Function Of Vitamin B12 :Important for metabolism.Formation of red blood cells .Maintenance of the central nervous system..
Folate Vs B12 Etiology Arrest of Erythrocyte Mutation Arrest of Methonoin Formation Within Months Within Years Onset Symptoms of Anemia Symptoms of AnemiaPresentation Never Neurological Neurological Symptoms Are Common Lab Folate decrease B12 decreaseHomocysteine Decrease IncreaseMethylmalonic Acid WNL Increase
FactFolic Acid Supplement Can Mask Vitamin B12 Deﬁciency
Fact Decreased absorption/Interactions!Aminosalicylic acid can reduce oral vitamin B12 absorption,Excessive alcohol intakeReduced vitamin B12 levels may be more common with PPIs than with H2-blockersFolic acid particularly in large dosesAnticonvulsants Phenytoin, phenobarbitalNitrous oxideNicotineNeomycinMetformin (Glucophage)Hormonal contraception
Most likely Populations to Get B12 DeﬁciencyBasics Hx P/E Dx Tx
Fact Ask about Drugs !Oral contraceptive users generally have lowerserum vitamin B12 levels than nonusers
Fact Ask about Diet !Nursing infants of mothers who adhere to astrict vegetarian or vegan diet throughout theirpregnancy and while breastfeeding might alsoexperience serious B12- related deficiencyeffects ,Even when the mother is not anemic orsymptomatic in any way.
Basics During a checkup for HTN, a 65-year-old Hx female reports a 2-month history of tiredness, feeling faint from “getting up too fast”, and “memory problems”. P/E Dx Tx
FactAll patients newly diagnosed with unexplainedcognitive decline or dementia should beassessed for a possible vitamin B12 deficiency
What may lead to depletion and deﬁciency?Basics Hx P/E Dx Tx
FactPernicious anemia is an autoimmune disease inwhich antibodies attack gastric cells, resulting inimpaired production of intrinsic factor that is critical forabsorption of vitamin B12.
FactPernicious anemia, is the most common causeof B12 deficiency WorldWide , but In the US,most cases of vitamin B12 deficiency are due tomalabsorption.
Fact During Surgery !Nitrous oxide causes the inactivation of vitaminB12, which might result in acute hematologic orneurologic complications of vitamin B12 deficiency.Because nitrous oxide is a commonly usedanesthetic in surgery, people at risk (e.g., theelderly) should be monitored for a developingsymptomatic vitamin B12 deficiency.
Who should be Tested For B12 deﬁciency?Basics Hx P/E Dx Tx
Order:Basics Complete blood count (CBC) Peripheral blood smear Serum cobalamin (B12) Hx Not all patients with a vitamin B12 deficiency will have hematologic P/E manifestations. Dx a low serum B12 level does not automatically mean a deficiency. Tx
Fact Falsely low values !have been associated with :Multiple myelomaOral contraceptivesFolate deficiencyPregnancy
Fact Falsely Normal values !have been associated with :Liver diseaseMyeloproliferative disorders Polycythemia veraRenal insufficiency Essential thrombocytosis Myeloﬁbrosis Chronic myelogenous leukemia (CML) So it is important to evaluate further.
Basics So What To do ? Hx Complete blood count (CBC) Peripheral blood smear Serum cobalamin (B12) P/E Dx Are Not Specific , Nor Accurate Tx
Confirmatory Testing By far, the most common, accurate, and widely used confirmatory tests for identifying vitamin B12 deficiency are tests for...... Homocysteine (Hcy) Methylmalonic Acid (MMA) is a sensitive indicator for a vitamin B12 deficiencylow levels of vitamin B12 increases in total serum Hcy. Shilling Test Differentiate b/w Nutritional B12 def. vs IF Not Used Anymore !