RBC disorders

Question 1

clinical parameters used in testing for anemia include:

Answer 1

red cell count, hemoglobin concentration, and hematocrit

Question 2

mechanisms of anemia

Answer 2

blood loss, decreased RBC production, and decreased RBC survival

Question 3

young, healthy subjects can tolerate rapid loss of _____ of blood with few symptoms, but some will have a ____ response

Answer 3

500-1000 mL (up to 15-20% of total blood volume); vasovagal response (sweating, weakness, nausea, slow HR, and hypotension)

Question 4

rapid loss of _____ of blood produces shock

Answer 4

2000-2500 mL

Question 5

the loss of RBCs stimulates increased production, mediated by ____, resulting in an increase in the ____ count in the peripheral blood

Answer 5

erythropoietin; reticulocyte

Question 6

hemolytic anemias are characterized by _____ and retention of products of ______

Answer 6

shortened RBC survival; RBC destruction (iron)

Question 7

RBC destruction can occur in the ____ or in the ______

Answer 7

circulation (intravascular hemolysis); reticuloendothelial system (extravascular hemolysis)

Question 8

a decrease in _____ is a key feature of intravascular hemolysis

Answer 8

serum haptoglobin

Question 9

extravascular hemolysis involves destruction of RBCs in the reticuloendothelial system including the ____ and ____

Answer 9

spleen; liver

Question 10

hemolytic anemias are classified by the mechanism of RBC destruction into _____ which are usually inherited and _____ which are usually acquired abnormalities

Answer 10

intrinsic defects ; extrinsic defects

Question 11

mechanisms of intrinsic defects

Answer 11

membrane defects
abnormal hemoglobin
lack of globin chains
metabolic defect

Question 12

mechanisms of extrinsic defects

Answer 12

immune destruction
mechanical trauma
infections

Question 13

a membrane defect is an inherited defect in the RBC membrane that results in _____ of the RBC, so that they are ____ and _____ in the spleen

Answer 13

less deformability; sequestered; destroyed

Question 14

the specific membrane defect can be a qualitative or quantitative deficiency of ____, a structural protein of the cytoskeleton

Answer 14

spectrin

Question 15

example of a membrane defect disorder

Answer 15

hereditary spherocytosis (type of extravascular hemolysis)

Question 16

example of abnormal hemoglobin disorder

Answer 16

sickle cell anemia (extravascular hemolysis)

Question 17

an inherited defect (autosomal codominant) that results in diminished or absent synthesis of either the alpha or beta globin chains of hemoglobin

Answer 17

thalassemia (extravascular hemolysis)

Question 18

decreased globin production, as in thalassemia, results in decreased hemoglobin production, and _____ is the principal clinical manifestation

Answer 18

anemia

Question 19

example of metabolic defect disorder

Answer 19

glucose-6-phosphate dehydrogenase (G6PD) deficiency (extravascular hemolysis)

Question 20

cytomorphologic hallmark of G6PD deficiency

Answer 20

“bite” cells

Question 21

this disorder, also called hemolytic disease of the newborn (HDN), is caused by blood group incompatibility between the mother and fetus

Answer 21

erythroblastosis fetalis (extravascular hemolysis)

Question 22

absorption of vitamin B12 requires _____, a protein produced by ____ of the gastric mucosa

Answer 22

intrinsic factor; parietal cells

Question 23

IF-B12 complex passes to the _____ where it attaches to receptors on ____ and is absorbed

Answer 23

distal ileum; epithelial cells

Question 24

the absorbed B12 is bound to ______ in plasma which deliver it to the liver and other cells via the bloodstream

Answer 24

transcobalamins (transport proteins)

Question 25

folate is absorbed in the _____

Answer 25

proximal small intestine

Question 26

in aplastic anemia, a ____ abnormality results in marked reduction of ______

Answer 26

stem cell; hematopoiesis

Question 27

in aplastic anemia, production of all cellular elements of the blood is markedly decreased, which is called _____; aplastic anemia also has markedly decreased _____

Answer 27

pancytopenia; bone marrow cellularity

Question 28

two major pathogenic theories of aplastic anemia

Answer 28

• an acquired defect in stem cell production (decreased production of all types of blood cells)
• suppression of stem cells by T lymphocytes

Question 29

caused by autoantibodies to parietal cells and intrinsic factor

Answer 29

pernicious anemia

Question 30

B12 deficiency is associated with _____

Answer 30

atrophic gastritis

Question 31

pernicious anemia associated with loss of _____, ____, and _____

Answer 31

gastric parietal cells, achlorhydia, and deficient IF

Question 32

half of the cases of aplastic anemia are idiopathic and the remainder are caused by ____, ____, or ____

Answer 32

drugs (chloramphenicol), toxins (benzene), viral hepatitis

Question 33

decreased production of RBCs due to replacement of marrow elements by tumor (metastasis my myeloma) or fibrosis; platelets often also decreased

Answer 33

myelophthistic anemia

Question 34

the opposite of anemia; an increase in red cell mass

Answer 34

polycythemia

Question 35

_____ occurs with hemoconcentration from dehydration, vomiting, diarrhea, or excessive use of diuretics; _____ can be a primary or secondary phenomenon

Answer 35

relative polycythemia; absolute polycythemia

Question 36

stimuli which increase production of _____ can produce secondary absolute polycythemia

Answer 36

erythropoietin

Question 37

primary absolute polycythemia occurs when there is a non-regulated (neoplastic) proliferation of red cells and myeloid cells, called a _____

Answer 37

polycythemia vera

Question 38

_____ are helpful in distinguishing primary from secondary cases of absolute polycythemia

Answer 38

erythropoietin levels-
primary (normal or suppressed)
secondary (increased levels)

Question 39

____ and ____ are two leading causes of ischemia-related death in sickle cell anemia patients

Answer 39

acute chest syndrome and stroke

Question 40

what is the hallmark of autoimmune hemolytic anemia`

Answer 40

spherocytes

Question 41

most common cause of anemia worldwide

Answer 41

iron deficiency anemia

Question 42

in iron deficiency anemia, RBCs become ____ and contain _____ than usual

Answer 42

smaller (microcytic); less hemoglobin (hypochromic)

low MCV and MCHC