Macrocytic Anemias

Question 1

megaloblastic anemia: cause

Answer 1

folate and cobalamin def

Question 2

megaloblastic

Answer 2

large immature RBCs which often have Howell Jolly bodies

Question 3

anisocytosis

Answer 3

varied RBC size

Question 4

poikilocytosis

Answer 4

varied RBC shape

Question 5

microcytosis

Answer 5

decrease in RBC size

Question 6

hypochromasia

Answer 6

pale RBCs

Question 7

reticulocytosis

Answer 7

increased RBC production

Question 8

reticulocytopenia

Answer 8

decreased RBC production

Question 9

macrocytic MCV

Answer 9

> 100 fl

Question 10

increased RBC turnover in macrocytic anemias may cause elevated:

Answer 10

plasma LDH and iron.

plasma bilirubin –> icterus/jaundice

Question 11

Howell Jolly bodies: cause

Answer 11

disorder of DNA synthesis in the bone marrow

Question 12

B12 def anemia: size & shape

Answer 12

will be variation in size (anisocytosis) and shape (poikilocytosis) of RBCs

Question 13

B12 def anemia: blood sample

Answer 13

may have Howell-Jolly bodies, cabot rings or nucleated RBCs. abnormal WBCs like hypersegmented neutrophils (PMN) cells

Question 14

B12 biochemical status

Answer 14

plasma or serum vit B12 deficient = 150-200 pg/mL

Question 15

B12 def: s/s

Answer 15

weak, tired, yellow icterus, paresthesia, hyperreflexia/decreased reflexes, ataxia, stocking and glove sensoty loss, incontinence, neuropathy and Lhermitte’s sign

Question 16

pernicious anemia (PA): cause

Answer 16

syndrome of cobalamin def caused by gastric mucosal defect that diminishes IF synthesis in parietal cells

Question 17

PA: risk factors

Answer 17

rare in ppl <40.

common in northern European origin, runs in families, linked to helicobacter pylori infection and autoimmune diseases

Question 18

B12 def: autoimmune risk factors

Answer 18

antibodies to parietal cells are present in 90% of cases. lack of IF causes malabsorption of B12

Question 19

B12 def: congenital defects risk factor

Answer 19

congenital PA (no/defective IF production). ismerlund-Grasbeck syndrome - defects of cubilin, the ileal receptors for IF

Question 20

B12 def: transcobalamin II defects risk factor

Answer 20

can’t transport B12 into cells. cause probs similar to PA, failure to thrive, mental retardation. all these defects respond to high dose parenteral B12 therapy

Question 21

B12 def: gastric probs risk factor

Answer 21

low IF production. gastrectomy, bypass, zollinger, severe gastritis

Question 22

B12 def: ileal probs risk factor

Answer 22

poor absorption d/t damage/removal of terminal ileum. ileal resection, ileitis, Crohn’s in ileum, GSE, AIDS or scleroderma

Question 23

B12 def: competitive parasites risk factor

Answer 23

fish tape worm, bacteria in intestine may compete for cobalamin

Question 24

B12 def: pancreatic enzyme related risk factor

Answer 24

pancreatic proteases are needed to release cobalamin from R proteins. pancreatitis, pancreatectomy

Question 25

B12 def: high B12 requirement risk factor

Answer 25

pg, high RBC production as in chronic hemolytic anemias, some cancers, hyperthyroidism, nitric oxide anesthesia. Elderly have difficulty freeing B12 from food due to low stomach acid, sups are wll absorbed.

Question 26

meds that impact B12 status/absorption

Answer 26

nitrous oxide, cholestyramine, clofibrate, paraaminosalicylic acid, INH, neomycin, netformin, phenformin, colchicine, H2 receptor blockers, PPIs (Prilosec, prevacid, nexium), anticonvulsants (phenobarbital, Dilantin)

Question 27

cobalamin def: mgmt

Answer 27

B12 injection, or absorbed via passive diffusion in terminal ileum.

Question 28

folate & B12 def elevation of:

Answer 28

serum iron, liver enzymes, bilirubin

Question 29

folic acid biochemical value

Answer 29

def = <3 ng/mL

Question 30

folic acid def : s/s

Answer 30

weakness, tiredness, glossitis, red tongue

Question 31

folate def: dietary

Answer 31

poor folate intake has improved w/fortification. some foods contain conjugase inhibitors which prevent folate digestion and lowers bioavailability but effect is minor.

Question 32

folate def: risk factors

Answer 32

alcohol, malabsorption syndroms (GSE, intestinal resection, enterisits, Crohn's)

Question 33

folate def: higher needs in

Answer 33

pg, hyperthyroidism, increased hematopoiesis, liver cirrhosis

Question 34

folate & methotrexate

Answer 34

structurally similar to folate. do not take folate w/med taken for chemo. for other disorders, folate is fine

Question 35

folate & Dilantin

Answer 35

folate status may decline w/Dilantin. folate may decrease med's anticonvulsant effect, so take min amt of folate needed if deficient

Question 36

folic acid & other meds

Answer 36

antacids, anticonvulsants, aspirin, barituates, bile acid sequestrants, Colestipol, cycloserine, diuretics, famotidine, lithium, isoniazid, metformin, triamterene

Question 37

folate def mgmt typical dose

Answer 37

250 - 1,000 mcg/day

Question 38

severe folate def mgmt dose

Answer 38

such as in megaloblastic anemia and malabsorption disorders: 1-5 mg (1,000-5,000 mcg)/day