1. MLAB 1415- Hematology Keri Brophy-Martinez
Iron Metabolism and Hypochromic Anemias

2. Iron Metabolism Primary function Oxygen transport and storage
Distribution
Types of iron-containing compounds
Functional, assisting in enzymatic and metabolic functions
Transportation or storage
Location
RBCs- majority here
Macrophages of spleen& liver- where destruction of RBC occurs, liberating iron
Hepatocytes and enterocytes- storage of iron

3. Iron Metabolism Iron absorption and storage is influenced by:
The amount and type of available iron in the diet
Is it a nutritional deficiency
Incomplete absorption due to GI tract problems
Current iron stores
Increased demand (pregnancy, the growth years)
Excessive loss due to acute or chronic hemorrhage
menstrual period for women of childbearing years, GI bleeding for men

4. Forms of Iron Nonheme Heme Ionic or ferric
Found in vegetables and whole grains
Heme
Found in red meats
Easily absorbed

5. Iron Metabolism Transport Transferrin
Transports iron to bone marrow to be used in hgb synthesis
Synthesized in the liver
Storage
Primarily in the liver
Ferritin
Soluble iron, quick release for heme synthesis
Hemosiderin
Partially degraded iron, slow release

6. Iron Balance Loss of iron Regulation of iron
Secretions of urine, bile , sweat and exfoliation of intestinal epithelial cells of GI tract
Approx. 1 mg/ day
Regulation of iron
Delicate balance between loss and absorption

7. Laboratory Assessment of Iron
Serum iron
Total iron binding capacity (TIBC)
Percent saturation
Serum ferritin

8. Clinical Syndromes of Iron Metabolism
Iron Deficiency Anemia (IDA)
AKA Sideropenic anemia
This is the most common form of anemia.
IDA occurs when the iron stores in the body are inadequate to preserve homeostasis.

9. Causes of IDA
Dietary
Blood Loss
Hemodialysis
Malabsorption

10. 3 Stages of IDA Stage 1 Decrease in storage iron (ferritin decrease)
No anemia
RBC morphology normal
RDW can be elevated
Stage 2
Decrease in iron for erythropoiesis
No anemia or hypochromia
RBC slightly microcytic
Stage 3
Decrease in Blood Hgb
Decrease in peripheral tissue oxygen delivery
All lab tests abnormal
Microcytic, hypochromic anemia

11. Clinical Features of IDA
SOB
Lethargy
Pallor
Gastritis
Pica
Koilonychia

12. IDA: Lab features Decreased RBC, Hgb, Hct, MCV, MCH, MCHC
Normal to decreased
Retic
Peripheral blood smear
microcytic-hypochromic
Targets, elliptocytes, teardrops
If IDA is caused by bleeding, leukocytosis and thrombocytosis are possible.

13. IDA: Lab Findings Chemistry Bone marrow Decrease in stainable iron
Mild-moderate erythroid hyperplasia
M:E ratio decreased
Chemistry
Decrease in serum iron and ferritin
Increased TIBC

14. Anemia of Chronic Inflammation
Anemia that occurs in patients with chronic infections, chronic inflammatory disorders, trauma, organ failure or neoplasms
Occurs due to biochemical changes during inflammation
Hepcidin- acute phase reactant
Hallmark is normal- increased ferritin but low serum iron

15. Anemia of Chronic Inflammation: Lab Features
Typical lab findings
Decreased
RBC, Hgb, Hct, MCV, MCH, serum iron, transferrin
Normal to Increased
ferritin
Normal
MCHC
Normal to Decreased
Retic, TIBC
Peripheral blood smear
normocytic-normochromic
Targets, elliptocytes, teardrops
Bone marrow
M:E ratio increased

16. Anemia’s Associated with Abnormal Heme Synthesis
Sideroblastic Anemia
Lead Poisoning
Porphyrias

17. Sideroblastic Anemia (SA)
First step in heme synthesis is affected
Characterized by:
Increase in total body iron
Presence of ringed sideroblasts in bone marrow
Hypochromic anemia

18. Classification Sideroblastic anemia Hereditary Acquired 2 Forms
Idiopathic
Secondary type
Certain therapeutic drugs
Chronic transfusions (for aplastic anemia, leukemia, thalassemia)
Alcoholism and food fads
Use of iron utensils or increased iron in water .

19. Sideroblastic anemia Mechanism
Adequate iron but it can not be incorporated into hgb synthesis.
Iron enters mitochrondria of metarubricyte, but accumulates leading to formation of ringed sideroblasts
Eventually, mitochrondria rupture

20. Lead poisoning Lead interferes with iron storage in the mitochondria
Lead damages the activity of enzymes used for heme synthesis
Basophilic stippling pronounced

21. Lead Poisoning

22. Lab features of SA Peripheral blood Pappenheimer bodies
Hypochromic, normochromic RBCs
Normal to increased platelets
Chemistry
Increased serum iron, ferritin
Decreased TIBC

23. Hemochromatosis
Condition caused by increased iron absorption which deposits in vital organs such as the liver, spleen and pancreas which then becomes fibrotic
Hyperpigmentation of skin
Therapy consists of iron removal by therapeutic phlebotomy or chelation

24. Lab Features of Hemochromatosis
Increased
Iron
Ferritin
Decreased
TIBC
Transferrin

25. Porphyrias
Excessive production of porphyrins in the bone marrow (or liver)
Rare disease caused by accumulation of porphyrins in developing RBC’s
Defect in one or more of the enzymes in heme synthesis pathway
Characterized by dermal photosensitivity and rash caused by the sun. The original werewolf was probably a person with erythropoietic porphyria.

26. References
Harmening, D. M. (2009). Clinical Hematology and Fundamentals of Hemostasis. Philadelphia: F.A Davis.
McKenzie, S. B., & Williams, J. L. (2010). Clinical Laboratory Hematology . Upper Saddle River: Pearson Education, Inc.