IRON - PowerPoint PPT Presentation

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IRON

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Title: IRON


1
IRON
  • M.Prasad Naidu
  • MSc Medical Biochemistry, Ph.D,.

2
Iron (Fe)
  • 2 types of body iron
  • heme iron
  • hemoglobin, myoglobin, catalases, peroxidases,
    cytochromes (a, b and c involved in electron
    transport), cytochrome P450 (involved in drug
    metabolism)
  • non-heme iron
  • ferritin, hemosiderin, hemofuscin, transferrin,
    ferroflavoproteins, aromatic amino acid
    hydroxylases
  • food iron is also classified as heme and non-heme

3
Food iron
  • heme iron
  • meats
  • poultry
  • fish
  • 20-23 of heme-iron is absorbable
  • non-heme iron
  • vegetables
  • fruits
  • legumes
  • nuts
  • breads and cereals
  • only 3 on non heme iron is absorbed

4
Iron absorption
  • occurs in upper part of small intestine
  • about 10 of food iron is absorbed
  • requires gastric HCl (releases ionic iron)
  • also requires copper
  • ferrous is better absorbed than ferric form
  • Fe forms chelates with ascobic acid, certain
    sugars and amino acid

5
Iron distribution and storage
  • carried in blood stream via transferrin (a b
    globulin)
  • stored in 2 forms
  • ferritin (a water soluble complex consisting of a
    core of ferric hydroxide and a protein shell
    (apoferritin)
  • hemosiderin (a particulate substance consisting
    of aggregates of ferric core crystals)
  • stored in liver, spleen, bone marrow, intestinal
    mucosal cells and plasma

6
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7
Iron elimination
  • there is no mechanism for excretion of iron
  • iron is normally lost by exfoliation of
    intestinal mucosal cells into the stools
  • trace amounts are lost in bile, urine and sweat
    (no more than 1 mg per day)
  • bleeding (vaginal, intestinal) is a more serious
    mechanism of elimination

8
IRON DEFICIENCY
  • Initial symptoms are vague and ill-defined
  • easy fatigability
  • lack of appetite
  • headache
  • dizziness
  • palpitations
  • then hypochromic-microcytic anemia
  • microcytosis (small RBCs)
  • hypochromia (poor fill of hemoglobin)
  • poikilocytosis (bizarre shapes)
  • anisocytosis (variable sizes)

9
IRON DEFICIENCY
  • Causes
  • excessive blood loss (parasitic, accidental,
    menstrual) is most common cause
  • rapid growth in children with limited intake of
    iron
  • malabsorption
  • gastric resection
  • sprue
  • increased metabolic requirement
  • pregnancy, lactation or neoplasia

10
Diagnosis of iron deficiency
  • hematology (microcytic hypochromic cells)
  • low serum iron
  • low serum ferritin( indicates low body stores)
  • in some conditions (inflammation, hepatitis)
    ferritin may be high
  • low hemosiderin
  • high total iron binding capacity (TIBC)

11
Iron absorption
  • average diet contains 10 - 15 mg of iron perday
  • a normal person absorbs 5 -10 of this iron or
    0.5 - 1.0 mg daily
  • iron absorption increases in response to low iron
    stores
  • menstruating women 1 - 2 mg per day
  • pregnant women 3 - 4 mg per day
  • absorption is via active process

12
Different types of iron
  • Ferrous sulfate 20
  • Exsiccated ferrous sulfate
  • ferrous gluconate 11.6
  • ferrous fumarate 33
  • ferrocholinate 12
  • polysaccharide-iron complex
  • iron dextran (Imferon)

13
Treatment of iron deficiency
  • give 200 - 400 mg of iron per day
  • up to 25 of the iron preparation may be absorbed
  • 50 - 100 mg of iron may be utilized in case of
    deficiency
  • give on an empty stomach
  • enteric coated iron tablet should not be used
    since we want absorption to occur in the stomach
    and proximal duodenum

14
Treatment of iron deficiency
  • parenteral iron is used in patients who have had
    bowel resections or in cases of inflammatory
    bowel disease
  • normally given IM (painful) Z-track minimizes
    tatoo
  • oral iron causes black stools, constipation,
    cramping
  • do not administer with antacids or metal
    chelators (tetracyclines)

15
Acute iron toxicity
  • common in small children ingesting large doses
    of soluble iron compounds
  • toxicity is usually divided into 4 phases
  • 1. 30 - 60 min. following ingestion
  • abdominal pain
  • nausea and vomiting
  • signs of acidosis and cardiovascular collapse may
    be seen

16
Acute iron toxicity
  • 2. Period of improvement - last about 8 to 16
    hours
  • 3. Period of progressive cardiovascular collapse
    (about 24 hrs after ingestion)
  • convulsions
  • coma
  • high mortality
  • 4. Gastrointestinal obstruction from scarring of
    stomach and small intestine

17
Deferoxamine mesylate (DFOM)
A chelating agent which reacts with ferric ion to
form a 11 chelate known as ferrioxamine Marketed
as Desferal Injection (Ciba) Produced by
Streptomyces pilosus
18
Chronic iron toxicity
  • causes
  • hereditary hemochromatosis
  • hemosiderosis
  • symptoms
  • cirrhosis iron deposition in the liver
  • diabetes iron deposit in the pancreas (damage to
    beta cells)
  • skin pigmentation
  • cardiac failure
  • treatment phlebotomy ( 1 unit of blood removes
    about 250 mg of iron

19
THANK YOU
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