Clinical practice. Vitamin B12 deficiency

Division of Hematology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
New England Journal of Medicine (Impact Factor: 55.87). 01/2013; 368(2):149-60. DOI: 10.1056/NEJMcp1113996
Source: PubMed
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    • "The diagnosis of vitamin B12 deficiency can be done with initial testing of vitamin B12 assay [1]. Extremely low level (<100 pg per milliliter) is usually associated with clinical deficiency [1]. "
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    ABSTRACT: A 52-year-old male with no significant past medical history reports increasing generalized fatigue and weakness for the past 2 weeks. Physical examination reveals jaundice and pallor without organomegaly or lymphadenopathy. His hemoglobin was 5.9 g/dL with a mean corpuscular volume of 87.1 fL and elevated red blood cell distribution width of 30.7%. His liver function test was normal except for elevated total bilirubin of 3.7 mg/dL. Serum LDH was 701 IU/L, and serum haptoglobin was undetectable. Further investigation revealed serum vitamin B12 of <30 pg/mL with elevated methylmalonic acid and homocysteine level. In addition, serum ferritin and transferrin saturation were low. The patient was diagnosed with hemolytic anemia secondary to vitamin B12 deficiency with concomitant iron deficiency anemia.
    09/2013; 2013:708489. DOI:10.1155/2013/708489
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    • "The treatment of N2O abuse-induced vitamin B12 deficiency is similar to the treatment of pernicious anemia, and comprises 1 of 2 regimens: (1) intramuscular injections of 1,000 µg vitamin B12 (cyanocobalamin) daily for 1 week, followed by weekly injections for 4–8 weeks, and then monthly injections until clinical resolution; or (2) daily oral administration of 1,000–2,000 µg cyanocobalamin until clinical resolution [15]. "
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    ABSTRACT: Vitamin B12 deficiency causes skin hyperpigmentation, subacute combined degeneration of the spinal cord, and megaloblastic anemia. Although vitamin B12 deficiency rarely occurs in well-nourished, healthy, young people, nitrous oxide (N2O) intoxication is an important cause of vitamin B12 deficiency in this cohort. N2O, a colorless gas used as an anesthetic since the late 19th century because of its euphoric and analgesic qualities, is now used as a recreational drug and is available via the Internet and at clubs. Here, we describe the case of a 29-year-old woman presenting with skin hyperpigmentation as her only initial symptom after N2O abuse for approximately 2 years. N2O intoxication-induced vitamin B12 deficiency was diagnosed based on the skin pigmentation that had manifested over the dorsa of her fingers, toes, and trunk, coupled with myeloneuropathy of the posterior and lateral columns, a low serum vitamin B12 level, an elevated serum homocysteine level, and the N2O exposure revealed while establishing the patient's history. Symptoms improved significantly with vitamin B12 treatment. We recommend that dermatologists consider N2O intoxication-induced vitamin B12 deficiency as a potential cause of skin hyperpigmentation and myeloneuropathy of the posterior and lateral columns in young, otherwise healthy patients. Failure to recognize this presentation may result in inappropriate treatment, thus affecting patients' clinical outcomes.
    Case Reports in Dermatology 05/2013; 5(2):186-91. DOI:10.1159/000353623
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    ABSTRACT: Subclinical vitamin B12 deficiency is common in the elderly worldwide. We investigated the change of serum vitamin B12 concentration with aging and compared anthropometric data and clinical health indicators between normal (≥ 340 pg/mL) and low (< 340 pg/mL) serum vitamin B12 groups in 470 Korean women aged 65 years and over living in a rural area. Serum vitamin B12 concentration showed inverse correlation with age (r = -0.0992, p < 0.05). The normal B12 group showed significantly (p < 0.05) higher red blood cell count, hemoglobin, and hematocrit compared to the low B12 group, however, no difference in mean corpuscular volume was observed between the two groups. The normal B12 group showed significantly lower serum homocysteine concentration (p < 0.01) and prevalence of vitamin D (p < 0.01) or folate deficiency (p < 0.001). Bone mineral density (T-score) was significantly higher (p < 0.05) in the normal B12 group, compared with that in the low B12 group, and showed positive correlation (r = 0.1490, p < 0.01) with serum vitamin B12 concentration after adjusting for age, body weight, and body mass index. No differences in anthropometric data, physical activity, and smoking and drinking habits were observed between the two groups. In conclusion, it could be suggested that older female adults with normal serum vitamin B12 level would be less anemic and osteoporotic and more resistant to hyperhomocysteinemia associated chronic diseases than those with low serum vitamin B12 level.
    Journal of Nutrition and Health 06/2013; 46(3):239. DOI:10.4163/jnh.2013.46.3.239
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