Microcytic Anemia Flashcards
(27 cards)
What is microcytic anemia?
Deficiency in oxygen carrying erythrocytes Microcytic & hypochromic → small erythrocytes w/insufficient Hb (hence pale)
What is a common cause of microcytic anemia?
iron deficiency
Who is at risk for microcytic anemia?
→ increased Fe requirements (e.g. pregnancy) → Fe malabsorption → Blood loss *consider those on PPIs have decreased stomach acid (stomach acid increases Fe bioavailability)
Expected lab values w/microcytic anemia
Mean Cell Volume (MCV): <80fL
Mean Cell Hemoglobin Concentration (MCHC): <30%
Serum Iron (SI): <30 mcg/dL
Transferrin saturation: <10%
Serum ferritin: <20 mcg/L
Where does iron absorption take place?
intestine, primarily in duodenum
Dietary sources of iron
organ meats, brewer’s yeast, wheat germ, egg yolks, oysters, green leafy veggies
Difference between heme and non heme iron absorption
→ Heme Fe in meat well absorbed → non-heme Fe 1st reduced by ferrireductase to ferrous Fe before absorption
How is iron transported?
Transferrin: beta globulin that binds 2 molecules of ferric Fe→ transports Fe in plasma to maturing erythroid cells in bone marrow
How is iron stored?
Fe primarily stored as ferritin in intestinal mucosal cells, macrophages in liver, spleen, and bone, parenchymal liver cells
Significance of serum ferritin
estimate of total body Fe stores
How is iron eliminated?
• No mech for Fe excretion → small loss in feces, trace in bile, urine, sweat • why hepcidin is imp – main Fe hormone, decreases absorption
How much iron is lost/excreted daily?
• ~1mg iron lost daily • 10% women lose >2mg/day on menses
Types of PO iron
Ferrous sulfate (Feosol) Ferrous gluconate (Fergon) Ferrous fumarate (Feostat)
PO iron: adverse reactions
Nausea, epigastric discomfort, abdominal cramps, constipation, diarrhea, black stools GI upset: Fumarate causes most
Which type of PO iron is preferred?
Ferrous sulfate
What is the benefit of slow release PO iron?
marketed as less GI upset, but releases in ileum, late for absorption. NOT preferred.
When is iron best absorbed?
on empty stomach but may take w/food to minimize GI effects
How long should iron supplementation continue in IDA?
3-6mths after correcting IDA cause
What happens in acute iron toxicity?
causes GI tract corrosion & direct cellular damage
Who is most at risk for acute iron toxicity?
Almost exclusively occurs in young kids so store out of reach!
How is acute iron toxicity treated?
whole bowel irrigation and iron-chelating agents (e.g., IV deferoxamine)
Types of IV Iron
Iron dextran (INFeD)
Sodium ferric gluconate (Ferrlecit)
Iron sucrose (Venofer)
What are the indications for the different types of IV iron?
INFeD: IDA
Ferrlecit & Venofer: CKD pts on hemodialysis
Side effects of INFed?
HA, lightheadedness, fever, arthralgias, anaphylaxis/death
