Patient presents with symptoms suggestive of vitamin B12 deficiency (ICD-10-CM code E53.8), including fatigue, weakness, and paresthesias.  The patient reports experiencing glossitis and difficulty with balance.  Physical examination reveals pallor and a smooth, red tongue.  Neurological examination demonstrates diminished vibratory sensation and decreased deep tendon reflexes.  Complete blood count (CBC) reveals macrocytic anemia with elevated mean corpuscular volume (MCV).  Peripheral blood smear shows macro-ovalocytes and hypersegmented neutrophils.  Serum vitamin B12 levels are confirmed to be low (less than 200 pgmL).  Differential diagnosis includes folate deficiency, pernicious anemia, and myelodysplastic syndromes.  Based on the patient's presentation, laboratory findings, and clinical picture, a diagnosis of vitamin B12 deficiency is made.  The patient's symptoms,  medical history, and risk factors for B12 deficiency, including dietary habits, malabsorption syndromes, and use of medications such as proton pump inhibitors, were reviewed. The plan includes intramuscular injections of cyanocobalamin (vitamin B12) supplementation to address the deficiency and regular monitoring of B12 levels, CBC, and neurological symptoms to assess treatment efficacy. Patient education regarding dietary sources of vitamin B12 and potential long-term complications of untreated B12 deficiency, such as peripheral neuropathy and cognitive impairment, was provided. Follow-up appointment scheduled to reassess clinical status and adjust treatment plan as needed.