalamin supplementation regardless of vitamin B12 serum concentration.

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.

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.

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.

Pseudo-thrombotic microangiopathy due to folate deficiency

Classically, deficiencies of vitamin B12 and folate are associated with megaloblastic anaemia. Additionally, vitamin B12 is able to cause a haemolytic anaemia in the form of pseudo-thrombotic microangiopathy (pseudo-TMA). Here, we present a case of a middle-aged woman with a history of Roux-en-Y gastric bypass who presented with dyspnoea and fatigue and was found to have thrombocytopenia and a non-immune haemolytic anaemia. Work-up for haemolytic uraemic syndrome, thrombotic thrombocytopenic purpura, paroxysmal nocturnal haemoglobinuria, infection, malignancy and autoimmune conditions was unremarkable. Her haemolytic anaemia and thrombocytopenia resolved with folate replenishment. She was diagnosed as likely having pseudo-TMA secondary to folate deficiency.

Pseudo-Thrombotic Microangiopathy Secondary to Vitamin B12 Deficiency

Background

Clinical B₁₂ deficiency with hematological or neurological manifestations is rare. An unusual manifestation of B₁₂ deficiency is pseudo-thrombotic microangiopathy (TMA), which is characterized by hemolytic anemia, thrombocytopenia, and schistocytosis and only occurs in 2.5% of those with B₁₂ deficiency. Pseudo-TMA is misdiagnosed as thrombotic thrombocytopenic purpura (TTP) in 40% of cases, resulting in misguided treatment including plasmapheresis.

Case

A 44-year-old Hispanic presented with 3 weeks of progressively worsening non-radiating chest pain, fatigue, and shortness of breath (SOB). Laboratory findings revealed severe pancytopenia and macrocytosis with a hemoglobin of 5.4 g/dL, mean corpuscular volume of 116.3 fL, and vitamin B₁₂ low at 149 pg/mL. She was diagnosed with pseudo-TMA and after starting 1000 micrograms of parenteral vitamin B₁₂ injections daily and discontinuing plasmapheresis and steroid administration, she improved.

Conclusion

Failure to recognize pseudo-TMA often results in unnecessary treatment with plasmapheresis and delays appropriate treatment with vitamin B₁₂ supplementation. It is therefore extremely important to consider pseudo-TMA as a differential diagnosis in patients that present with hemolytic anemia, thrombocytopenia, and schistocytosis.

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.