Disorders of RBCs

Question 1

Where does hematopoiesis occur in the fetus at 3 weeks, 3 months, and the third trimester

Answer 1

At 3 weeks, in the yolk sac
3 months, kidney
3rd trimester, occurs in the bone marrow

Question 2

What type of bone has hematopoietic marrow and where is it contained?

Answer 2

Spongy bone in the intratubular space

Question 3

What is the formula to determine cellularity of the bone marrow?

Answer 3

100%-age

Question 4

What is erythropoietin and where is it produced?

Answer 4

A growth factor that stimulates differentiation of red blood cells, made in the kidney

Question 5

What is the name for the cell in the last stage of RBC production in the bone marrow?

Answer 5

Orthochromatic erythroblast

Question 6

A reticulocyte will show what kind of staining? Due to?

Answer 6

Polychromatic staining due to RNA machinery

Question 7

What is hematocrit?

Answer 7

The volume of red blood cells per unit of blood expressed as a percentage

Question 8

What are the two ways of classifying anemia?

Answer 8

Red cell morphology and underlying mechanism

Question 9

What are the two mechanisms for anemia?

Answer 9

Increase in RBC loss or decrease in production

Question 10

Where does RBC destruction occur in extravascular hemolysis?

Answer 10

Spleen and liver

Question 11

What causes intravascular hemolysis, is it more or less common than extravascular?

Answer 11

mechanical forces or biological agents, less common

Question 12

What substance levels change in intravascular hemolysis?

Answer 12

Increased lactate dehydrogenase and decreased haptoglobin

Question 13

What is immunohemolytic anemia?

Answer 13

When there is premature destruction of RBCs due to antibodies binding to them

Question 14

What test is used to determine one has hemolytic anemia?

Answer 14

The Coombs test

Question 15

What are the two types of immunohemolytic anemia?

Answer 15

Warm and cold antibody

Question 16

In the warm type what Ig is present? At what temperature are they active?

Answer 16

IgG, 37 degrees C

Question 17

What is the primary cause of the warm type?

Answer 17

Idiopathic

Question 18

Which drugs can cause the warm type?

Answer 18

Penicillin and alpha-methyldopa

Question 19

How do you treat the warm type?

Answer 19

Intravenous Ig, prednisone, and splenectomy as a last resort

Question 20

In the cold type, what Ig is present? Describe the mechanism for this disease?

Answer 20

IgM, the IgM causes C3b to bind to the RBCs. When the RBCs reach warmer areas of the body the IgM is lost but the C3b remains which activates the complement system. The RBCs are then destroyed in the spleen and liver

Question 21

Acute and chronic cases of the cold type are associated with?

Answer 21

Acute with infectious agents, chronic with lymphoma or they can be idiopathic

Question 22

What are the sites for bone marrow biopsy?

Answer 22

The tibia in neonates and the sternal crest in adults

Question 23

What is the most common hereditary hemolytic anemia in the world?

Answer 23

Sickle cell anemia

Question 24

What causes sickle cell?

Answer 24

A point mutation on the 6th position of the beta globin gene substituting a valine for a glutamate

Question 25

Autosplenectomy as seen in sickle cell leads to increased susceptibility to infection by?

Answer 25

Encapsulated organisms

Question 26

What is the most common cause of death in children with sickle cell?

Answer 26

Septicemia and meningitis

Question 27

What leads to an aplastic crises in those with sickle cell?

Answer 27

Transient cessation of erythropoiesis due to infection of erythroid progenitor cells by parovirus B19

Question 28

What can be used to raise HbF levels and reduce the symptoms of aplastic crises?

Answer 28

Hydroxyurea

Question 29

What causes thalassemias?

Answer 29

Genetic defects leading to decreased synthesis of either the alpha or beta chains of HbA

Question 30

What happens to the production of the unaffected chain?

Answer 30

It exists in relative excess

Question 31

Where is thalassemia endemic?

Answer 31

To areas where malaria is common such

Question 32

What happens in beta thalassemia?

Answer 32

In beta zero there is no production of the beta chain and in beta plus there is decreased production

Question 33

Describe the pathogenesis of beta thalassemia

Answer 33

Alpha chains aggregate and Hb level decreases as a result, RBCs are then destroyed by the spleen, systemic iron overload is possible

Question 34

What are the 4 types of alpha thalassemia?

Answer 34

Silent carrier is when there is one gene for the alpha chain missing Alpha thalassemia trait is when two genes are missing Hemoglobin H disease is when 3 are missing Hydrops fetalis is when 4 are missing (the fetus will usually die in utero)

Question 35

Megaloblastic anemia stems from deficiencies in?

Answer 35

b12 and folate

Question 36

What is the term used for anemia as a result of folate deficiency?

Answer 36

Pernicuous anemia

Question 37

What manifestations are seen in the oral cavity as a result of anemia?

Answer 37

Atrophic glossitis, angular chelitis, and apthous stomatitis Atrophy of the lingual papillae, fissuring of the oral commissures, and canker sores respectively

Question 38

What is pancytopenia and why does it lead to hyperplasia of bone marrow?

Answer 38

When there is a reduced cell count in all lines not just RBCs. There is an increase in erythropoietin and this causes marrow to produce precursors for all cell lines and leads to hyperplasia

Question 39

During digestion B12 binds to what substance in the stomach?

Answer 39

Haptocorrin

Question 40

After B12 is released from the B12 haptocorrin complex it binds to?

Answer 40

Intrinsic factor

Question 41

What substance in the plasma does B12 bind to allowing it to be transported to the rest of the body?

Answer 41

Transcobalamin

Question 42

What is a site for storage of B12?

Answer 42

The liver

Question 43

What is the most frequent cause of B12 deficiency?

Answer 43

Pernicuous anemia

Question 44

What is pernicious anemia?

Answer 44

An autoimmune attack on gastric mucosa and the intrinsic factor itself

Question 45

What will you see in the stomach and intestine in someone who has pernicious anemia?

Answer 45

Intestinal metaplasia, presence of goblet cells in the stomach, and atrophic glands

Question 46

How does pernicious anemia affect the CNS?

Answer 46

Demyelination of the dorsal and lateral tracts of the spinal cord

Question 47

What are possible causes of B12 deficiency other than pernicious anemia?

Answer 47

Decreased intake, increased need such as in pregnancy or cancer, gastrectomy so no IF is made, and a fish tapeworm

Question 48

What is folate used for?

Answer 48

Intermediate in carbon transfer during purine synthesis, specifically thymidine

Question 49

How does the megaloblastic anemia as a result of folate deficiency differ from B12?

Answer 49

No neurological changes

Question 50

How is folate deficiency diagnosed?

Answer 50

Decreased levels of folate deficiency in the blood and increased homocysteine level

Question 51

What is an antagonist of folate that can inhibit absorption?

Answer 51

Methotrexate

Question 52

What is the most common cause of anemia?

Answer 52

Iron deficiency

Question 53

What is the etiology or cause of iron deficiency?

Answer 53

Lack of it in diet, celiac disease or gastrectomy, increased requirements, or chronic blood loss

Question 54

The levels of what substance in plasma correlates with total body iron stores?

Answer 54

Ferritin

Question 55

What delivers iron to erythroid precursors?

Answer 55

Transferrin

Question 56

Why regulates iron metabolism?

Answer 56

Hepcidin

Question 57

What does hepcidin inhibit that reduces iron uptake?

Answer 57

Ferriportin

Question 58

Hepcidin has the effect of suppressing release of iron from

Answer 58

macrophages

Question 59

Anemia of chronic disease is most often seen in ?

Answer 59

Hospital settings

Question 60

Inflammatory mediators such as ____ cause anemia because they stimulate production of?

Answer 60

IL-6, hepcidin, prevents the release of iron from macrophages

Question 61

What is aplastic anemia?

Answer 61

A syndrome of bone marrow failure due to suppression of multi potent stem cells

Question 62

What inherited disease can cause aplastic anemia?

Answer 62

Fanconi anemia

Question 63

What is the pathogenesis of aplastic anemia?

Answer 63

The stem cell attacked by environmental insult and becomes genetically altered leading to attack by T cells or decrease in proliferation

Question 64

In aplastic anemia only one cell line is initially affected but over time all of them are, this is called?

Answer 64

Pancytopenia

Question 65

Is the spleen enlarged in aplastic anemia?

Answer 65

No never