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

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.

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.

Vitamin B12 levels in patients with retinal vein occlusion and their relation with clinical outcome: a retrospective study

Retinal vein occlusion (RVO) is the second most common retinal vascular disorder, after diabetic retinopathy. Most patients suffering RVO develop some degree of visual loss consequent to retinal complications such as edema and microhemorrhages. Even if some risk factors for RVO have been identified, the clinical outcome of RVO remains highly unpredictable because studies investigating potential prognostic markers for visual improvement are lacking. Cyanocobalamin belongs to the group of B vitamins and plays a role in homocysteine metabolism; however, cyanocobalamin deficiency associates with an increase of some toxic bioproducts involved in endothelial injury and platelet activation independent of homocysteine levels. We retrospectively evaluated the levels of vitamin B12 at diagnosis in 203 patients with RVO, and in a parallel cohort of 120 age- and sex-matched patients without RVO from an internal medicine ward, and correlated them with visual outcome at follow-up (median time 150 days, IQR 30-210). In patients with RVO, vitamin B12 levels at diagnosis were significantly lower than in controls and independently predicted worse clinical outcome at multivariate analysis (OR 3.2; CIs 1.2-8.2; p = 0.015). Our data suggest the opportunity to prospectively evaluate the effect on visual outcome of cyanocobalamin supplementation in RVO patients.

Metabolism-mediated thrombotic microangiopathy and B12

Thrombotic microangiopathies (TMAs) are a group of life-threatening conditions requiring urgent management and characterized by a clinical triad of microangiopathic hemolytic anemia, thrombocytopenia, and ischemic tissue injury. Severe vitamin B12 (Cobalamin-Cbl) deficiency or defective cobalamin metabolism, particularly defects in intracellular B12 metabolism, may lead to a TMA-like picture. The latter has been termed metabolism-mediated TMA (MM-TMA). This confusing picture is mediated partly by ineffective erythropoiesis with significant red cell fragmentation resulting in a hemolytic pattern, coupled with reduced platelet production and endothelial injury with organ damage resulting from accumulated toxic byproducts of B12 dysmetabolism. However, unlike in classic thrombotic thrombocytopenic purpura, where therapeutic plasma exchange has to be initiated promptly, cases of MM-TMA can be treated, if diagnosed properly, with adequate B12 replacement.

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.