Vitamin B12 Deficiency in Clinical Practice: Multisystem Manifestations, Diagnostics, and Treatment Approaches

Vitamin B₁₂ deficiency is a common interdisciplinary problem that can manifest itself not only in megaloblastic anemia, but also in neurological, cognitive, psychoemotional, gastrointestinal, and metabolic disorders. The article summarizes the materials of the webinar «The Many Faces of Vitamin B₁₂ Deficiency: A Multidisciplinary Discussion on Evidence and Clinical Practice», dedicated to modern approaches to the diagnosis and treatment of vitamin B₁₂ deficiency. The role of a complete blood count, vitamin B₁₂ and folate levels, markers of intraosseous hemolysis, and functional biomarkers — holotranscobalamin, methylmalonic acid, and homocysteine — is considered. Particular attention is paid to patients with neurological symptoms, the elderly, and patients who have been receiving metformin, levodopa, or GLP-1 receptor agonists for a long time. Treatment approaches should be individualized, taking into account the severity of symptoms, the cause of the deficiency, and the route of administration of the drug. The goal of therapy is not only to normalize laboratory parameters, but primarily to achieve clinical improvement and prevent potentially irreversible neurological consequences.