Hypochromic Anemias

Question 1

Name 3 classifications of Anemia

Answer 1

1. Disorders of Iron metabolism
2. Disorders of Heme Synthesis (sideroblastic anemias)
3. Disorders of Globin Synthesis

Question 2

List 2 types of Disorders of iron Metabolism

Answer 2

1. Iron deficiency anemia
2. anemias of chronic disease

Question 3

List 3 causes of iron deficiency anemia

Answer 3

1. decreased dietary iron
2. blood loss
3. impaired iron transport

Question 4

List 2 causes of anemia of chronic disease

Answer 4

1. chronic inflammatory disease
2. malignant disorders

Question 5

List 3 types of disorders of Heme synthesis (Sideroblastic Disease)

Answer 5

1. Heretitary sideroblastic anemias
2. idiopathic sideroblastic anemias
3. Secondary sideroblastic anemias

Question 6

List three causes of secondary sideroblastic anemia

Answer 6

1. drug induced
2. alcohol induced
3. lead poisoning

Question 7

List 3 disorders of globin synthesis

Answer 7

1. β thal
2. α thal
3. other thalessemias

Question 8

List the functions of iron

Answer 8

1. formation of heme in hgb and myoglobin
2. components of cytochromes, catalses , myeloperoxidase
3. enzyme activator in some reactions

Question 9

State the total body iron in normal adults

Answer 9

total iron in adults 2-5 grams

males: 3.5g

females 2.3g

Question 10

list 3 iron compartments and the distribution in each

Answer 10

1. Heme {enymes, Hgb, myoglobin} 80%
2. Transport: transferrin 0.1%
3. Storage: spleen, liver etc 20%

Question 11

List 3 factors which influence iron absorption

Answer 11

1. serum iron concentration (inverse relationship)
2. amount in diet (direct)
3. pH in gut (acid pH enhances absorption)

Question 12

Describe transferrin

Answer 12

transferrin is a β-globulin which carries two Fe³⁺ / molecule

Question 13

Function of transferrin

Answer 13

transports iron in plasma from macrophages to developing normoblasts in bone marrow

Question 14

Define transferrin saturation

Answer 14

the % of iron binding sites on transferrin which are occupied by iron

Question 15

describe ferritin

Answer 15

main storage form of iron

is the water soluble and labile storage form found in nucleated rbcs, intestinal mucosal cells, blood plasma and in macrophages mostly in liver and spleen

this form is not visible under Perl’s Prussian blue stain

Question 16

Describe hemosiderin

Answer 16

a type of storage iron

less labile than ferritin and is water insoluble

formed in macrophages by polymerization and processing of many ferritin molecules into large, dense aggregates

visible on Perl’s Prussian blue

Question 17

Describe the excretion of iron

Answer 17

there is NO normal physiologic mechanisms designed to excrete iron

Question 18

How is iron lost in a normal person

Answer 18

Fe is lost in small amounts each day

men and postmenopausal women: feces by desquamation, perspiration, and minute hemorrhages for a total loss of about 1mg/day

fertile but non pregnant females: due to menstrual loss 2mg/day

Pregnant women: diversion of iron to fetus loss = 3mg/day

Question 19

Dietary requirements of iron

Answer 19

men and post menopausal women: 10mg

infants and children: 5 mg

menstruating women: 20 mg

Pregnant women: 30 mg

Question 20

list the 5 main causes of Fe Deficiency

Answer 20

1. Chronic bleeding (most frequent cause)
2. decreased absorption of irom
3. dietary deficiency
4. increased requirements for iron
5. decreased or abnormal transferrin (rare)

Question 21

Describe iron deficiency anemia

Answer 21

Fe deficiency results in decreased heme formation in nRBC and hypochromia and microcytosis of mature rbc

Question 22

Define hypochromia

Answer 22

rbcs with increases size of central pallor indicating they contain less Hgb than normal

Question 23

Define microcytosis

Answer 23

more cell divisions that occur while waiting for the cell to fill up with hgb which results in cells that are smaller than normal

Question 24

Three stages of the development of iron deficiency

Answer 24

1. iron depletion: iron stores are reduced by not absent
2. iron deficiency: iron stores are depleted to almost zero, the serum iron and transferring sat are decreased, and TIBC is increased
3. Iron deficiency anemia: hgb decreased with hypo and micro

Question 25

List the lab findings in iron deficiency anemia

Answer 25

Peripheral blood: * hgb: ↓ * hct: ↓ * rbc count: normal * rbc indices: MCV, MCH, MCHC all ↓ * RDW: ↑ * RBC Morphology: micro hypo in mild cases plus in severe cases can get ovalocytes and target cells * Retic count: normal or sl ↑ * WBC count/morph: normal or sl ↑ due to chronic bleeding * Plt count/morph normal or sli ↑ (chronic bleed) Serum Chemistries: * Iron assay: ↓ * TIBC: ↑ * Transferrin Sat:↓ * Ferritin: ↓ * sTfR (soluble transferrin receptor): ↑ * FEP (free erythrocyte protoporphyrin): ↑

Question 26

Define Thalassemia

Answer 26

group of disorders in which the rate of synthesis of a specific type of polypetide chain (α or β) used in globin production is decreased seen as micro hypo anemia

Question 27

Define Sideroblastic anemia

Answer 27

anemia caused by a biochemical abnormalities in the sythesis of heme in developing red cells Note: not due to a lack of Fe Most cases involve abnormal enzyme functions in the synthesis of heme. Iron accumulates in these because less than normal amts of protoporphyrin IX is formed.

Question 28

What are 2 major categories of Sideroblastic anemias:

Answer 28

1. Refractory sideroblastic anemias (poor response to therapy) inherited and idiopathic 2. Secondary sideroblastic anemia * due to vit B6 (pyridoxine) deficiency: required for coenzyme in first rx of heme synthesis * due to drugs toxins chemicals etc: inhibit heme synthesis eg: lead poisoning

Question 29

What are the lab findings in Sideroblastic anemia

Answer 29

1. Ringed sideroblasts in bone marrow (nRBC containing prussian blue staining, iron loaded mitochondria and siderotic granules) 2. Hypochromia and normocytic, macrocytic or morphology 3. Basophilic stippling and possible pappenheimer bodies 4. increased serum iron, transferrin sat and serum ferritin; TIBC is usually normal or decreased 5. Monocytosis seen sometimes

Question 30

Define Anemia of Chronic Disease

Answer 30

sometimes anemia is seen in chronic inflammatory diseases eg: * chronic infection * autoimmune disorders, * renal failure * chronic leukemias * endocrine disorders Morphology: normochromic and normocytic

Question 31

Causes of Anemia of Chronic Disease

Answer 31

1. An inflammatory blockage of the release of iron stores from macrophages in the liver and spleen due tot he action of cytokines associated witht eh inflammatory response. the inability to release iron stores results in usually mild accumulation of iron in the storage areas and a deficiency of iron inside the developing red cells 2. increased hemolysis of circulating red cells 3. decreased erythropoietin production

Question 32

What are the lab findings in Anemia of Chronic Disorders?

Answer 32

* hypochromia or normochromia * normocytic * decreased iron and transferrin saturation * Normal or increased storage iron * Serum ferritin is normal or increased * Serun sRfR is normal * Hgb rarely less than 90g/L * MCV is usually slightly low or low normal (75-80fL)