A Brief Review on Vitamin B₁₂ Deficiency Looking at Some Case Study Reports in Adults

In the era of evidence-based medicine, the randomized clinical trial corresponds to the top step in the qualitative scale of the evidence available in the literature, while small series of cases or the description of individual cases occupy the last place. However, the latter represent an important part of clinical practice and have significantly influenced the evolution of medicine, contributing significantly to the advancement of scientific knowledge. Vitamin B₁₂ deficiency shares several common symptoms that affect several tissues and organs with health aliments, so its diagnosis could be unobvious for the broad array of its effects and investigation methods used. In this review, we focused our attention on some case reports related to the vitamin B₁₂ deficiency associated to anemia, neurologic disorders, and hyperhomocysteinemia. B₁₂ deficiency reversal is simply achieved by prompt therapy, even though it is not the same for several disorders.