BIIC Pathology Lecture 3_Microcytic, Macrocytic, and Aplastic Anemias

Question 1

What is transferrin?

Answer 1

It is an iron binding protein that is created in the liver and transports dietary iron through the blood to the locations of heme production

Question 2

In healthy individuals, what is the typical transterrin saturation and serum iron levels for men and women?

Answer 2

1/3 transferrin saturation. 120 ug/dL serum iron in men and 100 mg/dL serum iron in women

Question 3

What is ferritin?

Answer 3

It is a protein iron complex found in the spleen, bone marrow, liver, and skeletel muscle

Question 4

What are the 4 microcytic anemias?

Answer 4

Iron deficency
Anemia of chronic disease
Thalassemia
Sideroblastic anemia

Question 5

What are the two macrocytic anemias?

Answer 5

Folate deficiency (vitamin B9)
Vitamin B12 dificiency (cobalamine)

Question 6

What is the most common nutritional deficency in the world?

Answer 6

Iron deficiency

Question 7

What are the 4 mechanisiums that result in insuficient nutriant in the body?

Answer 7

1) dietary lack
2) Malabsorbtion
3) Increased demands (cancer)
4) Blood loss

Question 8

What percentage of ingested iron is absorbed into the body? What is the required daily intake for men and women?

Answer 8

Only 10-15% of ingested iron is absorbed. Men need 7-10mg daily and women need 7-20 mg (premenopause women are on the higher end)

Question 9

What conditions can cause malabsorbtion of Iron?

Answer 9

sprue, chronic diarrhea, gastrectomy, and celiacs.

Question 10

What is the most common cause of iron deficiency in the developed world? What clinical significance does this have?

Answer 10

Chronic bleeding is the most common cause. This means, any iron deficency in men or postmenopausal women must be treated as a GI bleed until proven otherwise

Question 11

What are Four key clinical findings in iron deficiency anemia?

Answer 11

low serum iron levels, low ferritin level, and low transferrin saturation, and disappearance of stainable iron bone marrow macrophages (this is seen with prussian blue stains).

Question 12

What are the three histologic findings of iron deficiency anemia?

Answer 12

expanded cental palor, hypocromatic, and poikilocytosis (pencil cells)

Question 13

What is the most common anemia in hospitalized patients

Answer 13

anemia of chronic disease

Question 14

What is the MOA of Anemia of chronic Disease

Answer 14

Inflammatory cytokines like IL-6 cause elevated levels of hepcidin which block the transfer of iron to erythroid precursers and thus suppress erythropoesis

Question 15

What is the MOA of Macrocytic anemias?

Answer 15

Both folate and B12 are required for DNA synthesis (they are required to make thymidine). Without them DNA syntheis does not occure and this is seen most quickly in rapidly dividing cells. Because this effects the megaloblastic stem cells, this is often causes pancytopenia (low count of RBC, WBC, and platlets)

Question 16

What are two histologic findings of Macrocytic anemia? Which is the “early finding”

Answer 16

Macrocytic anemia presents with hypersegmented neutophils (an early finding) and macroovalocytes (egg shaped RBCs)

Question 17

What is the main cause of folate deficiency

Answer 17

typically inadequate dietary intake

Question 18

How does the manifestation of B12 deficiency differ from folate?

Answer 18

B12 Deficiency will often present with neurological banormalities (caused by demylination) as well.

Question 19

How can folate and and B12 macrocytic anemias be distinguished?

Answer 19

Measure serum and RBC levels of folate and B12

Question 20

How do B12 deficiencies typically arise?

Answer 20

They are most often a result of malaborbtion (can be intake in diets with no animal products)

Question 21

How many years of B12 can your liver store

Answer 21

5-20 years worth

Question 22

What is the main cause of malabsobtion of B12?

Answer 22

Perniciouse anemia which is an auto immune attack on the gastric mucosa so intrinsic factor is not produced and B12 is not absorbed. Other causes are gastrectomy, ileal resection, and conditions that effect the distal ilium like crohn’s

Question 23

What are the neurologic results of B12 deficiency?

Answer 23

Demylination of the posterior and lateral columns of the spinal cord.

Question 24

What is aplastic anemia?

Answer 24

It is a disorder in which multipotent myeloid stem cells are suppressed leading to pancytopenia. Histology of bone marrow is often devoid of hematopoetic elements

Question 25

What is the MOA of aplastic anemia?

Answer 25

65% of cases are idiopathic although some chemicals are known to cause it (benzene, chemotherapy) as well as some viral infections

Question 26

What is Fanconi anemia

Answer 26

A rear inherited aplastic anemia characterized by Marrow hypofunction becomes evident early in life, often accompanied by multiple
congenital anomalies, eg, hypoplasia of the kidney and spleen and bone anomalies,
which most commonly involve the thumbs or radii

Question 27

How does inherited defects of telomerase cause aplastic anemia?

Answer 27

The telomeres shorten prematurely and therefor become non functional leading to non functional hematopoetic precursors due to premature senescence

Question 28

What are the two major MOA of aplastic anemia?

Answer 28

✴ An extrinsic, immune-mediated suppression
of marrow progenitors
✴ An intrinsic abnormality of stem cells

Question 29

What is Pure Red Cell Aplasia

Answer 29

It is a condition where only RBC precursors are suppresed. Can be autoimmune or a result of parvo B19

Question 30

What is Myelophthistic Anemia

Answer 30

This is when hematopoesis is stopped because bone marrow is replaced by a space occupying legion

Question 31

How does renal failure cause anemia?

Answer 31

The kidney is what produces EPO. Without the kidney there will be now erythropoesis