RBC disorders Flashcards

1
Q

clinical parameters used in testing for anemia include:

A

red cell count, hemoglobin concentration, and hematocrit

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2
Q

mechanisms of anemia

A

blood loss, decreased RBC production, and decreased RBC survival

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3
Q

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

A

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

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4
Q

rapid loss of _____ of blood produces shock

A

2000-2500 mL

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5
Q

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

A

erythropoietin; reticulocyte

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6
Q

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

A

shortened RBC survival; RBC destruction (iron)

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7
Q

RBC destruction can occur in the ____ or in the ______

A

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

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8
Q

a decrease in _____ is a key feature of intravascular hemolysis

A

serum haptoglobin

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9
Q

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

A

spleen; liver

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10
Q

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

A

intrinsic defects ; extrinsic defects

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11
Q

mechanisms of intrinsic defects

A

membrane defects
abnormal hemoglobin
lack of globin chains
metabolic defect

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12
Q

mechanisms of extrinsic defects

A

immune destruction
mechanical trauma
infections

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13
Q

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

A

less deformability; sequestered; destroyed

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14
Q

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

A

spectrin

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15
Q

example of a membrane defect disorder

A

hereditary spherocytosis (type of extravascular hemolysis)

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16
Q

example of abnormal hemoglobin disorder

A

sickle cell anemia (extravascular hemolysis)

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17
Q

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

A

thalassemia (extravascular hemolysis)

18
Q

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

19
Q

example of metabolic defect disorder

A

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

20
Q

cytomorphologic hallmark of G6PD deficiency

A

“bite” cells

21
Q

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

A

erythroblastosis fetalis (extravascular hemolysis)

22
Q

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

A

intrinsic factor; parietal cells

23
Q

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

A

distal ileum; epithelial cells

24
Q

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

A

transcobalamins (transport proteins)

25
folate is absorbed in the _____
proximal small intestine
26
in aplastic anemia, a ____ abnormality results in marked reduction of ______
stem cell; hematopoiesis
27
in aplastic anemia, production of all cellular elements of the blood is markedly decreased, which is called _____; aplastic anemia also has markedly decreased _____
pancytopenia; bone marrow cellularity
28
two major pathogenic theories of aplastic anemia
- an acquired defect in stem cell production (decreased production of all types of blood cells) - suppression of stem cells by T lymphocytes
29
caused by autoantibodies to parietal cells and intrinsic factor
pernicious anemia
30
B12 deficiency is associated with _____
atrophic gastritis
31
pernicious anemia associated with loss of _____, ____, and _____
gastric parietal cells, achlorhydia, and deficient IF
32
half of the cases of aplastic anemia are idiopathic and the remainder are caused by ____, ____, or ____
drugs (chloramphenicol), toxins (benzene), viral hepatitis
33
decreased production of RBCs due to replacement of marrow elements by tumor (metastasis my myeloma) or fibrosis; platelets often also decreased
myelophthistic anemia
34
the opposite of anemia; an increase in red cell mass
polycythemia
35
_____ occurs with hemoconcentration from dehydration, vomiting, diarrhea, or excessive use of diuretics; _____ can be a primary or secondary phenomenon
relative polycythemia; absolute polycythemia
36
stimuli which increase production of _____ can produce secondary absolute polycythemia
erythropoietin
37
primary absolute polycythemia occurs when there is a non-regulated (neoplastic) proliferation of red cells and myeloid cells, called a _____
polycythemia vera
38
_____ are helpful in distinguishing primary from secondary cases of absolute polycythemia
erythropoietin levels- primary (normal or suppressed) secondary (increased levels)
39
____ and ____ are two leading causes of ischemia-related death in sickle cell anemia patients
acute chest syndrome and stroke
40
what is the hallmark of autoimmune hemolytic anemia`
spherocytes
41
most common cause of anemia worldwide
iron deficiency anemia
42
in iron deficiency anemia, RBCs become ____ and contain _____ than usual
smaller (microcytic); less hemoglobin (hypochromic) | low MCV and MCHC