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Cleveland Clinic Journal of Medicine Mar 2020Megaloblastic anemia causes macrocytic anemia from ineffective red blood cell production and intramedullary hemolysis. The most common causes are folate (vitamin B)... (Review)
Review
Megaloblastic anemia causes macrocytic anemia from ineffective red blood cell production and intramedullary hemolysis. The most common causes are folate (vitamin B) deficiency and cobalamin (vitamin B) deficiency. Megaloblastic anemia can be diagnosed based on characteristic morphologic and laboratory findings. However, other benign and neoplastic diseases need to be considered, particularly in severe cases. Therapy involves treating the underlying cause-eg, with vitamin supplementation in cases of deficiency, or with discontinuation of a suspected medication.
Topics: Adolescent; Aged; Anemia, Megaloblastic; Avitaminosis; Diagnosis, Differential; Dietary Supplements; Female; Folic Acid; Folic Acid Deficiency; Humans; Male; Severity of Illness Index; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 32127439
DOI: 10.3949/ccjm.87a.19072 -
Vitamins and Hormones 2022Vitamin B12 is assimilated and transported by complex mechanisms that involve three transport proteins, intrinsic factor (IF), haptocorrin (HC) and transcobalamin (TC)... (Review)
Review
Vitamin B12 is assimilated and transported by complex mechanisms that involve three transport proteins, intrinsic factor (IF), haptocorrin (HC) and transcobalamin (TC) and their respective membrane receptors. Vitamin deficiency is mainly due to inadequate dietary intake in vegans, and B12 malabsorption is related to digestive diseases. This review explores the physiology of vitamin B12 absorption and the mechanisms and diseases that produce malabsorption. In the stomach, B12 is released from food carrier proteins and binds to HC. The degradation of HC by pancreatic proteases and the pH change trigger the transfer of B12 to IF in the duodenum. Cubilin and amnionless are the two components of the receptor that mediates the uptake of B12 in the distal ileum. Part of liver B12 is excreted in bile, and undergoes an enterohepatic circulation. The main causes of B12 malabsorption include inherited disorders (Intrinsic factor deficiency, Imerslund-Gräsbeck disease, Addison's pernicious anemia, obesity, bariatric surgery and gastrectomies. Other causes include pancreatic insufficiency, obstructive Jaundice, tropical sprue and celiac disease, bacterial overgrowth, parasitic infestations, Zollinger-Ellison syndrome, inflammatory bowel diseases, chronic radiation enteritis of the distal ileum and short bowel. The assessment of B12 deficit is recommended in the follow-up of subjects with bariatric surgery. The genetic causes of B12 malabsorption are probably underestimated in adult cases with B12 deficit. Despite its high prevalence in the general population and in the elderly, B12 malabsorption cannot be anymore assessed by the Schilling test, pointing out the urgent need for an equivalent reliable test.
Topics: Adult; Aged; Anemia, Megaloblastic; Humans; Intrinsic Factor; Malabsorption Syndromes; Male; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 35337622
DOI: 10.1016/bs.vh.2022.01.016 -
Pediatrics in Review Apr 2018The published literature supports the high prevalence of supplement use in children and adolescents in the United States. Pediatricians today are faced with questions... (Review)
Review
The published literature supports the high prevalence of supplement use in children and adolescents in the United States. Pediatricians today are faced with questions from parents and patients about the benefits, safety, efficacy, and correct dose of vitamins and minerals. In this article, we review 7 vitamins with the most clinical relevance as judged by abundance in food, risks and symptoms of deficiency, and potential for toxicity. Specifically, we focus on possible clinical scenarios that can be indicative of nutritional deficiency. We synthesize and summarize guidelines from nutrition experts, various medical societies, the World Health Organization, and the American Academy of Pediatrics.
Topics: Adolescent; Avitaminosis; Breast Feeding; Child; Diet; Dietary Supplements; Humans; Infant; Pediatrics; Professional-Family Relations; Recommended Dietary Allowances; Risk Assessment; Risk Factors; Vitamins
PubMed: 29610425
DOI: 10.1542/pir.2016-0068 -
Muscle & Nerve Jul 2020Neuropathies associated with nutritional deficiencies are routinely encountered by the practicing neurologist. Although these neuropathies assume different patterns,... (Review)
Review
Neuropathies associated with nutritional deficiencies are routinely encountered by the practicing neurologist. Although these neuropathies assume different patterns, most are length-dependent, sensory axonopathies. Cobalamin deficiency neuropathy is the exception, often presenting with a non-length-dependent sensory neuropathy. Patients with cobalamin and copper deficiency neuropathy characteristically have concomitant myelopathy, whereas vitamin E deficiency is uniquely associated with a spinocerebellar syndrome. In contrast to those nutrients for which deficiencies produce neuropathies, pyridoxine toxicity results in a non-length-dependent sensory neuronopathy. Deficiencies occur in the context of malnutrition, malabsorption, increased nutrient loss (such as with dialysis), autoimmune conditions such as pernicious anemia, and with certain drugs that inhibit nutrient absorption. When promptly identified, therapeutic nutrient supplementation may result in stabilization or improvement of these neuropathies.
Topics: Anemia, Pernicious; Avitaminosis; Dietary Supplements; Humans; Nutritional Status; Peripheral Nervous System Diseases; Thiamine Deficiency; Vitamin B 12 Deficiency; Vitamins
PubMed: 31837157
DOI: 10.1002/mus.26783 -
The Medical Clinics of North America Mar 2017Vitamin B and folate deficiencies are major causes of megaloblastic anemia. Causes of B deficiency include pernicious anemia, gastric surgery, intestinal disorders,... (Review)
Review
Vitamin B and folate deficiencies are major causes of megaloblastic anemia. Causes of B deficiency include pernicious anemia, gastric surgery, intestinal disorders, dietary deficiency, and inherited disorders of B transport or absorption. The prevalence of folate deficiency has decreased because of folate fortification, but deficiency still occurs from malabsorption and increased demand. Other causes include drugs and inborn metabolic errors. Clinical features of megaloblastic anemia include anemia, cytopenias, jaundice, and megaloblastic marrow morphology. Neurologic symptoms occur in B deficiency, but not in folate deficiency. Management includes identifying any deficiency, establishing its cause, and replenishing B or folate parenterally or orally.
Topics: Anemia, Megaloblastic; Comorbidity; Folic Acid Deficiency; Humans; Metabolic Diseases; Nutrition Disorders; Prevalence; Vitamin B 12 Deficiency
PubMed: 28189172
DOI: 10.1016/j.mcna.2016.09.013 -
Annals of the New York Academy of... Aug 2021Thiamine is an essential water-soluble vitamin that plays an important role in energy metabolism. Thiamine deficiency presents many challenges to clinicians, in part due... (Review)
Review
Thiamine is an essential water-soluble vitamin that plays an important role in energy metabolism. Thiamine deficiency presents many challenges to clinicians, in part due to the broad clinical spectrum, referred to as thiamine deficiency disorders (TDDs), affecting the metabolic, neurologic, cardiovascular, respiratory, gastrointestinal, and musculoskeletal systems. Concurrent illnesses and overlapping signs and symptoms with other disorders can further complicate this. As such, TDDs are frequently misdiagnosed and treatment opportunities missed, with fatal consequences or permanent neurologic sequelae. In the absence of specific diagnostic tests, a low threshold of clinical suspicion and early therapeutic thiamine is currently the best approach. Even in severe cases, rapid clinical improvement can occur within hours or days, with neurological involvement possibly requiring higher doses and a longer recovery time. Active research aims to help better identify patients with thiamine-responsive disorders and future research is needed to determine effective dosing regimens for the various clinical presentations of TDDs. Understanding the clinical diagnosis and global burden of thiamine deficiency will help to implement national surveillance and population-level prevention programs, with education to sensitize clinicians to TDDs. With concerted effort, the morbidity and mortality related to thiamine deficiency can be reduced.
Topics: Age Factors; Beriberi; Combined Modality Therapy; Diagnosis, Differential; Disease Management; Disease Transmission, Infectious; Humans; Organ Specificity; Population Surveillance; Symptom Assessment; Thiamine; Thiamine Deficiency
PubMed: 33305487
DOI: 10.1111/nyas.14536 -
Journal of Evidence-based Medicine May 2021Pernicious 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... (Review)
Review
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.
Topics: Anemia, Pernicious; Humans; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 34015185
DOI: 10.1111/jebm.12435 -
Blood May 2017B deficiency is the leading cause of megaloblastic anemia, and although more common in the elderly, can occur at any age. Clinical disease caused by B deficiency usually... (Review)
Review
B deficiency is the leading cause of megaloblastic anemia, and although more common in the elderly, can occur at any age. Clinical disease caused by B deficiency usually connotes severe deficiency, resulting from a failure of the gastric or ileal phase of physiological B absorption, best exemplified by the autoimmune disease pernicious anemia. There are many other causes of B deficiency, which range from severe to mild. Mild deficiency usually results from failure to render food B bioavailable or from dietary inadequacy. Although rarely resulting in megaloblastic anemia, mild deficiency may be associated with neurocognitive and other consequences. B deficiency is best diagnosed using a combination of tests because none alone is completely reliable. The features of B deficiency are variable and may be atypical. Timely diagnosis is important, and treatment is gratifying. Failure to diagnose B deficiency can have dire consequences, usually neurological. This review is written from the perspective of a practicing hematologist.
Topics: Anemia, Megaloblastic; Anemia, Pernicious; Animals; Folic Acid; Humans; Intestinal Absorption; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 28360040
DOI: 10.1182/blood-2016-10-569186 -
Journal of Neurology, Neurosurgery, and... Dec 2023Nutritional peripheral neuropathies are a global problem, heavily influenced by geopolitical, cultural and socioeconomic factors. Peripheral neuropathy occurs most... (Review)
Review
Nutritional peripheral neuropathies are a global problem, heavily influenced by geopolitical, cultural and socioeconomic factors. Peripheral neuropathy occurs most frequently secondary to B-vitamin deficiencies, which is suspected to increase in years to come due to the popularity of vegan and vegetarian diets and increased use of bariatric surgery.This review will focus on the common B-vitamins for which a causal link to peripheral neuropathy is more established (vitamins B, B, B, B and B). We will review the historical human and animal data on which much of the clinical descriptions of vitamin deficiencies are based and summarise current available tools for accurately diagnosing a nutritional deficiency. We will also review recently described genetic diseases due to pathogenic variants in genes involved in B-vitamin metabolism that have helped to inform the phenotypes and potential causality of certain B-vitamins in peripheral neuropathy (B and B).Endemic outbreaks of peripheral neuropathy over the last two centuries have been linked to food shortages and nutritional deficiency. These include outbreaks in Jamaican sugar plantation workers in the nineteenth century (Strachan's syndrome), World War two prisoners of war, Cuban endemic neuropathy and also Tanzanian endemic optic neuropathy, which remains a significant public health burden today. An improved understanding of lack of which vitamins cause peripheral neuropathy and how to identify specific deficiencies may lead to prevention of significant and irreversible disability in vulnerable populations.
Topics: Animals; Humans; Peripheral Nervous System Diseases; Vitamin B Complex; Avitaminosis; Malnutrition; Thiamine; Vitamin A; Optic Nerve Diseases
PubMed: 37536924
DOI: 10.1136/jnnp-2022-329849 -
Indian Pediatrics Feb 2022The emerging literature on prevalence of vitamin D deficiency in India, prevention and treatment strategies of rickets, and extra-skeletal benefits of vitamin D suggest...
JUSTIFICATION
The emerging literature on prevalence of vitamin D deficiency in India, prevention and treatment strategies of rickets, and extra-skeletal benefits of vitamin D suggest the need for revising the existing guidelines for prevention and treatment of vitamin D deficiency in India.
OBJECTIVES
To review the emerging literature on vitamin D prevalence and need for universal vitamin D supplementation. To suggest optimum vitamin D therapy for treatment of asymptomatic and symptomatic vitamin D deficiency, and rickets. To evaluate the extra-skeletal health benefits of vitamin D in children.
PROCESS
A National consultative committee was formed that comprised of clinicians, epidemiologists, endocrinologists, and nutritionists. The Committee conducted deliberations on different aspects of vitamin D deficiency and rickets through ten online meetings between March and September, 2021. A draft guideline was formulated, which was reviewed and approved by all Committee members.
RECOMMENDATIONS
The group reiterates the serum 25-hydroxy vitamin D cutoffs proposed for vitamin D deficiency, insufficiency, and sufficiency as <12 ng/mL, 12-20 ng/mL and >20 ng/mL, respectively. Vitamin D toxicity is defined as serum 25OHD >100 ng/mL with hypercalcemia and/or hypercalciuria. Vitamin D supplementation in doses of 400 IU/day is recommended during infancy; however, the estimated average requirement in older children and adolescents (400-600 IU/day, respectively) should be met from diet and natural sources like sunlight. Rickets and vitamin D deficiency should be treated with oral cholecalciferol, preferably in a daily dosing schedule (2000 IU below 1 year of age and 3000 IU in older children) for 12 weeks. If compliance to daily dosing cannot be ensured, intermittent regimens may be prescribed for children above 6 months of age. Universal vitamin D supplementation is not recommended in childhood pneumonia, diarrhea, tuberculosis, HIV and non-infectious conditions like asthma, atopic dermatitis, and developmental disorders. Serum 25-hydroxy vitamin D level of >20 ng/mL should be maintained in children with conditions at high-risk for vitamin deficiency, like nephrotic syndrome, chronic liver disease, chronic renal failure, and intake of anticonvulsants or glucocorticoids.
Topics: Adolescent; Child; Cholecalciferol; Dietary Supplements; Humans; Pediatrics; Rickets; Vitamin D; Vitamin D Deficiency; Vitamins
PubMed: 34969941
DOI: No ID Found