3.19 NIELL Nutritional Anemias Flashcards
Most important cause of a microcytic hypochromic anaeaeaemia
Iron Deficiency
3 Transporter Proteins of Iron
transferrin, transferrin receptor and ferritin
Where is Iron Absorbed from the Diet in GI tract?
Proximal duodenum
Iron Stores in Macrophages
Ferritin and hemosiderin
How is Iron excreted from the body???
ITS NOT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Easiest store of Iron to mobilize?
Ferritin, it is water soluble compared to hemosiderin which is not.
How much Iron is in 1ml of blood
1mg of Iron
Labile Iron Pool
Iron leaving the plasma and entering the interstitual and intracellular fluid compartments 80-90mg
Transferrin
- Smallest pool, but most active
- Carrying protein in the plasma
- Turns over 10xday
- Found in plasma and is 1/3 saturated with Fe
- Apotransferrin is syn in liver
Who are at risk for Iron Deficiencies?
Pregnant Women>young nonpreg women>infants
Least: MEN (cheers!!) and postmenopausal women
What is best dietary source of iron?
Liver
What acts as the “doorway” for Fe to enter circulation
Ferroportin
-Negatively regulated by HEPCIDIN
What facilitates transfer of Fe from a mother to her fetus??
Ferroportin again
Ferriportin
Cellular exporter of Fe into plasma
Regulates: (1) transfer of iron from mother to fetus (2) iron absorption in intestines (3) Iron export from macrophages
Regulation of Iron Uptake
Hepcidin
- Neg Reg
- Binds Iron exporter, ferriportin and degrades
- -inhibits iron flow into plasma from recycled senscent RBC
- -Inhibits duodenal enterocytes engaged in absorption of dietary iron
- -Inhibits hepatocyes that store Iron
Factors Effecting Absorption of Non-Heme Iron
Increase: Reducing agents (ascorbic, gastic acid)
Decrease: (1) insoluble complexes (phytates, grains, phosphates, egg yolks) (2) Chelating agents (turkish clay)
(3) Inhibit or compete for absorption (tannic acid, tea, Ca)
Factors outside GI tract increasing Iron Absorption
Hypoxia (decreases Hepcidin) Anemia (also decreases Hepcidin) Depletion of Iron Stores Increased erythropoesis --Anything that happens when Fe is low (other than ACD) or is trying to stimulate RBC production
Cause of Fe Mal-absorption
GI Surgery (weird one for peptic ulcers that should never be done)
Non-Tropical Sprue: gluten allergy (immuno rxn in enterocyte) stop all grains, happens tille late childhood then goes away till 60s
Tropical Sprue: overgrowth of coliforms in jejunum: decreases folic acid
Picca: eating laundry starch and clay in stupid places that eat clay
Causes of GI Bleeds
Peptic ulcer disease, Hiatal Hernia, Chronic Gastritis, Hemorrhoids, Intermitant bleeding after GI surgery, Neoplasms of the GI tract
GI Bleeds in Infants
Milk allergy: boil and there is no Rxn
Meckel’s Diverticulum: make HCL in intestines that leads to bleeding
Unusual Cause of Fe Deficiency
Resp Tract Bleeding (lung cancer)
- Intravascular hemolysis (autoimmune)
- Chronic Renal Dialysis
- Blood donations too often
- Factitious Bleeding (nurses taking there own blood and lying about it?)
What did the 100 y.o. Korean Girl have and the other kid?
Hookworm common cause of anemia in underdeveloped countries
- Worm migrates to lung up trachea and down esophagus settling into small intestine
- Starvation is a very common cause also in underdeveloped countries
Clinical Manifestations of Iron Deficiency
Symptoms
-Asymptomatic early
-Fatigue, headaches and parathesias (burning feeling), Irritability, Decrease exercise tolerance, burning tongue, Picca (eating disorder)
Physical Findings:
Pallor
Glossitis, Stomatitis, Angular Chelitis (all means Red tongue with cracks around the mouth)
Rare: koilonychia: concave nails from chronic aneaeaemia
CBC with Iron Deficiency
WBC: unaffected Hct: low MCV: low (b/c RBC are small) RDW: high because variable widths Platelets: sometimes elevated Retic Count: extremely low (not making new RBC)
