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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 -
Archives of Pathology & Laboratory... Nov 2019Autoimmune gastritis (AG) is a corpus-restricted chronic atrophic gastritis associated with intrinsic factor deficiency, either with or without pernicious anemia.... (Review)
Review
CONTEXT.—
Autoimmune gastritis (AG) is a corpus-restricted chronic atrophic gastritis associated with intrinsic factor deficiency, either with or without pernicious anemia. Autoimmune gastritis is a microscopic disease because patients present with no or vague symptoms, and clinicians rarely find endoscopic changes. Autoimmune gastritis only becomes a clinical disease when pathologists diagnose it in gastric biopsies performed for a variety of clinical indications. Unfamiliarity with this disease can result in misdiagnosis of patients, and thus inadequate patient management.
OBJECTIVE.—
To review the pathogenesis, clinical features, diagnostic criteria, differential diagnoses, sequelae, and surveillance recommendations for AG.
DATA SOURCES.—
The sources of the study include a review of the pertinent literature for AG.
CONCLUSIONS.—
Autoimmune gastritis is an important disease characterized by a loss of oxyntic mucosa and presence of metaplastic epithelium and enterochromaffin-like cell hyperplasia. Awareness and proper diagnosis are critical to prevent mismanagement of patients.
Topics: Anemia, Pernicious; Autoimmune Diseases; Biopsy; Chronic Disease; Diagnosis, Differential; Diagnostic Errors; Epithelium; Gastritis, Atrophic; Humans; Hyperplasia; Intrinsic Factor; Metaplasia; Stomach
PubMed: 31661309
DOI: 10.5858/arpa.2019-0345-RA -
World Journal of Diabetes Jul 2021To date, metformin remains the first-line oral glucose-lowering drug used for the treatment of type 2 diabetes thanks to its well-established long-term safety and... (Review)
Review
To date, metformin remains the first-line oral glucose-lowering drug used for the treatment of type 2 diabetes thanks to its well-established long-term safety and efficacy profile. Indeed, metformin is the most widely used oral insulin-sensitizing agent, being prescribed to more than 100 million people worldwide, including patients with prediabetes, insulin resistance, and polycystic ovary syndrome. However, over the last decades several observational studies and meta-analyses have reported a significant association between long-term metformin therapy and an increased prevalence of vitamin B12 deficiency. Of note, evidence suggests that long-term and high-dose metformin therapy impairs vitamin B12 status. Vitamin B12 (also referred to as cobalamin) is a water-soluble vitamin that is mainly obtained from animal-sourced foods. At the cellular level, vitamin B12 acts as a cofactor for enzymes that play a critical role in DNA synthesis and neuroprotection. Thus, vitamin B12 deficiency can lead to a number of clinical consequences that include hematologic abnormalities (, megaloblastic anemia and formation of hypersegmented neutrophils), progressive axonal demyelination and peripheral neuropathy. Nevertheless, no definite guidelines are currently available for vitamin B12 deficiency screening in patients on metformin therapy, and vitamin B12 deficiency remains frequently unrecognized in such individuals. Therefore, in this "field of vision" article we propose a list of criteria for a cost-effective vitamin B12 deficiency screening in metformin-treated patients, which could serve as a practical guide for identifying individuals at high risk for this condition. Moreover, we discuss additional relevant topics related to this field, including: (1) The lack of consensus about the exact definition of vitamin B12 deficiency; (2) The definition of reliable biomarkers of vitamin B12 status; (3) Causes of vitamin B12 deficiency other than metformin therapy that should be identified promptly in metformin-treated patients for a proper differential diagnosis; and (4) Potential pathophysiological mechanisms underlying metformin-induced vitamin B12 deficiency. Finally, we briefly review basic concepts related to vitamin B12 supplementation for the treatment of vitamin B12 deficiency, particularly when this condition is induced by metformin.
PubMed: 34326945
DOI: 10.4239/wjd.v12.i7.916 -
Nutrients Apr 2022Pernicious anemia is still a neglected disorder in many medical contexts and is underdiagnosed in many patients. Pernicious anemia is linked to but different from... (Review)
Review
Pernicious anemia is still a neglected disorder in many medical contexts and is underdiagnosed in many patients. Pernicious anemia is linked to but different from autoimmune gastritis. Pernicious anemia occurs in a later stage of autoimmune atrophic gastritis when gastric intrinsic factor deficiency and consequent vitamin B deficiency may occur. The multifaceted nature of pernicious anemia is related to the important role of cobalamin, which, when deficient, may lead to several dysfunctions, and thus, the proteiform clinical presentations of pernicious anemia. Indeed, pernicious anemia may lead to potentially serious long-term complications related to micronutrient deficiencies and their consequences and the development of gastric cancer and type 1 gastric neuroendocrine tumors. When not recognized in a timely manner or when pernicious anemia is diagnosed with delay, these complications may be potentially life-threatening and sometimes irreversible. The current review aimed to focus on epidemiology, pathogenesis, and clinical presentations of pernicious anemia in an attempt to look beyond borders of medical specialties. It aimed to focus on micronutrient deficiencies besides the well-known vitamin B deficiency, the diagnostic approach for pernicious anemia, its long-term complications and optimal clinical management, and endoscopic surveillance of patients with pernicious anemia.
Topics: Anemia, Pernicious; Gastritis; Humans; Micronutrients; Precancerous Conditions; Stomach Neoplasms; Vitamin B 12; Vitamin B 12 Deficiency; Vitamins
PubMed: 35458234
DOI: 10.3390/nu14081672 -
Discovery Medicine 2019Pernicious anemia (PA), the commonest cause of cobalamin deficiency (CD) in the world, is an autoimmune disease of multifactorial origin and is characterized by chronic... (Review)
Review
Pernicious anemia (PA), the commonest cause of cobalamin deficiency (CD) in the world, is an autoimmune disease of multifactorial origin and is characterized by chronic atrophic gastritis (CAG) and defective absorption of cobalamin from the terminal ileum due to interference by the intrinsic factor (IF) antibodies. PA-related CD is a lengthy process, which if untreated, can lead to irreversible hematological and neurological sequelae. Although safe and effective therapy is available and the management of PA is straightforward, the diagnosis of PA can be extremely difficult to obtain due to myriad and diverse clinical presentations, frequently coexisting diseases, and limitations of currently available diagnostic tests. Diagnostic dilemmas may occur when PA patients present with normal or spuriously high serum cobalamin levels, dysplastic features of ring sideroblasts in the bone marrow (BM), hemolysis, and concomitant diseases such as iron deficiency or thalassemia. Herein, the author discusses an overview of diagnostic difficulties, with regards to morphological mimics, coexisting diseases, limitations of currently available tests, and how to diagnose PA in the era of imperfect laboratory tests.
Topics: Anemia, Pernicious; Autoantibodies; Biomarkers; Hematologic Tests; Humans
PubMed: 32053765
DOI: No ID Found -
Blood May 2020
Topics: Adult; Anemia, Pernicious; Female; Humans; Prognosis; Vitamin B 12; Vitamin B 12 Deficiency; Vitamin B Complex
PubMed: 32379881
DOI: 10.1182/blood.2020005344