Chapter 3 Red Blood Corpuscles

Question 1

What is Anemia?

Answer 1

It is the decrease in the oxygen carrying power of the blood either due to decrease in the number of RBC’s or decrease in the hemoglobin content in the blood.

Question 2

When is the number of RBC and hemoglobin count number that shows that anemia is present?

Answer 2

RBC: 4.5 million microliters in males and 3.9 million microliters in females.
Hemoglobin count: 13.5 g/dl in males and 11.5 g/dl in females.

Question 3

What are blood indices?

Answer 3

Certain measurements that give us information that help diagnosis of types and causes of anemia. They can give the hematocrit value, red cell count, and Hb content.

Question 4

What are types of blood indices?

Answer 4

MCH, MCV, MCHC.
MCH: Mean corpuscular hemoglobin
MCV: Mean Corpuscular volume
MCHC: mean corpuscular hemoglobin concentration

Question 5

MCH

Answer 5

Mean Corpuscular Hemoglobin tells you the amount of hemoglobin in a single RBC.
(Hemoglobin content/ RBC count) x10.

Question 6

What is the normal value of MCH?

Answer 6

25-32 picograms.
Less than 25 picograms is hypo-chromic.

Question 7

MCV

Answer 7

Mean corpuscular volume tells the volume of a single RBC’s.
(Hematocrit/RBC count)x10.

Question 8

What is the normal value of MCV?

Answer 8

80-95 microcubes
Less than 80 would result in microcytes and more than 95 results in macrocytes.

Question 9

MCHC

Answer 9

Mean Corpuscular Hemoglobin Concentration gives you the measure of hemoglobin in 100 ml of packed RBC’s.
(Hemoglobin count/ hematocrit)x100

Question 10

What is the normal number of MCHC?

Answer 10

32-38 g/dl
Any value less than 32 is hypochromic anemia. If it’s within the normal range it is normochromic.

Question 11

Anemia can be classified according to:

Answer 11

Hb content and size.

Question 12

What are the types of Anemia?

Answer 12

1. Normocytic normochromic anemia.
2. Microcytic hypochromic anemia (iron deficiency anemia)
3. Macrocytic anemia (megaloblastic anemia)

Question 13

What is normocytic normochromic anemia?

Answer 13

The decrease of RBC mass and HB Content but MCH and MCV are within normal ranges.

Question 14

What happens in normocytic normochromic anemia?

Answer 14

1. Acute blood loss (hemmorage), the liver can replace plasma loss in two days while the bone marrow cannot compensate for Red cell loss simultaneously, thus they become diluted in the plasma.
2. Bone marrow depression.
3. Hemolytic anemia ( excessive hemolysis of RBC’s), jaundice is usually present.
4. Hemolytic anemia may be due to intrinsic or extrinsic disorders.

Question 15

What are the types of intrinsic disorders?

Answer 15

1. Hereditary spherocytosis
2. G6PD enzyme deficiency
3. Sickle cell anemia

Question 16

What is hereditary spherocytosis?

Answer 16

The red cells are spherocytes and hemolyse more readily than normal biconcave cells. It is due to the mutation in proteins that maintain flexibility of membrane RBC.

Question 17

G6PD

Answer 17

The susceptibility of red cells to hemolysis by oxidizing agents is increased due to the deficiency of enzyme glucose. 6-phosphate dehydrogenase.
1. G6PD catalyzes the initial step oxidation of glucose via certain pathways.
2. This pathway generates NADH which is needed for the maintenance of normal red cell fragility.
3. When blood is exposed to oxidizing agent (drugs or food), ferrous is converted to ferric forming methemoglobin.
4. NADH methemoglobin reductase enzyme in RBC’s converts methemoglobin to hemoglobin. Congenital absence of this enzyme cause hereditary methemoglobinemia.

Question 18

Sickle cell anemia

Answer 18

Where normal hemoglobin is replaced by HbS which precipitates inside the RBC’s at low O2 tension, giving the cell a sickle shape.

Question 19

Thalassemias

Answer 19

Microcytic hypochromic anemia that is due to the decreased or absence of alpha and beta chains of Hb.

Question 20

Extrinsic disorders

Answer 20

1. Antibodies against RBC as in incompatible blood transfusion and erythroblastic fetalis (Rh incompatibility).
2. Bacterial toxins.
3. Chemicals.
4. Drugs.

Question 21

What is Microcytic hypochromic anemia?

Answer 21

The decrease in the RBC mass and Hb content with MCV less than 80 micro-cubes and MCH less than 25 picograms. It is commonly known as iron deficiency anemia.

Question 22

What are types of iron deficiency anemia?

Answer 22

1. Deficiency of iron in diet.
2. Deficient iron absorption.
3. Chronic blood loss.

Question 23

Deficiency of iron in diet.

Answer 23

1. Due to a lower iron intake than the amount needed.
2. More common in growing children and during pregnancy.

Question 24

Deficient iron absorption

Answer 24

1. Partial gastronomy
2. Vitamin C deficiency
3. Much intake of phytic oxalates and phosphates
4. Diseases of the small intestines

Question 25

Chronic blood loss

Answer 25

1. Ankylostoma infestation
2. Peptic ulcer or piles
3. Excessive bleeding during menstruation in females

Question 26

Macrocytic anemia (megablastic anemia)

Answer 26

RBC mass and Hb content decrease but MCV> 95 micro-cubes.

Question 27

What are the causes of Macrocytic anemia?

Answer 27

Folic acid deficiency and vitamin 12 deficiency.

Question 28

Folic acid deficiency

Answer 28

1. Low intake in diet
2. Increased need as in pregnancy
3. Failure of absorption
4. Anti folate cytotoxic drugs (methotrexate)

Question 29

Vitamin B12

Answer 29

1. Defective absorption (as in after gastrectomy)
2. Absence of intrinsic factor (pernicious anemia)
3. Distal small intestine diseases

Question 30

What is pernicious anemia?

Answer 30

It is familial disease in elderly women cause by an immune reaction against parietal cells of the stomach.
It leads to destruction of the parietal cells so there is an absence of HCL and intrinsic factors.
1. Defective absorption of vitamin B12 resulting in Macrocytic anemia accompanied with nervous manifestations.

Question 31

Polycythemia

Answer 31

Increased number of RBC’s that may reach 6-8 million/mm3.

Question 32

What are the types of polycythemia?

Answer 32

Primary (Vera) polycythemia and secondary polycythemia.

Question 33

Primary polycythemia (Vera)

Answer 33

Condition in RBC forming organs and is usually accompanies with increased production of WBC’s and platelets.

Question 34

Secondary polycythemia

Answer 34

Tissues becoming hypoxic: obstructive lung diseases and subjects living in high altitudes.