Iron deficiency in pernicious anemia: Specific features of iron deficient patients and preliminary data on response to iron supplementation.

BACKGROUND & AIMS: While vitamin B12 (B12) deficiency is considered as the hallmark of pernicious anemia (PA), iron deficiency (ID) is also prevalent. Indeed, this auto immune gastritis is responsible for parietal cell atrophy and increase in gastric pH, leading to impaired iron absorption. We compared PA patients' features according to their iron status at PA diagnosis, and we assessed the iron status recovery after oral or intravenous iron supplementation. METHODS: We prospectively included patients presenting with a newly diagnosed PA in a tertiary referral hospital between November 2018 and October 2020. Iron status was assessed at PA diagnosis then regularly during a standardized follow-up. In case of ID, the decision of treatment with oral and/or intravenous iron supplementation was left to the clinician convenience. RESULTS: We included 28 patients with newly diagnosed PA. ID was observed in 21/28 (75.0%) patients: from the PA diagnosis in 13 patients, or during the follow-up in 8 patients. Iron deficient PA patients had higher plasma B12 (p = 0.04) and lower homocysteine levels (p = 0.04). Also, ID was independently associated with the 'APCA (anti-parietal cell antibodies) alone' immunological status (absence of anti-intrinsic factor antibodies) after adjustment for age, gender and B12 level (aOR 12.1 [1.1-141.8], p = 0.04). High level of APCA was associated with lower ferritin level. After 3 months of supplementation, 3/11 PA patients normalized the iron status with oral iron supplementation, versus 7/8 with intravenous iron supplementation (p = 0.02). CONCLUSION: The high frequency of iron deficiency in PA highlights the interest of regular assessment of iron status in this condition. ID was associated with a profile including APCA alone and less pronounced B12 deficiency. Intravenous iron supplementation seemed to be more efficient than an oral supplementation in these preliminary data.

The MMACHC variant c.158T>C: Mild clinical and biochemical phenotypes and marked hydroxocobalamin response in cblC patients.

Mutations in MMACHC cause cobalamin C disease (cblC, OMIM 277400), the commonest inborn error of vitamin B12 metabolism. In cblC, deficient activation of cobalamin results in methylcobalamin and adenosylcobalamin deficiency, elevating methylmalonic acid (MMA) and total plasma homocysteine (tHcy). We retrospectively reviewed the medical files of seven cblC patients: three compound heterozygotes for the MMACHC (NM_015506.3) missense variant c.158T>C p.(Leu53Pro) in trans with the common pathogenic mutation c.271dupA (p.(Arg91Lysfs*14), "compounds"), and four c.271dupA homozygotes ("homozygotes"). Compounds receiving hydroxocobalamin intramuscular injection monotherapy had age-appropriate psychomotor performance and normal ophthalmological examinations. In contrast, c.271dupA homozygotes showed marked psychomotor retardation, retinopathy and feeding problems despite penta-therapy (hydroxocobalamin, betaine, folinic acid, l-carnitine and acetylsalicylic acid). Pretreatment levels of plasma and urine MMA and tHcy were higher in c.271dupA homozygotes than in compounds. Under treatment, levels of the compounds approached or entered the reference range but not those of c.271dupA homozygotes (tHcy: compounds 9.8-32.9 µM, homozygotes 41.6-106.8 (normal (N) < 14); plasma MMA: compounds 0.14-0.81 µM, homozygotes, 10.4-61 (N < 0.4); urine MMA: compounds 1.75-48 mmol/mol creatinine, homozygotes 143-493 (N < 10)). Patient skin fibroblasts all had low cobalamin uptake, but this was milder in compound cells. Also, the distribution pattern of cobalamin species was qualitatively different between cells from compounds and from homozygotes. Compared to the classic cblC phenotype presented by c.271dupA homozygous patients, c.[158T>C];[271dupA] compounds had mild clinical and biochemical phenotypes and responded strikingly to hydroxocobalamin monotherapy.

Subacute Combined Degeneration of the Spinal Cord Induced by Nitrous Oxide Abuse: A Rare Patient Presentation to a Spine Surgery Clinic: Illustrative Case.

Subacute combined degeneration (SCD) of the spinal cord is a disease involving the lateral and posterior columns of the spinal cord that can manifest in patients with vitamin B12 deficiency. Nitrous oxide (N2O)-induced SCD of the spinal cord is a result of N2O interfering with the metabolism of vitamin B12 and results in nervous system demyelination. This is an infrequent complication of N2O anesthesia; however, cases are rising with recreational N2O use. This case report describes a patient with SCD of the spinal cord induced by recreational N2O abuse. The patient presented to a spine surgery clinic with a 3-week history of progressive global weakness and paresthesias. After a detailed history and physical examination, the diagnosis was made and supported by various tests and imaging findings. Despite marked neurologic deficits, the patient's symptoms improved markedly with therapy and vitamin B12 supplementation. Spine surgery clinicians may be confronted with these cases and should be aware of this atypical presentation of SCD. As in our case, patients may present with neurologic deficits of unclear etiology. Neurologic dysfunction may be irreversible; therefore, accurate diagnosis, medical treatment, and complete neurologic evaluation are of the utmost importance to prevent additional progression.

Would, early, versus late hydroxocobalamin dose intensification treatment, prevent cognitive decline, macular degeneration and ocular disease, in 5 patients with early-onset cblC deficiency?

In early-onset (EO) cblC deficiency (MMACHC), hydroxocobalamin dose-intensification (OHCBL-DI) improved biochemical and clinical outcome. In mammals, Cobalamin is reduced, in a reaction mediated by MMACHC. Pathogenic variants in MMACHC disrupt the synthesis pathway of methyl-cobalamin (MetCbl) and 5'-deoxy-adenosyl-cobalamin (AdoCbl), cofactors for both methionine synthase (MS) and methyl-malonyl-CoA mutase (MCM) enzymes. In 5 patients (pts.), with EO cblC deficiency, biochemical and clinical responses were studied following OHCbl-DI (mean ± SD 6,5 ± 3,3 mg/kg/day), given early, before age 5 months (pts. 1, 2, 3 and 4) or lately, at age 5 years (pt. 5). In all pts., total homocysteine (tHcy), methyl-malonic acid (MMA) and Cob(III)alamin levels were measured. Follow-up was performed during 74/12 years (pts. 1, 2, 3), 33/12 years (pt. 4) and 34/12 years (pt. 5). OHCbl was delivered intravenously or subcutaneously. Mean ± SD serum Cob(III)alamin levels were 42,2 × 106 ± 28, 0 × 106 pg/ml (normal: 200-900 pg/ml). In all pts., biomarkers were well controlled. All pts., except pt. 5, who had poor vision, had central vision, mild to moderate nystagmus, and with peri-foveolar irregularity in pts. 1, 2 and 4, yet none had the classic bulls' eye maculopathy and retinal degeneration characteristic of pts. with EO cblC deficiency. Only pt. 5, had severe cognitive deficiency. Both visual and cognitive functions were better preserved with early than with late OHCBL-DI. OHCBL-DI is suggested to bypass MMACHC, subsequently to be rescued by methionine synthase reductase (MSR) and adenosyl-transferase (ATR) to obtain Cob(I)alamin resulting in improved cognitive and retinal function in pts. with EO cblC deficiency.

Autoimmune gastritis as an unexpected cause of diarrhea in a young adult with type I diabetes: a case report.

BACKGROUND: Type 1 diabetes mellitus (T1DM) is a lifelong diagnosis that involves immune-mediated damage of pancreatic beta cells and subsequent hyperglycemia, manifesting as: polyuria, polydipsia, polyphagia, and weight loss. Treatment of type 1 diabetes centers on insulin administration to replace or supplement the body's own insulin with the goal of achieving euglycemia and preventing or minimizing complications. Patients with T1DM are at risk for developing other autoimmune conditions, most commonly thyroid or celiac disease. CASE PRESENTATION: A 20-year-old African American female with T1DM was referred by her endocrinologist to pediatric gastroenterology for 2 months of nocturnal, non-bloody diarrhea, left lower quadrant pain, and nausea; she was also being followed by neurology for complaints of lower extremity paresthesias and pain. The patient's initial lab-workup was remarkable for a low total Immunoglobulin A (IgA) level of < 6.7 mg/dL. As IgA deficiency is associated with an increased risk of celiac disease, the patient underwent upper and lower endoscopy, which was grossly unremarkable; however, histology revealed a pattern consistent with autoimmune gastritis. Subsequent serum evaluation was remarkable for an elevated fasting gastrin level and an elevated parietal cell antibody level without macrocytic anemia, iron deficiency, or vitamin B12 depletion. The patient was diagnosed with autoimmune gastritis (AIG) and subsequently initiated on parenteral B12 supplementation therapy with improvement in her neurologic and gastrointestinal symptoms. CONCLUSION: This case illustrates the importance of recognition of red flag findings in a patient with known autoimmune disease. Following well-established health maintenance recommendations for individuals with T1DM ensures that common comorbidities will be detected. Autoimmune gastritis, while a rarer pathology in the pediatric population, deserves consideration in patients with pre-existing autoimmune conditions and new gastrointestinal or neurologic symptoms, as AIG can be associated with poor outcomes and risk of malignancy. Initial lab findings associated with an eventual diagnosis of AIG typically include anemia, iron deficiency, or Vitamin B12 deficiency. However, as demonstrated in this case, symptoms of AIG can rarely present before anemia or Vitamin B12 deficiency develops. To prevent permanent neurological damage, parenteral Vitamin B12 therapy must be considered even in the absence of Vitamin B12 deficiency, especially in those patients already experiencing neurological symptoms.

Effect of Roselle Flower Extract (Hibiscus sabdariffa Linn.) on Reducing Steatosis and Steatohepatitis in Vitamin B12 Deficiency Rat Model.

Background and Objectives: Non-alcoholic Fatty Liver Disease (NAFLD) can occur as a result of micronutrient deficiencies. Hibiscus sabdarifa, a plant used in traditional medicine, contains ingredients that can help prevent this process. This study looked at the potency of Hibiscus sabdariffa Ethanol Extract (HSE) to prevent homocysteine-induced liver damage in animals that were deficient in vitamin B12. Materials and Methods: A comparative study of the effects of roselle extract is presented in an experimental design. Thirty Sprague-Dawley rats were divided into six groups using randomization. To demonstrate the absence of liver damage in the experimental animals under normal conditions, a control group was fed a normal diet without HSE. For the induction of liver damage in the experimental animals, the vitamin B12-restricted group was administered a vitamin B12-restricted diet. To test the effect of HSE on liver damage, the treatment group was given HSE along with a vitamin B12-restricted diet. Each group was given two treatment periods of eight and sixteen weeks. These results were compared with the results of the parameter examination between the vitamin B12 restriction group, with and without HSE, using an ANOVA statistic. The data were analyzed with licensed SPSS 20.0 software. Results: HSE significantly increased the blood levels of vitamin B12 while lowering homocysteine levels. The administration of HSE reduced liver damage based on the activity of liver function enzymes in the plasma due to a limitation of vitamin B12. HSE decreased Sterol Regulatory Element-Binding Protein-1c (SREBP1c) and Nuclear Factor Kappa B (NFkB) protein expressions in the liver tissue, but did not decrease Glucose-Regulated Protein 78 (GRP78) protein expression. Significantly, the levels of Tumor Necrosis Factor alpha (TNF-a) and IL-6 in the liver tissue were lower, while the levels of IL-10 and Nuclear factor-erythroid-2 Related Factor 2 (NRF2) were higher with HSE administration. HSE produced a better histopathological profile of the Hematoxylin and Eosin (H&E)-Masson tricrome for inflammation, fat and fibrosis in the liver. Conclusions: In this study, HSE was found to slow the development of liver damage in experimental animals that were given a vitamin B12-deficient diet.

Vitamin B12: For more than just the treatment of megaloblastic anemia?

Vitamin B12, or cobalamin, belongs to the group of water-soluble vitamins and is ingested through food of animal origin such as eggs, milk, red meat and poultry, fish, and shellfish. Its clinical indication is the treatment of hypovitaminosis B12 administered orally or intramuscularly in the form of hydroxocobalamin. Hypovitaminosis B12 is mainly caused by deficient dietary intake (individuals with malnutrition, vegetarians or vegans, older adults, pregnant people, individuals with alcohol use disorder); when intestinal absorption is reduced (atrophic gastritis, malabsorption syndrome, gastrointestinal surgery); and for causes associated with the intake of drugs (antacids, metformin). Hypervitaminosis B12 has been associated with renal failure; liver diseases such as cirrhosis and acute-phase hepatitis; alcohol use disorder with or without liver involvement; solid tumors of the lung, liver, esophagus, pancreas, and colorectum; and in hematological malignancies such as leukemia and bone marrow dysplasia.

A Safe and Novel Outpatient Subcutaneous Vitamin B12 Desensitization Protocol in A Patient with Crohn's Disease and Vitamin B12 Allergy: A Case Report.

INTRODUCTION: Although rare, some patients may have a vitamin B12 allergy. Crohn's disease commonly leads to significant vitamin B12 deficiency, especially in those patients that have undergone ileal resection. In these difficult cases, vitamin B12 desensitization may be required. CASE PRESENTATION: Here, we report a successful case of a serial outpatient subcutaneous vitamin B12 desensitization protocol in a 35-year-old female with a past medical history of Crohn's disease status post ileal resection, subsequent vitamin B12 deficiency, and allergy to subcutaneous vitamin B12. CONCLUSION: This is the first subcutaneous vitamin B12 desensitization protocol reported to have been safely performed in the outpatient setting.

Vitamin B12 supplementation post-gastrectomy: a service closed-loop audit at St. James's Hospital, Dublin.

BACKGROUND: Vitamin B12 (VB12) deficiency is a well-described complication post-gastrectomy. It is caused by the loss of parietal cell mass leading to megaloblastic anaemia. This closed-loop audit assesses patient understanding of and adherence with VB12 supplementation guidelines post-gastrectomy. METHODS: A closed-loop audit cycle was performed. After the first cycle, an educational intervention was actioned prior to re-audit. One hundred twenty-five patients who underwent gastrectomy between 2010 and 2020 were available for study (86 total gastrectomies (TG), 39 subtotal gastrectomies (STG)). Twenty-nine patients who had not been adherent with VB12 supplementation/surveillance were eligible for re-audit. RESULTS: 91.9% (79/86) of TG patients reported adherence in regular parenteral VB12 supplementation. Adherence was significantly lower for STG for checking (and/or replacing) their VB12, with only 53.8% (21/39) checking their VB12 levels. 67/125 (53.6%) of the patients stated that they knew it was important to supplement B12 post-gastrectomy. 37.8% (43/113) of participants could explain why this was important, and 14.4% (18/125) had any knowledge of the complications of VB12 deficiency. Following re-audit, 5/8 (57.5%) of TG patients who had not been adherent with VB12 supplementation in the first cycle were now adherent with VB12 supplementation following our educational intervention. 7/17 (41.2%) of the STG group had received VB12 or made arrangements to receive supplemental VB12 if it was indicated. CONCLUSION: This study demonstrates good adherence in those undergoing TG. Patient understanding correlates with adherence, suggesting that patient education and knowledge reinforcement may be key to adherence with VB12 supplementation. A simple educational intervention can improve adherence with VB12 supplementation in patients undergoing gastrectomy.

A case report: subacute combined degeneration of the spinal cord and pernicious anemia caused by autoimmune gastritis.

INTRODUCTION: Autoimmune gastritis causing both subacute combined degeneration of the spinal cord and pernicious anemia is rare in clinical practice. Here, we report a case of subacute combined degeneration of the spinal cord and pernicious anemia resulting from vitamin B12 deficiency due to autoimmune gastritis. PATIENT CONCERNS: A 66-year-old woman presented with a 2-month history of numbness in her extremities. DIAGNOSES: The diagnoses were (1) autoimmune gastritis (2) subacute combined degeneration of the spinal cord (3) pernicious anemia (4) hypergastrinemia (5) chronic lymphocytic thyroiditis. INTERVENTIONS: The patient received intramuscular methylcobalamin treatment for 5 days, followed by oral methylcobalamin daily.Outcomes: Symptoms improved, and anemia recovered in the second month after discharge. She discontinued her medication afterward, and the neurological symptoms recurred. CONCLUSIONS: Autoimmune gastritis can lead to several diseases if not intervened in the early course. Neuropathy and hematopathy recur with treatment discontinuity. Methylcobalamin and adenosylcobalamin are unlikely to be more effective than vitamin B12.

Phase II Study of a Multi-center Randomized Controlled Trial to Evaluate Oral Vitamin B12 Treatment for Vitamin B12 Deficiency After Total Gastrectomy in Gastric Cancer Patients.

BACKGROUND/AIM: This prospective multi-central randomized phase II trial evaluated the efficacy and safety of oral Vitamin B12 500 µg/day replacement compared with oral Vitamin B12 1,500 µg/day in patients with Vitamin B12 deficiency after total gastrectomy for gastric cancer. PATIENTS AND METHODS: Patients were randomly assigned to receive oral Vitamin B12 500 µg/day or Vitamin B12 1,500 µg/day in a 1:1 ratio with a minimization method. The primary endpoint was the incidence of a normal serum Vitamin B12 level at three months after treatment. RESULTS: From January 2018 to December 2021, 3 institutions collaborated with the present study, and 74 patients were registered from these 3 institutions. The study was prematurely closed due to poor accrual after reaching almost 50% of its goal. Among the 74 recruited patients, 36 were allocated to the Vitamin B12 500 µg/day arm and 38 to Vitamin B12 1,500 µg/day arm. The incidences of patients with a normal Vitamin B12 level at 3 months (serum Vitamin B12 level >200 pg/ml) were 91.7% (33/36) in the Vitamin B12 500 µg/day arm and 100% (38/38) in the Vitamin B12 1,500 µg/day arm (p=0.3587). The types of clinical symptoms with Vitamin B12 deficiency that improved with Vitamin B12 treatment and the degree of improvement were also similar. CONCLUSION: Although the primary endpoint of the present study was not met, it was found that oral Vitamin B12 500 µg/day replacement is as effective and safe as oral Vitamin B12 1,500 µg/day replacement for Vitamin B12 deficiency.

Effects of vitamin B12 supplementation on pain relief in certain diseases - a literature review.

Based on current scientific reports, vitamin B12 (cobalamin), used in the treatment of pernicious anemia, may be used as a pain reliever. It has been shown to be effective in the treatment of different sorts of pain, including diabetic neuropathic, musculoskeletal, abdominal, back and spine ones, but also pain in Alzheimer's disease and pain ailments resulting from the development of neoplasms. In addition, it helps regeneration of the sensory nerves and relieves pain in eye diseases, for example in dry eye syndrome. This review summarizes recent research reports on pain-relieving properties of vitamin B12.

Combined action of SAMe, Folate, and Vitamin B12 in the treatment of mood disorders: a review.

Mood disorders affect more than 500 million people around the world. In the last decade, their prevalence has increased, and many people suffer from nervousness, anxiety, and stress at least once in their lives. The incidence of mood disorders and anxiety increases during perimenopause or under stressful conditions. The social restrictions introduced during the COVID-19 pandemic have significantly increased the normal burden of psychological and psychic disorders. In moderate to severe cases, pharmacological treatment is currently recommended, while in mild disorders, especially in the initial phase, psychological therapy is preferable. It is known that several nutrients are crucial for brain function. Among them, folate (vitamin B9), cyanocobalamin (vitamin B12), and S-adenosyl-L-methionine (SAMe) have been shown to influence various neurobiological processes. Overall, the available evidence suggests that dietary supplementation with folic acid, vitamin B12, and SAMe can be beneficial for people with mild mood disorders.

[The use of vitamin B12 in cancer patients]. / Primenenie vitamina B12 u onkologicheskikh bol'nykh.

Based on the data of foreign and domestic literature, the question of the possible carcinogenesis of vitamin B12 and the expediency of its administration to patients with cancer who have neurological complications due to chemotherapy is analyzed. The absence of convincing direct evidence of the carcinogenic effect of cyanocobalamin has been demonstrated, as well as the reasonableness of drug correction of vitamin B12 deficiency in cancer patients in order to prevent the development of characteristic deficient neurological disorders. The question of the effectiveness of oral administration of cyanocobalamin at a dose of 1 mg per day is considered.

Adult-onset CblC deficiency: a challenging diagnosis involving different adult clinical specialists.

BACKGROUND: Methylmalonic aciduria and homocystinuria, CblC type (OMIM #277400) is the most common disorder of cobalamin intracellular metabolism, an autosomal recessive disease, whose biochemical hallmarks are hyperhomocysteinemia, methylmalonic aciduria and low plasma methionine. Despite being a well-recognized disease for pediatricians, there is scarce awareness of its adult presentation. A thorough analysis and discussion of cobalamin C defect presentation in adult patients has never been extensively performed. This article reviews the published data and adds a new case of the latest onset of symptoms ever described for the disease. RESULTS: We present the emblematic case of a 45-year-old male, describing the diagnostic odyssey he ventured through to get to the appropriate treatment and molecular diagnosis. Furthermore, available clinical, biochemical and molecular data from 22 reports on cases and case series were collected, resulting in 45 adult-onset CblC cases, including our own. We describe the onset of the disease in adulthood, encompassing neurological, psychiatric, renal, ophthalmic and thromboembolic symptoms. In all cases treatment with intramuscular hydroxycobalamin was effective in reversing symptoms. From a molecular point of view adult patients are usually compound heterozygous carriers of a truncating and a non-truncating variant in the MMACHC gene. CONCLUSION: Adult onset CblC disease is a rare disorder whose diagnosis can be delayed due to poor awareness regarding its presenting insidious symptoms and biochemical hallmarks. To avoid misdiagnosis, we suggest that adult onset CblC deficiency is acknowledged as a separate entity from pediatric late onset cases, and that the disease is considered in the differential diagnosis in adult patients with atypical hemolytic uremic syndromes and/or slow unexplained decline in renal function and/or idiopathic neuropathies, spinal cord degenerations, ataxias and/or recurrent thrombosis and/or visual field defects, maculopathy and optic disc atrophy. Plasma homocysteine measurement should be the first line for differential diagnosis when the disease is suspected. To further aid diagnosis, it is important that genes belonging to the intracellular cobalamin pathway are included within gene panels routinely tested for atypical hemolytic uremic syndrome and chronic kidney disorders.

Evaluation of the response to vitamin B12 supplementation in patients with atrophy in sleeve gastrectomy materials.

OBJECTIVE: Vitamin B12 deficiency can be seen in the cases with sleeve gastrectomy. Because the chief factor in vitamin B12 deficiency is gastric atrophy, we aimed to evaluate the effect of atrophy on postoperative vitamin B12 levels in patients who underwent sleeve gastrectomy. MATERIAL AND METHODS: Sixty patients were included in this study. Vitamin B12 levels were compared with presence of atrophy before the operation and after vitamin B12 supplementation. RESULTS: Atrophy was observed in 37 (61.7%) of the cases; 23 (38.3%) patients had no atrophy. There was a statistically significant difference between the presence of atrophy and vitamin B12 levels (p = 0.024). Despite vitamin B12 support, there were statistically significant low vitamin B12 levels after the operation in female patients having atrophy (p = 0.023). The same significance was not observed in males (p = 0.480). CONCLUSION: Vitamin B12 deficiency following obesity surgery is a condition that must be monitored and prevented. We found that histopathologically confirmed atrophy had an adverse effect on postoperative vitamin B12 levels. These findings can be a guide for the clinicians in the management of these cases.

OBJETIVO: La deficiencia de vitamina B12 se puede observar en los casos de gastrectomía en manga. Debido a que el factor principal en la deficiencia de vitamina B12 es la atrofia gástrica, nuestro objetivo fue evaluar el efecto de la atrofia en los niveles posoperatorios de vitamina B12 en pacientes que se sometieron a gastrectomía en manga. MATERIAL Y MÉTODOS: se incluyeron 60 pacientes en este estudio. Los niveles de vitamina B12 se compararon con la presencia de atrofia antes de la operación y después de la suplementación con vitamina B12. RESULTADOS: Se observó atrofia en 37(61.7%) de los casos; 23 (38.3%) pacientes no presentaron atrofia. Hubo una diferencia estadísticamente significativa entre la presencia de atrofia y los niveles de vitamina B12 (p = 0.024). A pesar del apoyo de vitamina B12, hubo niveles bajos de vitamina B12 estadísticamente significativos después de la operación en pacientes femeninas con atrofia (p = 0.023). No se observó la misma significación en los hombres (p = 0.480). CONCLUSIONES: La deficiencia de vitamina B12 luego de una cirugía de obesidad es una condición que debe ser monitoreada y prevenida. Encontramos que la atrofia confirmada histopatológicamente tuvo un efecto adverso sobre los niveles posoperatorios de vitamina B12. Estos hallazgos pueden ser una guía para los médicos en el manejo de estos casos.

Macro-B12 masking B12 deficiency.

In clinical practice, the finding of an elevated serum B12 concentration is often the consequence of supplementation with B12 in either oral form or injections. Also, elevated serum B12 may be associated with underlying disorders, like liver diseases or a (haematologic) malignancy. Only a few studies have shown that it may also be the consequence of complex formation of B12-vitamin binding proteins with immunoglobulins, the so-called macro-B12 We describe a young woman who previously was diagnosed with B12 deficiency, and in whom, after cessation of B12 injection treatment, neurologic symptoms re-appeared, and despite this, repeatedly elevated serum B12 concentrations above the upper limit of the assay were found. We demonstrated that this was caused by the presence of macro-B12, which not only resulted in erroneous and longstanding elevated serum B12, but also masked her underlying B12 deficiency.

How I investigate acquired megaloblastic anemia.

In this review of megaloblastic anemia (MA), an overview of vitamin B12 and folate body requirements, biochemical pathways, and laboratory testing strategies will be provided. However, the focus of this review is the classic and unique features of MA in blood and bone marrow. Acquired MA is a benign disorder for many, but can be detrimental for some. The clinical presentation can vary considerably, and the spectrum of symptoms and signs is diverse and quite broad. Prompt recognition and therapy are critical to prevent potential irreversible damage and clinical sequelae, especially in patients with vitamin B12 deficiency. A delay in diagnosis of vitamin B12 deficiency can result in significant neurologic sequelae that may not fully resolve with treatment, including in neonates and young infants. The blood and bone marrow features in MA can closely mimic thrombocytopenic purpura, myelodysplasia, and other myeloid neoplasms. Both pancytopenia and normal MCV at presentation are common in MA and raise unique challenges for the diagnostician. Partially treated MA is also a significant diagnostic "trap". MA is highly responsive to treatment, and patients tend to improve rapidly upon treatment initiation. However, the broad range of clinical and hematologic features makes the rapid, successful diagnosis of MA a unique challenge for the hematopathologist. Even in the era of state-of-the-art laboratory testing, a high suspicion is required.

Autoimmune gastritis concomitant with gastric adenoma and subacute combined degeneration of the spinal cord.

A 62-year-old woman was referred to our department for further investigation of anaemia. Blood test showed macrocytic anaemia. Oesophagogastroduodenoscopy (OGD) revealed proximal-predominant gastric atrophy and flat elevated lesion in the gastric body. Several days after OGD, she complained of gait disturbance and was diagnosed with subacute combined degeneration of the spinal cord. Furthermore, laboratory tests showed positive for both anti-parietal cell and anti-intrinsic factor antibodies, as well as increased serum gastrin level and decreased pepsinogen I level, which confirmed the diagnosis of autoimmune gastritis (AIG). Anaemia and neurological symptoms were improved after vitamin B12 supplementation. Subsequently, the patient underwent gastric endoscopic submucosal dissection; histopathological examination revealed gastric adenoma. AIG can cause gastric neoplasms and vitamin B12 deficiency, with the latter resulting in pernicious anaemia and neurological disorders. These diseases are treatable but potentially life-threatening. This case highlights the importance of early diagnosis of AIG and proper management of its comorbidities.

Pernicious anemia: Pathophysiology and diagnostic difficulties.

Pernicious anemia (PA) is the most common cause of vitamin B12 (cobalamin) deficiency anemia in the world. It is an autoimmune disease, comprising of salient features of autoimmune chronic atrophic gastritis (CAG) and cobalamin deficiency (CD). Although the anemia was first described as pernicious, it may well be controlled with vitamin B12 replacement. The onset and progression of PA is often insidious. Alternatively, patients may have no anemic symptoms since they become acclimatized to the subtle nature of the disease. Oftentimes, there is a possibility that the underlying disease may be missed unless a full blood count (FBC) is investigated, leading to hindrance in the treatment journey. Diagnostic challenges remain tangible for many practicing clinicians, since there is lack of reliable cobalamin assays to diagnose CD as well as clinical mimics, which simulate many other hematological conditions, such as myelodysplastic syndrome, acute leukemia, sideroblastic anemias, bone marrow failure states, thrombotic microangiopathy, and thromboembolism. Moreover, prompt recognition of the symptoms of CD is also vital, because some neurologic sequalae may become irreversible despite replenishing cobalamin. Herein, we discuss a literature review on the pathophysiology, challenging clinical presentations and diagnostic difficulties of PA. Since the cobalamin replacement therapy for PA is straightforward, it will not be discussed in this review.