Iron Flashcards
Most found in ____ in circulating RBC
Remainder in
best dietary sources
Nonheme iron sources
nonheme iron is enhanced when consumed w foods containing
hemoglobin
mobilizable iron stores and myoglobin
heme iron in meats (meat, poultry, fish)
veggies, fruits, fortified bread/cereal
VC or meat
Major role of iron
Lack of iron leads to
Men need
Women need
carry O2 in hemoglobin
Hb synthesis impaired, leading to anemia and dec O2 delivery to tissue
1 mg/day
1.4mg/day (more in preg/childhood/adolescence)
Absorption occurs in
complex binds
there
Some Fe remains
SI- enterocytes secrete transferrin into lumen to bind 2 Fe
receptors on apical membrane and taken to cytoplasm
Fe is released and binds ferritin (stores iron inside enterocyte)
bound to transferrin, IC transported to plasma to different transferrin
Iron-transferrin complex circ in plasma until
Fe entering cells may be incorporated into
Storage of iron occurs in
In absence of bleeding
reaches transferrin receptors on surface of erythroid cells
functional compounds, ferritin, regulate future Fe metabolism
liver, spleen, BM
minimal iron is lost daily
Binding of iron to transferrin and ferritin limit
At end of lifespan, RBC undergoes
Fe is then
additional iron required for red cell synth
Fe circ in ferric state, limiting damage from free rads/lipid peroxidation
phagocytosis by reticuloendothelial system
recycled to form new RBC
comes from diet
Acute blood loss anemia, rate of RBC production
if delivery to BM is dec
results in
No _____ excretory pathway
Fe is lost via
Iron enters via
limited by mobilization of iron
marrow’s proliferative response dec, Hb synth impaired
microcytic, hypochromic anemia
regulatory
blood loss, loss of epithelial cells from skin/gut/GU
Food/supps, RBC transfusions/injection
Fe def anemia due to
CM
include
Pica
when prolonged or severe
blood loss, inadequate intake/malabsoprtion
depend on degree
fatigue, reduced work capacity, SOB, pallor
chew on nonnutritive substances (clay/ice)
concave nailbeds (koilonychia), fissures at mouth angles, thin membrane web in esophagus/dysphagia (Plummer Vinson syndrome)
Heme iron is _____ absorbed
infants and children more likely to be
during last 2 trimesters
most readily
Fe deficient due to demand of body growth/low dietary intake
requirement inc, iron supps recommended
Cow’s milk is poor in ___
early ingestion results in
infants should receive
preterm infants also need
Fe (not recommended for less than 1yr)
Fe def anemia
Fe fortified formula
Fe supplementation
Earliest change in Fe def shows
Lab abnormalities process
further worsening
blood smear indicaes
absent iron stores in BM
MCV falls, dec HCT/Hb
Serum ferritin/Fe falls, TIBC rises, dec transferrin sat
Pt becomes hypochromic, microcytic anemic, dec RBC hb conc
microcytic red cells w inc cental pallor
Serum iron
TIBC
transferrin sat
Serum ferritin
Serum transferrin receptor
BM iron
Liver Fe
Def vs Overload
Dec, great inc
inc, normal
great dec, great inc
dec, great inc
inc, normal
none/low, morma,
none/low, great inc
Toxicity chance is
High dose supps can lead to
Pt susceptible to excess iron intake problems include
low
GI sx- cons/diarrhea, NV
Hereditary hemochromatosis, chronic alcoholism, alcoholic cirrhosis, LD
Fe toxicity is a concern in
Manifests as
w severe overdose __ admin
this agent
eventually
child w unintenional ingestion
GI sx, then shock, met acid, hepatotoxicity, bowel obstruction
deferoxamine
chelates ferric Fe in blood, forming water soluble ferrioxamine
excreted via kidneys
