0521779407-07 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:10
Folic Acid/Cobalamin (Vitamin B12) Deficiency 579normal stage I test because they can absorb crystalline [57Co] cobal-
amin normally.management
■If patient decompensating from congestive heart failure, give 1
unit of packed cells slowly plus dual vitamin replacement (1 mg
cobalamin and 1 mg folic acid) stat. Also for suspected cobalamin-
deficient neurologic disease, give cobalamin and folic acid immedi-
ately after drawing blood tests.
■With less urgent clinical picture, await confirmatory diagnostic tests
before initiating therapy.specific therapy
The recommended daily allowance (RDA) of vitamin B12 (cobalamin)
for men and nonpregnant women is 2.4 mcg; pregnant women, 2.6
mcg; lactating women, 2.8 mcg; and children 9–18 years,∼1.5–2 mcg.
The RDA of folate for adult men and nonpregnant women is 400 mcg;
pregnant women, 600 mcg; lactating women, 500 mcg; children 9 to 18
years, 300–400 mcg.
■For PA-related cobalamin deficiency: Intramuscular cobalamin 1 mg
daily×1 week, then 1 mg biweekly for 4 weeks, then monthly injec-
tions for life
■Alternatively, oral cobalamin 2 mg orally for life (1% passively
absorbed sufficient for daily replacement) after acute replenishment
of depleted cobalamin stores using IM regimen above
■Folate deficiency: Oral folic acid 1 mg PO daily, all cases
Modified Therapeutic Trials.
Indication: When clinical suspicion is against folate/cobalamin
deficiency but other clinical, morphologic, and/or biochemical
abnormalities are inconclusive (e.g., megaloblastic bone marrow that
could be secondary to chemotherapy, myelodysplastic syndromes, or
acute myeloid leukemia; or in pregnancy, AIDS, or alcoholism, when
anemia is likely to be multifactorial). Documenting failure to respond
to combination of folic acid 1 mg orally×10 days and cobalamin 1
mg IM daily×10 days rules out folate/cobalamin deficiency. After all
such negative trials, a bone marrow evaluation is indicated to identify
another primary hematologic disease.follow-up
■Note: Folic acid alone cures megaloblastosis of folate/cobalamin
deficiency but aggravates neuropathology of cobalamin deficiency.