Nutritional Anemia Flashcards
What are the disorders you think of for DDX of Macrocytic Anemia?
Vit B12 Deficiency
Folate Deficiency
Myelodysplastic disorders
What causes the cells, on a structural level, to become macrocytic?
-lack of either vitamin B12 or folate slows the synthesis of DNA but not RNA, so the RBC increases in size before dividing resulting in macrocytic RBC
Where do we get our Vitamin B12 from?
-meat and dairy products only!
How does a person develop a Vit. B deficiency macrocytic anemia?
-Vitamin B is unable to be absorbed or you have severe inadequate intake of dietary B12 for several years.
Dietary intake» R factor»> Intrinsic Factor»> IF-CBL»> ileum»>absorption
What is pernicious anemia?
- autoimmune attack on gastric Intrinsic Factor
- -anti-IF abys block the attachment of Cbl to IF
- -attachment of Cbl-IF to ileal receptors are blocked.
What is chronic atrophic gastritis?
leads to the decline of IF production, associated w/ autoantibodies against gastric parietal cells, results in less acidic pH in stomach.
Etiologies of B12 Deficiency
- pernicious anemia*
- Chronic Atrophic Gastritis*
- chronic alcoholism*
- gastrectomy*
- HIV infection
- crohns
- inadequate dietary intake (vegans, pregnancy)
Clinical presentation of Vit B12 Anemia
- macrocytic, MCV>100, elevated iron levels, indirect bilirubin & LDH (indicating increased RBC breakdown)
- peripheral smear: megaloblastic, hypersegmented neutrophils, & macrocytosis
- thrombocytopenia and neutropenia–bone marrow gets suppress over all leading to decreased cells.
-homocysteine levels increased (both folate and vit B12 required to convert homocysteine to methionine); build up leads to venous thromboembolism and
atherosclerosis
- neurologic changes; d/t defect in myelin formation, peripheral neuropathy (burn, numb, tingle, sting), weakness, spasticity, memory loss, irritability, and dementia
- increased risk of osteoporosis (d/t suppression of osteoblast activity)
Folate Deficiency Etiologies
- poor nutrition (folate found in meat, green leafy veggies, nuts, fruit)
- alcoholism
- infants fed primarily fed goats milk
- drugs interfering w/ folate metabolism– trimethoprim, methotrexate, phenytoin
Folate Deficiency Presentation
- macrocytic anemia
- hyperhomocysteinemia
- NO neurologic findings
After how much time may folate deficiency occur? B12?
- 4-5 months
- YEARS!!!
If pt has borderline abnormal vitamin values (B12 and folate) what do you test next?
-metabolites! methymalonic acid and homocysteine
–if BOTH are ELEVATED then B12 deficiency
–if MMA is normal and homocysteine is increased FOLATE deficiency.
What test used to be used to test pernicious anemia?
-schilling test
Treatment of Folate Deficiency ?
What is something to look for in particular?
-folic acid po daily for 1-4mo or until complete hematologic recovery
** if they have B12 deficiency!
always rule out B12 deficiency before administering folic acid because folic acid can partially reverse some of the hematologic effects of B12 deficiency. If you only treat for folic acid and they have B12 deficiency as well their neurologic sx will progress and become permanent after 6mo
-if urgent draw blood prior to tx to test B12 deficiency and then treat BOTH folic acid and B12 until tests are known.
Treatment of B12 Deficiency
-IM or deep SQ injections of Cobalamine –1000mcg every day for 1 week, 1mg every week for 4 weeks, if underlying disorder persisits» 1mg/mo.
–other preparations: oral Cbl, sublingual, and nasal spray
