Vitamin B12 deficiency
Alerts and Notices
Synopsis
Vitamin B12, or cobalamin, is a water-soluble vitamin found in meat, fish, and dairy products and, once combined with intrinsic factor in the stomach, is absorbed in the ileum. Patients at risk for vitamin B12 deficiency include those with a lack of intrinsic factor (pernicious anemia) or antibodies to intrinsic factor, malabsorption syndromes (especially those who have had a gastrectomy, gastric bypass, or chronic pancreatitis), or infections such as Helicobacter pylori or tapeworm infections. In addition, strict vegans, older adults, and people with alcohol use disorder are particularly vulnerable to vitamin B12 deficiency. Elderly patients are at risk due to the high prevalence of atrophic gastritis. Patients with autoimmune conditions such as Graves disease, thyroiditis, and vitiligo are also at risk.
Codes
ICD10CM:E53.8 – Deficiency of other specified B group vitamins
SNOMEDCT:
190634004 – Cobalamin deficiency
Look For
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Folate deficiency or deficiency of other vitamins – Differentiate between folate deficiency and vitamin B12 deficiency with methylmalonic acid and plasma total homocysteine assays.
- Other causes of macrocytic anemias, including aplastic anemia or myelodysplastic syndrome
Best Tests
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Management Pearls
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.Subscription Required
References
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Last Reviewed:01/30/2019
Last Updated:01/30/2019
Last Updated:01/30/2019
Vitamin B12 deficiency