35 Clinical Manifestations and Classification of Erythrocyte Disorders

Question 1

In an average person, the red cell mass must provide the total body tissues with approximately _________ of oxygen to support life

Answer 1

0.25 L/min

Question 2

The oxygen-carrying capacity of normal blood is

Answer 2

1.34 mL/g of hemoglobin (approximately 0.2 L/L of normal blood)

Question 3

Its actions include respiratory control, transcriptional regulation of glycolytic enzyme genes, angiogenesis, and energy metabolism

Answer 3

Hypoxia-Inducible Transcription Factors (HIFs)

Question 4

The major regulator of EPO production

Answer 4

HIF-2

Question 5

Two principal negative regulators of HIFs

Answer 5

• Von Hippel–Lindau tumor suppressor (VHL)
• Prolyl hydroxylase domain-containing proteins (PHD), PHD2 (encoded by EGLN1)

Question 6

In hypoxia, energy is produced by less efficient glycolysis accomplished by upregulation of transcription of glycolytic enzyme genes and increased glucose transport, a process known as the

Answer 6

Pasteur effect

Question 7

The Pasteur effect and its exception in the metabolism observed in malignant tissue, referred to as the

Answer 7

Warburg effect

Question 8

“Hemoglobin’s oxygen binding affinity is inversely related both to acidity and to the concentration of carbon dioxide”

Answer 8

Bohr effect

Question 9

In chronic anemia, increased oxygen tissue delivery is accomplished by increased amounts of _______________________

Answer 9

2,3-bisphosphoglycerate

Question 10

In acute anemia, the major donor areas for redistribution of blood are the

Answer 10

Mesenteric and iliac beds

Question 11

In chronic anemia in humans, the donor areas are the

Answer 11

Cutaneous tissue and the kidney

Question 12

In an otherwise healthy person, a measurable increase in resting cardiac output does not occur until hemoglobin concentration is less than ________ g/L

Answer 12

Less than 70 g/L

Question 13

TRUE OR FALSE

The rate of EPO synthesis is inversely and logarithmically related to hemoglobin concentration

Answer 13

TRUE

The rate of EPO synthesis is inversely and logarithmically related to hemoglobin concentration

Question 14

Anemia can be classified, based on determination of the red cell mass

Answer 14

(1) relative
(2) absolute

Question 15

Characterized by a normal total red cell mass in an increased plasma volume, resulting in a dilution anemia, a disturbance in plasma volume regulation

Answer 15

Relative anemia

Question 16

All anemias should be divided into anemias caused by decreased production and anemias caused by increased destruction of red cells.

The differentiation is based largely on the _______

Answer 16

Reticulocyte count

Question 17

Morphologic classification subdivides anemia into

Answer 17

• (1) macrocytic anemia
• (2) normocytic anemia
• (3) microcytic hypochromic anemia

Question 18

TRUE OR FALSE

The viscosity of blood decrease logarithmically with an increase in hematocrit

Answer 18

FALSE

The viscosity of blood increases logarithmically with an increase in hematocrit

Question 19

TRUE OR FALSE

Absolute erythrocytosis is not normovolemic but is accompanied by increased blood volume, which in turn enlarges the vascular bed and decreases peripheral resistance.

Answer 19

TRUE

Absolute erythrocytosis is not normovolemic but is accompanied by increased blood volume, which in turn enlarges the vascular bed and decreases peripheral resistance.

Question 20

TRUE OR FALSE

The presence of secondary gout and splenomegaly are usually signs of erythrocytosis rather than myeloproliferative neoplasm.

Answer 20

FALSE

The presence of secondary gout and splenomegaly are usually signs of a myeloproliferative neoplasm rather than of erythrocytosis alone.

Question 21

TRUE OR FALSE

EPO-driven erythrocytosis is generally associated with increased platelet production.

Answer 21

FALSE

EPO-driven erythrocytosis is generally not associated with increased platelet production.

Question 22

Cyanosis can result from

Answer 22

40–50 g/L of deoxygenated hemoglobin
15 g/L of methemoglobin
5 g/L of sulfhemoglobin

Question 23

TRUE OR FALSE

Hematocrit does not on its own increase thrombotic risk unless the somatic or germline mutations causing polycythemia and erythrocytosis, respectively, also promote thrombosis

Answer 23

TRUE

Hematocrit does not on its own increase thrombotic risk unless the somatic or germline mutations causing polycythemia and erythrocytosis, respectively, also promote thrombosis

Question 24

TRUE OR FALSE

Erythrocytosis pose a risk in surgical patients.

Answer 24

FALSE

Erythrocytosis does not pose a risk in surgical patients.

Question 25

TRUE OR FALSE

In polycythemia vera, however, it has been advocated that normalization of red cell mass should be accomplished before surgery, but firm data supporting this practice are lacking .

Answer 25

TRUE

In polycythemia vera, however, it has been advocated that normalization of red cell mass should be accomplished before surgery, but firm data supporting this practice are lacking .

Question 26

Erythrocytosis, is a condition in which the hematocrit percentage is above the upper limits of normal: higher than ______ in men and ______ in women

Answer 26

51% in men

48% in women

Question 27

Red cell mass is normal but the plasma volume is decreased

Answer 27

Relative erythrocytosis

Differentiation of absolute from relative erythrocytosis can be difficult at hematocrit levels lower than 60%.

Question 28

Red cell mass is increased above normal

Answer 28

Absolute erythrocytosis

Differentiation of absolute from relative erythrocytosis can be difficult at hematocrit levels lower than 60%.

Question 29

Primary Erythrocytosis and Polycythemia

Answer 29

Acquired somatic (polycythemia vera)

Inherited germline mutations (such as gain-of-function EPOR mutations expressed within hematopoietic progenitors)- Primary familial and congenital erythrocytosis/ polycythemia (PFCP)

Question 30

Caused by augmentation of erythropoiesis by circulating stimulatory factors such as EPO that is hypoxia induced (eg, high altitude, lung disease), EPO-producing tumors, or cobalt and manganese toxicity

Answer 30

Secondary erythrocytosis

Question 31

Caused by inherited mutations of the VHL gene, have elevated or inappropriately normal EPO levels in relation to elevated hematocrit

Answer 31

Chuvash erythrocytosis

Prone to develop thrombosis, have elevated pulmonary pressure, and have increased mortality independent of the increase in hematocrit

Question 32

Gene mutation in:
Erythrocytosis from HIF2α
Erythrocytosis from PHD2

Answer 32

Erythrocytosis from HIF2α : EPAS1
Erythrocytosis from PHD2: EGLN1