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Blood and Lymph > Anemia- Iron Deficiency > Flashcards

Anemia- Iron Deficiency Flashcards

1
Q

Define: Anemia

A

Anemia is defined as insufficient red cell mass to adequately deliver oxygen to peripheral tissues .

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2
Q

Name three common factors that cause variations in hemoglobin

A
  1. Age. Infants >Adults>Children & Menstrating Women
  2. Sex
  3. Geography
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3
Q

Name three measurements you can use to define the existence of anemia.

A
  1. Hematocrit
  2. Hemoglobin
  3. Red Blood Cell Count
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4
Q

What is reticulocyte count?

A

of reticulocytes/ 1000 RBC

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5
Q

Define Reticulocyte index

A

Measurement of the production of red cells and is a way to correct the reticulocyte count for red cell concentration and stress reticulocytosis. It provides a ratio of how many fold beyond baseline the production of red cells is

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6
Q

What is the equation for reticulocyte index?

A

RI = Reticulocyte Count * (Patient Hgb/ Normal Hgb) * (1 / Stress Factor)

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7
Q

What are the stress factors?

A

Stress factor = 1.5 (mild anemia > or equal to 9 gm/ dl)

  1. 0 (moderate anemia 6.5 - 9)
  2. 5 (severe
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8
Q

What does an RI of less than 1 mean?

A

Anemia indicates decreased production of reticulocytes and therefore red blood cells.

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9
Q

What does an RI of > 2 mean?

A

Anemia indicates loss of red blood cells (destruction, bleeding, etc) leading to compensatory production of reticulocytes to replace the lost red blood cells

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10
Q

What is the absolute reticulocyte count?

A

Percent of reticulocytes * the red cell count. It is helpful in determining the relevance of the reticulocyte count.

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11
Q

What is the normal range for reticulocyte count?

What is the normal range for absolute reticulocyte count?

A

0.4-1.7%

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12
Q

Would you find an increase of 2,3-DPG within the cells of chronic anemia or acute anemia?

A

Chronic. These cells have time to establish this increase which makes the dissociation of oxygen to tissues more efficient to compensate for low oxygen carrying capacity

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13
Q

What symptoms would you be likely to find in someone with anemia that developed acutely?

A 
Symptoms include:
Shortness of breath
fatigue
rapid heart rate
dizziness 
claudication or pain with exercise 
pallow
Physicals  signs may include:
tachycardia
tachypnea
dyspnea and pallor
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14
Q

Iron exists in two valence states, what are they?

A

Ferric (3+) and Ferrous (2+)

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15
Q

Is iron soluble in aqueous solutions?

A

Not unless bound to specific proteins or other compounds

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16
Q

True or False: Iron balance is controlled primarily by excretion.

A

False. It is controlled by absorption. There is no active mechanism for excreting iron from the body the losses are small each day.

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17
Q

Where is the majority of iron found in the body?

A

65% associated with hemoglobin
25% Primary storage as ferritin and hemosiderin
6% Myoglobin

18
Q

Name two things that maintain solubility of iron while i the stomach.

A
  1. Low gastric pH

2. Gastroferrin (iron binding protein)

19
Q

Where does the absorption of iron take place?

A

Duodenum

20
Q

What is the function of duodenal cytochrome b-like protein (DCYTB)?

Where is it found?

A

Function: Converts ferric iron to ferrous iron through surface reductase activity

Location: Apical side of the duodenum

21
Q

What is the function of DMT1?

A

It is a divalent metal iron transporter that transports iron into the cell.

22
Q

What is ferritin?

A

Storage form of iron. It is a complex structure with a coat composed of 24 subunits alternating heavy (H) or light (L) chains the center of which contains 4500 atoms of Fe

23
Q

What is the function of ferroportin?

Where is it found?

A

Function: Baso-lateral ferrous iron transporter

Location: Baso-lateral side of duodenal cell

24
Q

What is hephaestin?

A

Enzyme located on the baso-lateral side that oxidizes iron to the ferric form allowing it to bind to apotransferrin.

25
Q

Name two things that can enhance absorption of Fe.

Name two things that can inhibit absorption of Fe.

A
  1. Presence of amino acids in the duodenum
  2. Vitamin C- by maintaining valence state of Fe
    * also erythropoietin and increased iron in the diet
  3. Phytates
  4. Oxalates
26
Q

Describe transferrin and its function

A

Transferrin is a 84kDa plasma protein produced in the liver which binds two moles of iron in the ferric form at high specificity and affinity. It is the main transporter of iron to the marrow to maturing normoblasts.

27
Q

Erythocytes live for about 120 days. What happens to the iron inside the erythrocytes when they die?

A

Erythrocytes are removed from circulation by macrophages in the spleen which sequester the ferritin stores. Eventually the storage pool may be released from the cell and bound by transferrin again…..IT’S THE CIRCLE OF LIFE (HEY HEY) AND IT MOVES US ALLLLLLLLLLLL

28
Q

What is the function of hepcidin?

A

It binds to ferroportin and causes its degredation

29
Q

Where is hepcidin produced?

A

Hepcidin is a 25 amino acid peptide that is produced in the liver in response to high iron intake and inflammation

30
Q

When hepcidin levels are high what happens to the levels of saturated transferrin?

A

Since the flow of iron from cells to plasma is decreased so to is the saturation of transferrin

31
Q

Explain how iron enters the maturing normoblast.

A

Transferrin binds to the transferrin receptor on maturing normoblast and is inaginated via clathrin coated pits that form an endosome.

The endosome gets acidified releasing the iron from transferring

Iron exits the endosome via the divaelent metal ion transporter (DMT1)

Transferrin and receptor is brought back up to the surface and apotransferrin in released

32
Q

What population is most at risk for iron deficiency anemia?

A

Infants and toddlers

Women (adolescent females and post-menopausal females)

33
Q

What should be on the differential diagnosis when you suspect iron anemia?

A
  1. Chronic inflammation or infection
  2. Chronic Disease
  3. Thallassemia
  4. Sideroblastic anemias
34
Q

Normalization of parameters in iron administration is slow. List in chronological order what normalizes

A
  1. Serum Iron
  2. Reticulocyte (3-5 Days)
  3. Hemoglobin (7-10 Days)
  4. MCV, Erythrocyte protophyrin, and RDW (because erythrocytes lifespan is 120 days)
35
Q

Name three etiologies of iron overload.

A
  1. Increase in iron intake
  2. Increased absorption (mutation in HLA-H
  3. Repeated transfusions for chronic anemia
36
Q

What is the role of the HLA-H gene in iron overload?

A

Encodes for a protein in duodenal crypt cell which acts as a cofactor for absorption leading to increased absorption

37
Q

What target organs are damaged by iron overload?

A
  1. Heart
  2. Liver
  3. Endocrin
38
Q

What is hemochromatosis?

A

A disorder that leads to increased absorption of iron

39
Q

What is the treatment for hemochromatosis?

A

Therapeutic phlebotomy when initially diagnosed. Followed by maintenance phlebotomy periodically for the rest of their life

40
Q

What causes hemosiderosis?

A

Transfusions

41
Q

What is prescribed for iron overload caused by frequent transfusion?

A

Desferal or Exjade they are iron chelators

Blood and Lymph (22 decks)

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