Vitamin B12 deficiency | Folate deficiency | |
---|---|---|
Etiology | Lack of intrinsic factor: pernicious anemia Malabsorption: celiac disease, prior gastric or ileal surgery Dietary deficiency less common | Dietary deficiency: alcoholism, countries without food fortification Malabsorption: developed countries Increased demand: pregnancy, hemolytic anemia, eczema |
Clinical presentation | Hematologic findings: cytopenias Neuropsychiatric symptoms: paresthesias, decreased proprioception and vibratory sense, dementia, confusion | Hematologic findings: cytopenias |
Evaluation | Clinical history and physical examination: symptoms secondary to anemia and hemolysis, neurologic symptoms Laboratory testing: serum vitamin B12, methylmalonic acid, homocysteine, antiparietal cell and anti-intrinsic factor antibodies, serum gastrin Gastric biopsy for suspected pernicious anemia | Clinical history and physical examination: similar to vitamin В12 deficiency, except no neurologic symptoms Laboratory testing: serum folate, red blood cell folate, methylmalonic acid, homocysteine |
Differential diagnosis | Other macrocytic anemias without megaloblastic features: liver disease, thyroid dysfunction, alcohol abuse Myelodysplastic syndrome, acute myeloid leukemia Nitrous oxide exposure Medication effect | Other macrocytic anemias without megaloblastic features: liver disease, thyroid dysfunction, alcohol abuse Myelodysplastic syndrome, acute myeloid leukemia Medication effect |
Treatment | Parenteral vitamin В12 1-2 times per week until symptoms improve, then monthly High-dose oral vitamin B12 daily | Oral folate daily |
Monitoring and follow-up | Clinical follow-up for improvement of neurologic symptoms Monitor hematologic response: complete blood cell count Pernicious anemia: consider monitoring methylmalonic acid | Monitor hematologic response: complete blood cell count |