Macrocytic anemia Flashcards
Cobalamin deficiency
12% of people and seen with anemia, macrycytosis and leukopenia and thrombocytopenia. On peripheral smear can see hypersegmented polymorphonuclear leukocytes and elevated LDH.
normal B12 level
>300 pg/ml and unlikely deficient but may have a 1-5% risk of being deficient
200-300 pg/ml of B12 is
borderline result. cobalamin (b12) deficiency
possible check serum MMA (methylmalonic acid level)
<200 pg/ml of B12
consistent with cobalamin deficiency (specificity 95-100%)
even if serum B12 is low what do you need to do?
need to get MMA and homocysteine level because serum B12 are notoriously unreliable given significant fluctuations in a patient on a given day
<200 are consistent with deficiency
>300 are generally replete
between 200-300 can be low
what causes low B12 levels:
bariatric surgery vegan diet metformin use Crohn’s dx pancreatic insufficiency PPI and H2 blocker use
Replacement of B12
1000-2000 mcg day
what is seen on peripheral smear?
see hyper segmented neutrophils
folate deficiency is caused by:
ETOH folic acid antagonist (methotrexate, trimethoprime, pyrimethamine) OCP celiac sprue dilantin (phenytoin) relative folate deficiency - from sickle cell chronic hemolysis or hereditary spherocytosis) pregnant
folic acid deficiency is not associated with
neurodeficits - that’s vitamin B12
high methylmalonate and high homocysteine levels is
B12 or cobalamin deficiency
normal MMA and high homocysteine levels
folate deficiency
vitamin B6/pyridoxine deficiency (can have this but will have normal MCV)
Differential for macrocytic anemia
what has high MMA and high homocysteine levels
B12 deficiency
B6 and folate will show low MMA and high homocysteine levels.
What can cause this?
hypersegmented neutrophil - megaloblastic anemia. normally should only see 5 lobes.
folate, B12 deficiency, and ETOH abuse
