Ch5 - 4) Normocytic anemia

Question 1

What is normocytic anemia?

Answer 1

Anemia with normal-sized RBCs (MCV = 80-100 um3)

Question 2

What is normocytic anemia due to?

Answer 2

increased peripheral destruction or underproduction

Question 3

How do you distinguish between the two etiologies of normocytic anemia?

Answer 3

Reticulocyte count

Question 4

What are reticulocytes?

Answer 4

Young RBCs released from the bone marrow,

Question 5

How are reticulocytes identified?

Answer 5

They appear on blood smear as larger cells with bluish cytoplasm (due lo residual RNA)

Question 6

What is the normal reticulocyte count (RC)?

Answer 6

1-2%.

Question 7

What is the RBC lifespan?

Answer 7

it is 120 days;

Question 8

What is the turnover of RBC’s?

Answer 8

each day roughly 1-2% of RBCs are removed from circulation and replaced by reticulocytes.

Question 9

How does a properly functioning marrow respond to anemia?

Answer 9

by increasing the RC to >3%.

Question 10

Is RC reliable in anemia?

Answer 10

RC is falsely elevated in anemia

Question 11

Why is RC falsely elevated in anemia?

Answer 11

It is measured as a percentage of total RBCs; decrease in total RBCs falsely elevates percentage of reticulocytes.

Question 12

How is RC corrected?

Answer 12

By multiplying reticulocyte count by Hct/45.

Question 13

What does a corrected RC count > 3% indicate?

Answer 13

good marrow response and suggests peripheral destruction.

Question 14

What does a corrected RC count < 3% indicate?

Answer 14

poor marrow response and suggests underproduction.

Question 15

What is peripheral vascular destruction divided into?

Answer 15

Divided into extravascular and intravascular hemolysis;

Question 16

What does peripheral vascular destruction result in?

Answer 16

both result in anemia with a good marrow response.

Question 17

Extravascular hemolysis involves what?

Answer 17

RBC destruction by the reticuloendothelial system (macrophages of the spleen, liver, and lymph nodes).

Question 18

What is the role of macrophages in extravascular hemolysis?

Answer 18

consume RBCs and break down hemoglobin

Question 19

What do macrophages break down globin into?

Answer 19

globin is broken down into amino acids.

Question 20

What is heme broken down into?

Answer 20

iron and protoporphyrin; iron is recycled.

Question 21

In the reticuloendothelial system what is protoporphyrin broken down into?

Answer 21

unconjugated biliruhin, which is bound to serum albumin and delivered to the liver for conjugation and excretion into bile.

Question 22

What does the clinical and laboratory findings include?

Answer 22

Anemia with splenomegaly, jaundice due to unconjugated bilirubin, and increased risk for bilirubin gallstones

Question 23

When would marrow hyperplasia occur with extravascular hemolysis?

Answer 23

Occurs with corrected reticulocyte count > 3%

Question 24

What does intravascular hemolysis involve?

Answer 24

The destruction of RBCs within vessels.

Question 25

What are the clinical and laboratory findings for intravascular hemolysis?

Answer 25

1) Hemoglobinemia. 2) Hemoglobinuria 3) Hemosiderinuria 4) Decreased serum haptoglobin

Question 26

Why is there hemosiderinuria in intravascular hemolysis?

Answer 26

Renal tubular cells pick up some of the hemoglobin that is filtered into the urine and break it down into iron, which accumulates as hemosiderin; tubular cells are eventually shed resulting in hemosiderinuria.