Challenging illness scripts: a case of pernicious anaemia and axonal neuropathy.

This case report presents a male in his 30s with pernicious anaemia, initially diagnosed with autoimmune haemolytic anaemia and thrombocytopenia. Despite improvement with treatment, he developed bilateral leg weakness and numbness, ultimately diagnosed as peripheral neuropathy. Further investigations revealed a spectrum of haematological and neurological manifestations associated with B12 deficiency, challenging the typical illness script of pernicious anaemia. This report underscores the importance of recognising variations in clinical presentation and highlights the need for expanded illness scripts to guide accurate diagnosis and management.

Folate and Vitamin B12 Status in Women of Reproductive Age in Rural Haryana, India: Estimating Population-Based Prevalence for Neural Tube Defects.

BACKGROUND: Folate and vitamin B12 deficiencies in pregnant women are associated with increased risk for adverse maternal and infant health outcomes, including neural tube defects (NTDs). METHODS: A population-based cross-sectional survey was conducted in two rural areas in Ambala District, Haryana, India in 2017 to assess baseline folate and vitamin B12 status among women of reproductive age (WRA) and predict the prevalence of NTDs. We calculated the prevalence of folate and vitamin B12 deficiency and insufficiency by demographic characteristics among 775 non-pregnant, non-lactating WRA (18-49 years). Using red blood cell (RBC) folate distributions and an established Bayesian model, we predicted NTD prevalence. All analyses were conducted using SAS-callable SUDAAN Version 11.0.4 to account for complex survey design. RESULTS: Among WRA, 10.1% (95% CI: 7.9, 12.7) and 9.3% (95% CI: 7.4, 11.6) had serum (<7 nmol/L) and RBC folate (<305 nmol/L) deficiency, respectively. The prevalence of RBC folate insufficiency (<748 nmol/L) was 78.3% (95% CI: 75.0, 81.3) and the predicted NTD prevalence was 21.0 (95% uncertainly interval: 16.9, 25.9) per 10,000 live births. Prevalences of vitamin B12 deficiency (<200 pg/mL) and marginal deficiency (≥200 pg/mL and ≤300 pg/mL) were 57.7% (95% CI: 53.9, 61.4) and 23.5% (95% CI: 20.4, 26.9), respectively. CONCLUSIONS: The magnitude of folate insufficiency and vitamin B12 deficiency in this Northern Indian population is a substantial public health concern. The findings from the survey help establish the baseline against which results from future post-fortification surveys can be compared.

Diagnostic Signs and Symptoms of Cyanocobalamin Deficiency at Rural Setting in India: Novel Method of Supplementation.

BACKGROUND: Cyanocobalamin or B12 deficiency is common in the Indian population, and responsible for anemia. Various clinical manifestations include central nervous system and cardiovascular manifestations, secondary to a rise in serum homocysteine levels. METHOD AND PATIENTS: In a routine outpatient department at Bawaskar Hospital and Clinical Research Centre, Mahad, patients with suspected clinical signs and symptoms suggestive of cyanocobalamin deficiency were studied in detail regarding their dietary habits, serum hemoglobin, B12, and homocysteine levels. FINDINGS: A total of 1,992 (female 1,009, 50.75%) were clinically examined in detail. Of these, 945 (49.94%), 999 (50.17%), and 48 (2.40%) were strict vegetarians, both vegetarian and nonvegetarian, and strict nonvegetarians, respectively. Common occupations associated with B12 deficiency include 666 (33.4%) housewives, 396 (19.9%) service workers, 316 (15.9%) businesspeople, 180 (9%), and 198 (9.9%) retired and industrial populations, respectively. Clinical manifestations include recurrent scalp hair loss in 268 (13.5%), poor memory in 240 (12%), tingling and numbness in 200 (10%), and generalized weakness in 387 (19.4%) patients. Additionally, 541 (27.15%) patients had pigmentation of the nail bed, knuckles, oral mucosa, and tongue, while 237 (10.81%) suffered from hypertension and ischemic heart disease. During the process of preparation of vegetarian and nonvegetarian food, there is a 30-48% reduction in vitamin content. Supplementation of vitamin by adding table salt to food on a plate at the time of eating improves the vitamin level in the blood. CONCLUSION: In the absence of laboratory investigations in rural settings, clinical signs and symptoms are helpful in detecting B12 deficiency. Directly adding vitamin powder, similar to table salt, to cooked food on the plate improved blood vitamin levels.

Vitamin B12 Metabolism: A Network of Multi-Protein Mediated Processes.

The water-soluble vitamin, vitamin B12, also known as cobalamin, plays a crucial role in cellular metabolism, particularly in DNA synthesis, methylation, and mitochondrial functionality. Its deficiency can lead to hematological and neurological disorders; however, the manifestation of these clinical outcomes is relatively late. It leads to difficulties in the early diagnosis of vitamin B12 deficiency. A prolonged lack of vitamin B12 may have severe consequences including increased morbidity to neurological and cardiovascular diseases. Beyond inadequate dietary intake, vitamin B12 deficiency might be caused by insufficient bioavailability, blood transport disruptions, or impaired cellular uptake and metabolism. Despite nearly 70 years of knowledge since the isolation and characterization of this vitamin, there are still gaps in understanding its metabolic pathways. Thus, this review aims to compile current knowledge about the crucial proteins necessary to efficiently accumulate and process vitamin B12 in humans, presenting these systems as a multi-protein network. The epidemiological consequences, diagnosis, and treatment of vitamin B12 deficiency are also highlighted. We also discuss clinical warnings of vitamin B12 deficiency based on the ongoing test of specific moonlighting proteins engaged in vitamin B12 metabolic pathways.

Association of maternal and cord vitamin B12 levels with anthropometry in term neonates born to malnourished mothers in coastal South India.

Background: Malnourished pregnant women are at increased risk of micronutrient deficiency. We assessed the vitamin B12 status in both malnourished and normally nourished pregnant women and their neonates. Additionally, we studied the association between maternal B12 levels, cord B12 levels and neonatal anthropometry. Methods: This cross-sectional study enrolled 63 malnourished and 63 normally nourished mothers and neonates. Maternal and cord blood samples were collected at the time of delivery for estimation of vitamin B12 levels. Maternal and cord vitamin B12 levels were compared using the Mann-Whitney U test. Neonatal anthropometry was correlated with maternal and cord B12 levels using Spearman's correlation. Data were analyzed using SPSS version 25. Results: Mean maternal age was 26.58 yrs. The median cord B12 levels were lower than the maternal B12 levels. Maternal B12 levels showed a strong positive correlation with cord B12 levels (rho = 0.879; p < 0.001). Maternal (p < 0.001) and cord (p < 0.001) vitamin B12 levels were significantly lower in the malnourished group than in the normally nourished group. In malnourished group, 66.8% mothers and 95.2% neonates were Vitamin B12 deficient, whereas 1.5% mothers and 4.7% neonates were vitamin B12 deficient in normally nourished group. In the malnourished group, maternal B12 levels were positively correlated with birth weight (rho 0.363, p = 0.003) and length (rho 0.330, p =0.008), whereas cord B12 levels were positively correlated with birth weight in the normally nourished group. (rho 0.277 p= 0.028). Conclusion: High rates of vitamin B12 deficiency were observed in malnourished mothers and neonates. There was a positive correlation between birth weight, length, and maternal vitamin B12 levels in malnourished mothers. These findings emphasize the need to address maternal malnutrition and vitamin B12 deficiency to improve neonatal health.

Cerebral Venous Sinus Thrombosis Secondary to Vitamin B12 Deficiency - A Case Series with Emphasis on Food Fortification.

The etiology of cerebral venous sinus thrombosis (CVST) is multifactorial. Although many acquired and genetic factors have been recognized as risk factors, hyperhomocysteinemia (hHcy) is independently associated with CVST. We describe three cases of CVST in this case series. All of them presented with headache. Two patients had papilledema and visual disturbances. On evaluation, there was CVST, and prothrombotic workup showed hHcy. In addition, two of them reported very low Vitamin B12 levels. All of them were treated with low-molecular-weight heparin followed by oral anticoagulation and Vitamin B6, B9, and B12 supplements. All of them responded to treatment, and follow-up imaging studies in two of them showed resolution of thrombosis. hHcy should be considered in the evaluation of CVST, especially in the setting of a pure vegetarian diet. Fortification of the diet with Vitamin B12 may be considered the majority of Indians consume predominantly vegetarian food.

RésuméL'étiologie de la thrombose veineuse cérébrale (CVST) est multifactorielle. Bien que de nombreux facteurs acquis et génétiques aient été reconnus comme facteurs de risque, l'hyperhomocystéinémie (hHcy) est indépendamment associée à la CVST. Nous décrivons trois cas de CVST dans cette série de cas. Tous présentaient des maux de tête. Deux patients avaient un oedème papillaire et des troubles visuels. Lors de l'évaluation, il y avait une CVST et le bilan prothrombotique montrait une hHcy. De plus, deux d'entre eux ont rapporté des niveaux très bas de vitamine B12. Tous ont été traités avec de l'héparine de bas poids moléculaire suivie d'une anticoagulation orale et de suppléments de vitamines B6, B9 et B12. Tous ont répondu au traitement, et des études d'imagerie de suivi chez deux d'entre eux ont montré une résolution de la thrombose. L'hHcy doit être envisagée dans l'évaluation de la (CVST), en particulier dans le contexte d'un régime purement végétarien. La fortification de l'alimentation avec de la vitamine B12 peut être envisagée car la majorité des Indiens consomment principalement des aliments végétariens.

Vitamin B12 Deficiency in Clinical Practice-Proceedings of the International B12 Conference, June 2023, Rotterdam.

This supplement of the Food and Nutrition Bulletin is dedicated to the proceedings of "the International B12 Conference in Clinical Practice," held in Rotterdam in June 2023. The conference brought together physicians, scientists, patient groups, and health care professionals with substantial expertise in diagnosing and treating vitamin B12 deficiency from many universities around the world. With a collective commitment to advancing clinical practice and improving patient outcomes, this event was instrumental in addressing the many complex and challenging aspects of vitamin B12 deficiency. The subjects explored at the conference ranged from the latest research findings to real-world case studies, spanning diverse medical disciplines, including pediatrics, obstetrics, neurology, internal medicine, gastroenterology, psychiatry, clinical chemistry, nutrition, public health, biomedical science, and nursing. The broad spectrum of disciplines reflects the multifaceted nature of vitamin B12 deficiency and underscores the necessity of a comprehensive and multidisciplinary approach to its diagnosis and treatment. This supplement aims to distill into a concise and accessible format the knowledge shared by stimulating and provocative presentations at the B12 Conference and to make the information available for the broader scientific and health care community. The compendium bridges the insights generated at the conference and the wider audience of health care practitioners, researchers, and policymakers who recognize the urgency of addressing the critical public health concerns surrounding vitamin B12 deficiency.

Plain language title Vitamin B12 Deficiency in Clinical Practice: Proceedings of an International B12 Conference Plain language summary This supplement focuses on vitamin B12, a crucial micronutrient essential for overall human health. It summarizes the proceedings of the "International B12 Conference in Clinical Practice," held in June 2023 in Rotterdam. The conference gathered experts from various fields, including physicians, scientists, patient groups, and health care professionals, to address the complexities of diagnosing and treating vitamin B12 deficiency. The content covers various topics, from the latest research findings to real-world case studies spanning diverse medical disciplines. The aim is to distill the conference's knowledge into an accessible format for the broader scientific and health care community. The supplement emphasizes the need for a comprehensive and multidisciplinary approach to address Vitamin B12 deficiency by bringing together insights from different disciplines. The manuscripts within the supplement delve into the intricacies of vitamin B12 deficiency offering a synthesis of research findings, clinical insights, and innovative approaches to diagnosis and treatment. The goal is to inspire further research, inform clinical practice, and ultimately improve patient care in the critical areas of nutrition and health care. The supplement expresses gratitude to conference contributors, attendees, and supporters who made the event and publication possible. It aims to contribute to preventing or treating B12 deficiency and improving patients' health and well-being. Whether at the beginning or end of life and all ages in between, addressing B12 deficiency can significantly enhance global health and quality of life.

Long-Term Proton Pump Inhibitor-Acid Suppressive Treatment Can Cause Vitamin B12 Deficiency in Zollinger-Ellison Syndrome (ZES) Patients.

Whether the long-term treatment of patients with proton pump inhibitors (PPIs) with different diseases [GERD, Zollinger-Ellison syndrome (ZES), etc.] can result in vitamin B12 (VB12) deficiency is controversial. In this study, in 175 patients undergoing long-term ZES treatment with anti-acid therapies, drug-induced control acid secretory rates were correlated with the presence/absence of VB12 deficiency, determined by assessing serum VB12 levels, measurements of VB12 body stores (blood methylmalonic acid (MMA) and total homocysteine[tHYC]), and other features of ZES. After a mean of 10.2 yrs. of any acid treatment (5.6 yrs. with PPIs), 21% had VB12 deficiency with significantly lower serum and body VB12 levels (p < 0.0001). The presence of VB12 deficiency did not correlate with any feature of ZES but was associated with a 12-fold lower acid control rate, a 2-fold higher acid control pH (6.4 vs. 3.7), and acid control secretory rates below those required for the activation of pepsin (pH > 3.5). Over a 5-yr period, the patients with VB12 deficiency had a higher rate of achlorhydria (73% vs. 24%) and a lower rate of normal acid secretion (0% vs. 49%). In conclusion, in ZES patients, chronic long-term PPI treatment results in marked acid hyposecretion, resulting in decreased serum VB12 levels and decreased VB12-body stores, which can result in VB12 deficiency.

Vitamin B12-Related Biomarkers.

BACKGROUND: Adult vitamin B12 (B12) deficiency may present itself with nonspecific mainly neurological symptoms, and thus plasma biomarkers are often judged to be of major importance in the further diagnostic process. Four biomarkers are of special relevance: total B12, holotranscobalamin (the part of B12 bound to the active transport protein, transcobalamin, also named holoTC or active B12) and the 2 so-called metabolic markers that accumulate if B12 is lacking, methylmalonic acid (MMA) and homocysteine. OBJECTIVE: This article briefly reviews the inherent limitation of biomarkers, discusses its use in establishing the diagnosis and cause of B12 deficiency, and when following or discontinuing treatment with B12. METHODS: The review is based on published papers, but also on knowledge gained from working within the area. CONCLUSION: It is concluded that a combination of a B12 and a metabolic marker, for example, total B12 and MMA, may prove most useful in daily practice. An unexpectedly high level of total B12 is most often of no clinical importance, though sometimes related to the presence of underlying cancer. Measurement of total B12 is of limited value in patients on treatment with pharmacological doses of B12 but may be helpful if B12 treatment is discontinued.

Plain language titleVitamin B12-Related Blood TestsPlain language summaryBlood-testing is considered an important part of the diagnostic procedure in patients suspected to suffer from B12 deficiency. A deficiency is supported by a low level of plasma B12, and confirmed by a high level of methylmalonic acid, judged according to age and kidney function. Alternatively, a high level of homocysteine may support the diagnosis. Treatment of B12 deficiency is mainly guided by improvement of symptoms, with a very limited need for further blood testing. If B12-treatment is discontinued, B12 status should be judged every 6 months for approximately 2 years to detect a possible reoccurrence of a deficient state. An unexpected high level of plasma B12 is most often of no clinical implication.

Vitamin B12 Deficiency in Children and Adolescents: A Case for Revised Diagnostic Parameters.

BACKGROUND: Vitamin B12 deficiency is commonly diagnosed using thresholds developed for adults, yet emerging evidence indicates these levels may not be appropriate for children and adolescents. This misalignment can lead to underdiagnosis in younger populations, with potential long-term health implications. CASE SUMMARY: Chief Complaint: The 17-year-old female patient experienced severe fatigue, menstrual irregularities, psychological distress, and neurological symptoms over several years. The 13-year-old male patient had behavioral changes, gastrointestinal complaints, and sensory disturbances from an early age.Diagnosis: Both adolescents displayed B12 levels that were considered low-normal based on adult thresholds, complicating their diagnostic processes. Their diverse and atypical symptomatology required a comprehensive review of their medical and family histories, clinical symptoms, and risk factors.Intervention: Treatment included administration of hydroxocobalamin injections, complemented by dietary adjustments.Outcome: Both patients responded well to the treatment, showing significant improvements in their symptoms and overall quality of life. CONCLUSION: The main takeaway from these cases is the importance of tailoring diagnostic adequate thresholds and treatment plans to the pediatric population to address and manage B12 deficiency effectively. This approach can significantly enhance patient outcomes and prevent the progression of potentially severe complications in later life.

Plain language titleRevisiting Diagnostic Criteria for Vitamin B12 Deficiency in Children and Adolescents, a Case ReportPlain language summaryVitamin B12 deficiency is surprisingly common in kids and teenagers, but the problem is, only adult standards are available to diagnose it. Research shows that healthy children can have much different B12 levels than adults, meaning some kids with a deficiency might not get the help they need quickly. We share stories of 2 teenagers who suffered from B12 deficiency with very different symptoms, from extreme tiredness to mood changes and stomach issues. These cases show that diagnosing B12 deficiency can be difficult, especially with symptoms that don't fit the usual pattern. However, once they were properly diagnosed and treated adequate, these young people saw significant improvements in their health. These cases highlight the need for new standards tailored to children, to better identify and treat B12 deficiency early on, improving their quality of life.

Vitamin B12 Deficiency-Induced Neuropathy and Cognitive and Motor Impairment in the Elderly: A Case Study.

Vitamin B12 deficiency can present with a variety of neurological and cognitive symptoms. Especially in elderly patients, vitamin B12 deficiency can be easily overlooked because symptoms may be attributed to comorbid conditions or solely to the aging process. In this case study, we present two patients, a 71-year-old man and a 74-year-old female, with vitamin B12 deficiency. The male patient had a history of (partial) resection of the ileum/jejunum/colon because of intestinal ischemia. The female patient had a history of hypothyroidism, type 2 diabetes with complications (including peripheral neuropathy), mitochondrial myopathy, and chronic lymphocytic leukemia. Both patients presented with severe fatigue, cognitive impairment, and impaired walking. Next to this, the male patient suffered from depressive symptoms and mild disorientation, and the female patient experienced neuropathic pain. She also mentioned a positive family history for B12 deficiency. The first patient had normal to high B12 levels because he was already on B12 injections (once every three weeks) because of an earlier diagnosed B12 deficiency. The female patient had B12 levels within normal range (holotranscobalamin 54 pmol/L) and her diagnosis was confirmed by elevated homocysteine and methylmalonic acid levels. Treatment with frequent hydroxocobalamin injections and other supplements significantly improved their cognitive, emotional, and motor functions. These cases underscore the need for a high level of clinical suspicion in elderly patients, also in cases of normal B12 levels but with clinical signs of deficiency and a positive risk factor, such as stomach or small bowel surgery or positive family history.

Plain language titleA case study of two elderly patients with vitamin B12 deficiency and neurological and cognitive complaintsPlain language summaryVitamin B12 deficiency in elderly patients can be easily overlooked as symptoms can also be caused by other age-related diseases or the aging process. In our article we present two elderly patients, a 71-year-old male and a 74-year-old female, with neurological complaints, such as severe fatigue, cognitive decline, and walking impairment. The male patient had a history of small bowel surgery, and the female patient mentioned that she had several siblings with B12 deficiency. Additionally, the male patient suffered from depressive symptoms and mild disorientation, and the female had severe pain in her legs. The male patient already received B12 injections because of an earlier B12 diagnosis, but with a relatively low frequency. The B12 levels of the female patients were within the normal range. However, her diagnoses could be confirmed with additional laboratory measurements, such as homocysteine and methylmalonic acid. Treatment with frequent B12 injections and other supplements significantly improved their cognitive, emotional, and motor functions. Our study shows that clinicians should carefully consider the possibility of B12 deficiency in elderly patients with cognitive and neurological complaints, also in patients with B12 levels within the normal range, but with risk factors such as family members with B12 deficiency or conditions that may impair the vitamin B12 uptake, such as previous stomach or small bowel surgery.

Lack of Clinical Evidence Regarding the Guidelines for Vitamin B12 Deficiency: An Analysis From Literature and Recommendations From Clinical Practice.

BACKGROUND: Vitamin B12 deficiency is a critical medical condition that, if left untreated, can lead to severe symptoms and potentially serious and life-threatening complications. Clinical guidelines are designed to provide a standardized approach to diagnosis and treatment, aiming for consistency and effectiveness. However, it is well-established that not all patients fit into general guidelines. OBJECTIVE: To investigate the clinical relevance of the submitted research to support these protocols for diagnosing and treating a B12 deficiency. APPROACH: Conducting a literature review of the references focused and used on diagnosing and treating vitamin B12 deficiency in adults and children. RESULTS: No robust clinical trial nor RCT has been found to back up the current protocols. The research used is primarily based on assumptions rather than solid clinical evidence. CONCLUSION: Existing guidelines for vitamin B12 deficiency need to be significantly revised and improved through clinical research, clinical experience by experts in the field with input from patient groups worldwide.

Plain language titleAnalyzing the Lack of Research on Vitamin B12 Deficiency Guidelines: Insights from Studies and Clinical AdvicePlain language summaryThis study dives into Vitamin B12 deficiency, stressing its serious health impacts and potential life-threatening complications when not treated. The study aims to investigate the scientific articles supporting these guidelines and their clinical relevance, conducting an in-depth analysis of literature references. The manuscript investigates and criticizes current guidelines for B12 deficiency, pointing out 4 key issues reported by patients and clinicians worldwide. The results are grouped into 4 sections: Maintenance Dose Protocol: The study questions the adequacy of maintenance doses every few months, highlighting a lack of clinical evidence and challenging the idea of sufficient liver stores. Oral Supplementation Protocol: The effectiveness of oral supplements is questioned due to inconclusive trials, focusing on raising blood values rather than assessing actual clinical outcomes. Diagnosing B12 Deficiency in Children: Guidelines neglect B12 deficiency in children despite significant differences in B12 levels between adults and healthy kids, potentially leading to underdiagnosis and unnecessary suffering. Delay in Diagnosis and Treatment: Factors like a lack of awareness and diverse symptoms contribute to delays, emphasizing the ongoing challenge of standardizing B12 assays. In the discussion, the manuscript argues that awareness of guidelines is low, and evidence-based guidelines may lack practical relevance. It suggests a significant revision of guidelines based on robust clinical evidence, advocating for personalized treatment, patient monitoring tools, controlled trials, and age-related healthy levels. Recognizing diverse patient needs and implementing individualized therapies are crucial for improving care for those with vitamin B12 deficiency, emphasizing the importance of early recognition and intervention.

Development of a Vitamin B12 Deficiency Patient-Reported Outcome Measure for Clinical Practice and Research.

BACKGROUND: It is difficult to recognize vitamin B12 deficiency and to evaluate the effect of B12 treatment due to a broad range of variable clinical symptoms overlapping with other diseases and diagnostic biomarkers that quickly normalize during treatment. This poses a risk of delay in diagnosis and a challenge to uniformly monitor the effect of B12 treatment. There is a need for a new clinical outcome measure suitable for clinical practice and clinical evaluation studies. OBJECTIVE: To develop a Patient-Reported Outcome Measure (PROM) which measures the severity of vitamin B12 deficiency symptoms. METHODS: The B12 PROM was developed by (1) gathering input from experts and literature review to define a construct and develop a conceptual model, (2) processing input from health care providers, scientists, and patients to develop items and response options, and (3) improving items based on the feedback from laypersons, test interviews, semi-structured cognitive interviews with patients, and forward and backward translation (ENG-NL). RESULTS: The B12 PROM includes 62 items grouped into 8 categories of symptoms related to vitamin B12 deficiency (General, Senses, Thinking, In limbs and/or face, Movement, Emotions, Mouth & Abdomen, Urinary tract & Reproductive organs). Cognitive interviews demonstrated good comprehensibility and comprehensiveness. CONCLUSIONS: This study is the first step in the development of a disease-specific PROM for vitamin B12 deficiency to measure the burden of symptoms. Further validation and reliability testing are necessary before the PROM can be applied in clinical practice and research.

Plain language titleDevelopment of a Vitamin B12 Deficiency Questionnaire for Clinical Practice and ResearchPlain language summaryThis study is the first step in the development of a questionnaire for vitamin B12 deficiency to measure the severity of vitamin B12 deficiency symptoms. The questionnaire includes 62 items grouped into 8 categories of symptoms related to vitamin B12 deficiency (General, Senses, Thinking, In limbs and/or face, Movement, Emotions, Mouth & Abdomen, Urinary tract & Reproductive organs). Interviews with patients demonstrated good comprehensibility and comprehensiveness of the questionnaire. Further testing is necessary before the questionnaire can be applied in clinical practice and research.

Causes and Risk Factors of Vitamin B12 Deficiency at the Bookends of Life, From Infancy to Old Age.

The causes and risk factors of vitamin B12 deficiency are many and varied. Importantly, they vary considerably across the lifespan, from infancy to old age. The complexity of the physiology of vitamin B12 bespeaks the myriad of possible causes of deficiency and possible disruptions of its functional integrity. These lead ultimately to the pathobiological effects witnessed in deficiency of this fascinating micronutrient. This brief overview of the multiplicity of mechanisms that can result in vitamin B12 deficiency, and the panoply of its manifestations explores the underlying reasons for the protean presentations of the disease. As the human organism progresses through the chronology and milestones of age, various susceptibility factors arise resulting from the interplay of environmental and genetic factors. Acting independently and in concert, these factors produce the common denominator of vitamin B12 deficiency. However, the rate at which such deficiency develops and the way in which it presents clinically vary widely, subject to such influences as genetic variability, end-organ susceptibility, and concomitant micronutrient status. Some examples of unusual cases of vitamin B12 deficiency are described. Much has been learned about the last of the numbered vitamins in almost a century. Much yet remains to be discovered.

A Brief Overview of the Diagnosis and Treatment of Cobalamin (B12) Deficiency.

BACKGROUND: An increasing number of adult individuals are at risk of vitamin B12 deficiency, either from reduced nutritional intake or impaired gastrointestinal B12 absorption. OBJECTIVE: This study aims to review the current best practices for the diagnosis and treatment of individuals with vitamin B12 deficiency. METHODS: A narrative literature review of the diagnosis and treatment of vitamin B12 deficiency. RESULTS: Prevention and early treatment of B12 deficiency is essential to avoid irreversible neurological consequences. Diagnosis is often difficult due to diverse symptoms, marked differences in diagnostic assays' performance and the unreliability of second-line biomarkers, including holo-transcobalamin, methylmalonic acid and total homocysteine. Reduced dietary intake of B12 requires oral supplementation. In B12 malabsorption, oral supplementation is likely insufficient, and parenteral (i.e. intramuscular) supplementation is preferred. There is no consensus on the optimal long-term management of B12 deficiency with intramuscular therapy. According to the British National Formulary guidelines, many individuals with B12 deficiency due to malabsorption can be managed with 1000 µg intramuscular hydroxocobalamin once every two months after the initial loading. Long-term B12 supplementation is effective and safe, but responses to treatment may vary considerably. Clinical and patient experience strongly suggests that up to 50% of individuals require individualized injection regimens with more frequent administration, ranging from daily or twice weekly to every 2-4 weeks, to remain symptom-free and maintain a normal quality of life. 'Titration' of injection frequency based on measuring biomarkers such as serum B12 or MMA should not be practiced. There is currently no evidence to support that oral/sublingual supplementation can safely and effectively replace injections. CONCLUSIONS: This study highlights the interindividual differences in symptomatology and treatment of people with B12 deficiency. Treatment follows an individualized approach, based on the cause of the deficiency, and tailored to help someone to become and remain symptom-free.

Plain language titleDiagnosis and Treatment of Vitamin B12 DeficiencyPlain language summaryThe number of people who are at risk of developing a deficiency of vitamin B12 is steadily increasing. B12 deficiency can develop when people consume too few B12-containing foods of animal origin, or when they develop a form of B12 malabsorption. B12 deficiency can lead to serious complications so prevention and early treatment are essential. Diagnosing B12 deficiency can be challenging: the symptoms vary from patient to patient, and the methods used to measure B12 in the blood, or certain biomarkers associated with B12 metabolism, such as holo-transcobalamin, methylmalonic acid, and total homocysteine are unreliable. When people do not consume enough B12-containing foods, supplementation with B12 tablets is needed. In the case of B12 malabsorption, intramuscular injections of B12 are mandatory. The usual treatment with B12 is starting with injections of 1000 µg hydroxocobalamin twice weekly or on every other day for a period of up to 5 weeks or longer, until all symptoms have disappeared, and thereafter, the frequency of injections is gradually reduced. There is, however, a large group of people who require more frequent administration to become and remain symptom-free: this may range from daily or twice weekly to every 2 to 4 weeks.

Vitamin B12 and Age-Related Cognitive Decline-Dementia and "Alzheimer's Disease".

This article is a commentary on the role of vitamin B12 in age-related cognitive decline, with a meta-commentary on the misuse of the term "Alzheimer's Disease." The article describes the historical origins of the term "Alzheimer's Disease" and argues that the term should be restricted to a narrower segment of the age-related dementia spectrum. The article also outlines the role of vitamin B12 in age-related cognitive decline and outlines the rationale for the treatment of B12 deficiency to address a potentially reversible factor in cognitive decline.

Dermatological Conundrum: Puzzling Pigmentation in Vitamin B12 Deficiency and Addison's Disease.

We report a case series of two patients who had similar skin pigmentation but were caused by vitamin B12 deficiency and Addison's disease. We further discuss the pathophysiology of skin hyperpigmentation in both of these disorders and the response to treatment. Our case report highlights the importance of the identification of simple bedside clinical signs to diagnose reversible causes of skin pigmentation.

Defining Optimal Cobalamin Status for Neonates and Infants.

BACKGROUND: An optimal cobalamin status is necessary for normal neurodevelopment. OBJECTIVE: To give a description of the epidemiology, pathophysiology and diagnostic challenges related to cobalamin insufficiency in neonates and infants in order to prevent its occurence. RESULTS: Inadequate cobalamin status is prevalent among neonates and young infants, due to a high prevalence of maternal cobalamin deficiency, exclusive breastfeeding for extended periods and late introduction of animal food. Cobalamin insufficiency is associated with delayed neurodevelopment and subtle clinical symptoms like feeding difficulties, regurgitations and constipation in young infants. Early diagnosis and treatment of impaired cobalamin status is important to prevent neurologic damage. CONCLUSION: Clinical suspicion of cobalamin insufficiency in infants should infer immediate biochemical testing and a plasma total homocysteine > 5.0 µmol/L indicate cobalamin insufficiency in need of intramuscular treatment with hydroxycobalamin, followed by introduction of animal food after 4 months of age.

Plain language titleVitamin B12 Is Important for Normal Development in Young ChildrenPlain language summaryVitamin B12, also called cobalamin, is found only in animal-sourced food. As low-meat, vegetarian, and vegan diets are increasingly popular in Western countries, vitamin B12 deficiency has become common, also in pregnant women and babies. Vitamin B12 status is essential for normal development and adequate levels of this vitamin is particularly important during pregnancy and the first years of life. In pregnancy, vitamin B12 is transferred from the mother to the fetus, so the baby has a store of this vitamin at birth. However, if the mother has vitamin B12 deficiency or the baby is born premature or with a low birth weight, the vitamin store may be insufficient and the baby may develop vitamin B12 deficiency. Maternal vitamin B12 status is important as long as the baby is exclusively breastfed. Breast milk contains vitamin B12, but the concentration decreases after 4 to 6 weeks and may be too low to support the baby until animal-sourced foods are introduced. The vitamin B12 content in formula milk is higher than in breast milk, and vitamin B12 deficiency is more common in exclusively breastfed babies. Vitamin B12 deficiency is associated with diffuse symptoms in small babies and may be difficult to detect, and the diagnosis have a mean delay of 4 months in this age-group. Typical symptoms are regurgitations or spitting up, constipation, problems with feeding and swallowing, and delayed psychomotor development. Suspicion of vitamin B12 insufficiency in babies should prompt immediate biochemical testing. Plasma total homocysteine is a metabolic marker of vitamin B12 status and can be measured in a blood sample from the baby. A level >5.0 µmol/L indicates probable vitamin B12 insufficiency and the baby should receive vitamin B12 supplementation, followed by introduction of animal-sourced foods at 3 to 4 months of age.

Indicators of Cobalamin Status During Pregnancy, Pregnancy Outcome and Long-Term Effects on Offspring Health.

BACKGROUND: Little attention has been given to prenatal cobalamin insufficiency in settings where dietary cobalamin intake is presumed adequate, such as populations with habitual intake of foods from animal sources. RESULTS: However, low cobalamin status in women of fertile age has been reported in Europe, United States, and Canada. In India, where cobalamin deficiency is highly prevalent, it has been associated with an increased risk of miscarriage, intrauterine growth retardation, as well as insulin resistance and lower neurodevelopment scores in the offspring. Low cobalamin status in pregnancy has been associated with similar outcomes as those reported in the Indian studies although the evidence is scant and conflicting. CONCLUSIONS: Consideration should be given to maternal cobalamin status in the context of prevention of adverse pregnancy outcomes as well as cobalamin insufficiency both in the mother and the offspring during lactation. Further attention is now justified with the increasing tendency toward plant-based diets. Reference intervals for cobalamin status during each trimester of pregnancy are needed and further investigation of the long-term conse-quences of low cobalamin status during pregnancy for health and development in the offspring is warranted.

Plain language titleInadequate cobalamin status during critical periods of growth and development can have negative consequences on maternal and childhood health.

A Systematic Review of Symptoms of Pernicious Anemia.

BACKGROUND: Pernicious anemia (PA) is a type of macrocytic anemia caused by autoimmune gastritis. To facilitate timely diagnosis and treatment of PA there is a pressing need for improved understanding among Healthcare providers of the condition's symptoms and diagnostic criteria. OBJECTIVE: This systematic review aims to extend existing clinical knowledge on the presentation of PA by determining which symptoms and clinical complications are reported in published adult case studies. METHODS: Relevant studies were identified through electronic searches of PsycINFO, Embase, and MEDLINE, via OvidSP. During data extraction symptoms were categorized according to the International Classification of Diseases and were grouped based on frequency. RESULTS: Symptoms were documented for 103 adults with a diagnosis of PA; the most frequent symptoms were fatigue (55%), loss of sensation in limbs (32%), excessive weight loss (27%), and a sore tongue (23%). CONCLUSIONS: This review highlights the diverse symptomology of adults who are diagnosed with PA. Most symptoms documented in case studies are consistent with the core signs of B12 and folate deficiencies. Research is needed to identify if there are common clusters of PA symptoms that can be used as prompts for diagnostic testing in patients with suspected B12 deficiency.

Plain language titleA Review of Symptoms of Pernicious AnemiaPlain language summaryThis study reviewed case studies that have been written about adults with pernicious anemia, it has documented the frequency of the core symptoms and the impact these have on health.