10.10.18 Iron Deficiency Flashcards
How is heme iron absorbed?
How is non-heme iron absorbed?
Heme- meat
Nonheme- stomach acid and other substances that impede/absorb iron
Dietary iron is reduced to ferrous state by this enzyme
DcytB- ferric reductase
Ferrous iron is then transported into the enterocyte by this transporter
DMT1
Iron leaves the enterocyte and enters circulation by this protein facilitated by haphaestin
Ferroportin
Where else does ferroportin release iron from other than the enterocyte?
Hepatocyte and macrophages
What blocks the action of ferroportin and lowers serum iron concentration
Hepcidin
binds to iron in the bloodstream and transports it to cells
Transferrin
This goes up when the body is iron deficient
This level falls as body becomes iron deficient
TIBC
Ferritin
fraction of available iron binding sites which have iron bound to them. This falls as body becomes iron deficient.
Transferrin saturation
How does iron leave the body?
When cells are lost
- Menstruation
- Pregnancy
- Blood donation
- GI blood loss
- GU loss
What are good sources of iron
Liver, Oysters, Clams
What is iron deficiency in adults almost always due to?
What are other components that can contribute to iron deficiency?
Blood loss
Malabsorption or dietary insufficiency
What will the body in early iron deficiency use before dropping the hemoglobin
As iron deficiency becomes more profound what will occur?
Iron stores
Anemia
What are the main clinical presentation of iron deficiency?
- Pica
2. Thrombocytosis- elevated platelet count
Spooning of the nails
Koilonychia
Obsessive consumption of substances with no nutritional value, such as ice, starch, dirt, or paper
Pica
What are the lab values that show iron deficiency?
- Elevated RDW
- Falling MCV
- Serum Iron falls
- TIBC increases
- Transferrin saturation falls
- Ferritin low
What is the single best best test for iron deficiency and what is the gold standard for evaluation?
Test- Ferritin
Gold standard- bone marrow evaluation
What is blood like during the last trimester?
What happens after birth (physiologic anemia of infancy)
RBC mass and production increases, iron stores laid down, Hb high
Hb and reticulocyte drops; preemies have lower Hb nadir than term infants
What happens to blood during puberty
Rises more for males than females
Males need more myoglobin for muscle and women begin menstruation
What are risk factors for iron deficiency in children?
Perinatal risk factors (maternal iron levels) and dietary risk factor (cows milk)
How do you prevent iron deficiency in children?
- Treat iron deficiency and pregnant and lactating women
- Use iron-fortified formulas
- Avoid cow’s milk until 1 year
- Children 1 to 5 should consume no more than 600 mL of milk per day
What are the consequences of iron deficiency in children?
- Neuropsychiatric manifestations
- Increased risk of thrombosis in infants
- Increased risk of lead toxicity
What are global health strategies for iron deficiency?
- Iron supplementation
- Fortification
- Antihelminthic therapy (deworming)
What are the global health downsides to iron supplementation?
- Can increase susceptibility to malaria (parasite can’t infect iron deficient cells)
- Iron overload in areas of severe thalassemias that increase iron absorption
In this type of anemia, cytokines act to sequester iron away from the bloodstream by increasing levels of hepcidin thus allowing serum iron levels and TIBC to fall
Anemia of Chronic Disease
