Iron deficiency Flashcards
Inorganic iron salts exists in 2 forms
– Ferrous (2+) “reduced” : gained an electron
– Ferric (3+) “oxidized” : lost an electron
is an essential element in humans, being the central ion in heme (the non-protein component of hemoglobin, myoglobin, and cytochromes)
iron
Iron deficiency causes a failure
in heme synthesis
Iron deficiency results in the production of red cells that are
smaller than normal (microcytic) and paler than normal (hypochromic)
an essential component of hemoglobin, and is responsible for binding oxygen in a pocket between the globin chain and the porphyrin plate.
Iron in the ferrous form
iron deficiency leads to
anemia and tissue hypoxia
what is highly toxic to the cells and must be bound to protein at all time
Free iron
what is Haber-Weiss reaction
Fe+2 + H2O2 Fe+3 + OH- + OH
Free-radicals can attack:
– Cellular membranes - DNA – Proteins
Iron excess possibly related to
cancers and cardiac toxicity
about (_) of iron is lost from the body per day
1 mg
how is iron usually lost
through sloughed mucosal epithelial cells or blood loss
The majority of iron required by the body is acquired by
recycling iron from senescent red cells.
2 ml of blood contains approximately (_) of iron.
1 mg
Daily red cell production requires
20 - 25 mg Fe2+
only (_) of iron is absorbed each day from the diet
1 - 1.5 mg
Adult human body contains about
3000-4000 mg of iron
Most of the iron within the body is found in
hemoglobin within erythrocytes (about 1800 mg of iron)
Iron is also stored in macrophages and in hepatocytes, which represents the storage pool of iron
about 1600 mg of iron
Storage iron occurs in two forms
– Ferritin (soluble)
– Hemosiderin (insoluble)
Excess iron can be complexed to phosphate and
hydroxide to form
hemosiderin
Abnormal quantities of hemosiderin can occur
after internal hemorrhage (bruising)
Hemosiderin can also accumulate inside cells that normally
metabolize red blood cells, if there is increased red blood cell breakdown
accumulations of hemosiderin occur in the liver
in some kinds of anemia or after large numbers of blood transfusions
a glycoprotein synthesized in the liver having a central role in the body’s metabolism of iron
Transferrin
Each mole of transferrin can transport
2 moles of Fe3+
how does the iron dissociate from transferrin
The acidic pH of the lysosome
Dietary iron is obtained from
from inorganic (non- heme Fe 3+) or animal sources via (heme Fe 2+)
Plasma transfer of iron from enterocytes to the transport protein, () , occurs through specific iron channels, called () and is facilitated by a protein called (_)
apotransferrin
ferroportins
hephaestin
When apotransferrin binds iron, it is called
transferrin
a main iron regulating protein decreases ferroportin and thus decreases iron absorption
Hepcidin
Iron absorption mainly takes place in
proximal small intestine
half clearance time of transferring bound iron is
60-90 minutes
Iron absorbed from the intestine is stored as () in () epithelium or transported in plasma as (_)
ferritin
intestinal
transferrin
Erythroid progenitors obtain iron for hemoglobin synthesis from
1-plasma transferrin
2- from recycling of senescent erythrocytes by macrophages in bone marrow, spleen and liver.
Excess Iron also stored in macrophages as
ferritin
Globins are broken down to
amino acids
porphyrin ring which is converted
to bilirubin
In macrophages, (_) is a ferroxidase and facilitates the transfer of macrophage iron to transferrin
ceruloplasmin
(_) downregulates ferroportin causing iron sequestration in macrophages.
hepcidin
Whole body iron levels are regulated primarily at the level of absorption
by enterocytes
active excretion of iron occurs by
bleeding or sloughing of iron- laden enterocytes
Regulation of iron uptake by enterocytes and release of iron stores from macrophages and hepatocytes is mediated by the hormone
hepcidin
where is hepcidin produced
liver
decreases serum iron by decreasing iron absorption and preventing macrophages from releasing iron
hepcidin
Hepcidin is regulated by
iron levels and erythropoiesis
Hepcidin is also increased by inflammatory cytokines particularly
IL-6, and reduces available iron during inflammatory processes
what increases iron absorption
Citrate and ascorbate
what decreases iron absorption
Tannates
Duodenal microvilli contain (_) to promote absorption of ferrous iron
ferric reductase
what is a decrease in the total amount of red blood cells (RBCs) or hemoglobin in the blood, or a lowered ability of the blood to carry oxygen
Anemia
Types of Anemia based on Clinical Picture
*Iron deficiency Anemia
*Megaloblastic Anemia
*Pernicious anemia
*Aplastic Anemia
*Hemolytic Anemia
-Thalassemia anemia
-Sickle cell Anemia
Laboratory testing for For Iron Defeciency Anemia
- Serumiron
- Totalironbindingcapacity(TIBC)
- Serumferritin
- Completebloodcount(CBC)
- Bonemarrowbiopsy
- Liverbiopsy
Ferritin may be increased in serum by:
– Tissue release (hepatitis, leukaemia, lymphoma)
– Acute phase response (tissue damage, infection, cancer)
Causes of Iron Deficiency Anemia
*Increased iron utilization
– Postnatal growth spurt
– Adolescent growth spurt
* Physiologic iron loss
– Menstruation
– Pregnancy
* Pathologic iron loss
– GI bleeding
– Genitourinary (GU) bleeding
* Decreased iron intake
– Meat poor diet
– Malabsorption
General anemia’s symptoms
– Fatigue
– Dizziness
– Headache
– Irritability
– Palpitation
– Dry, pale skin
– Hair loss
– Brittle nails
