Tuesday, April 12, 2011

Iron and Iron defeciency anemia - quick recap

Eventhough we have read about Iron deficiency and anemia for a while now, we kind of need some reinforcements from time to time.(I....definitely need some!!). 
Lets start with the iron  panel (well ...never forget to examine and correlate with the pt history & findings!)


IRON PANEL - A normal adult body contains 3-4 grams of iron; about 2 grams is stored in hemoglobin, about 400mg in iron-containing proteins, about 3-7 mg is bound to transferrin in plasma, and the remaining iron is stored as ferritin and hemosiderin (an iron storage complex found within cells). Transferrin saturation(TSAT) & total iron binding capacity(TIBC) are 2 common tests done. TSAT essentially measures the same thing as TIBC. Total iron binding capacity indicates how much room there is for iron, while TSAT shows how much iron is currently saturating transferrin. Usually transferrin is about 1/3 full of iron: serum iron (Fe) divided by TIBC = 1/3. TSAT is reduced in patients with IDA and often in patients with anemia of chronic disease.

Ferritin is the cellular storage protein for iron in tissues found in the intestines, liver and spleen which contain approximately 20% iron.In general, TSAT < 20 &/or ferrtin<200ng/dl are considered to be iron deficient.


CALCULATE IRON DEFICIT - (especially if rapid replenishment is planned) - First, calculate the patient’s hemoglobin deficit by subtracting their current hemoglobin from the goal of 14g/dL. Second,calculate the body’s total hemoglobin deficit in grams by multiplying pts. weight by the normal blood volume of 65mL/kg.Tis gives the total hemoglobin deficit.There are 3.3mg of iron for each gram of hemoglobin in the blood. So,lastly, multiply the total hemoglobin deficit by 3.3mg to calculate iron deficit. 


SOME FACTS ABOUT ORAL IRON REPLACEMENT

*The recommended daily dose for the treatment of IDA in adults is 150-200 mg per day of elemental iron.(a 325mg FeSo4 tablet has 65mg iron, a 325mg ferrous fumarate has 106mg of iron)
*It is best to give iron on an empty stomach ...as otherwise the iron binds with food in the stomach and impair
absorption; additionally, iron is best absorbed in an acidic environment.
*Since Iron is absorbed in the duodenum, enteric coated tablets may not be useful.
*After initiating oral iron, reticulocytosis will peak at 7-10 days in patients with moderate to severe anemia. *Hemoglobin levels begin to rise in 2 weeks. If taken in adequate doses, the hemoglobin would normalise by 8 - 10 weeks.
*10 to 20% of patients will have GI side effects. So, a tablet with lower elemental iron may be tried.....or tablet may be tried with a small snack(accepting a somewhat reduced absorption)

10 comments:

  1. Hi, my name is Thiago Lacet, I´m a brazilian physician. Just here for congratulate you for the blog, the best medicine blog I find! Really a great work!!! Now, you have a new assiduous reader!

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  2. love your blog upon which I have just stumbled; as a mature ID specialist from Canada I don't have time to update my General Medicine as often as I'd like; now one of my kids is about to start a 5 yr residency - I'll be sure to direct to your site

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  3. Great blob. Thanks

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