Chapter 14 - RBC key concepts

Question 1

Autosomal dominant disorder caused by mutations that affect the red cell membrane skeleton, leading to loss of membrane and eventual conversion of red cells to spherocytes, which are phagocytosed and removed in the spleen

Answer 1

Hereditary Spherocytosis

Question 2

Manifested by anemia, splenomegaly

Answer 2

Hereditary Spherocytosis

Question 3

Autosomal codominant disorders caused by mutations in α- or β-globin that reduce hemoglobin synthesis, resulting in a microcytic, hypochromic anemia.

Answer 3

Thalassemias

Question 4

Unpaired α-globin chains form aggregates that damage red cell precursors and further impair erythropoiesis.

Answer 4

β-thalassemia

Question 5

Autosomal recessive disorder resulting from a mutation in β-globin that causes deoxygenated hemoglobin to self-associate into long polymers that distort the red cell

Answer 5

Sickle Cell Anemia

Distortion of the red cell = sickling

Question 6

Blockage of vessels by sickled cells causes pain crises and tissue infarction, particularly of the marrow and spleen

Answer 6

Sickle Cell Anemia

Question 7

Red cell membrane damage caused by repeated bouts of

red cell shape distortion, resulting in a moderate to severe hemolytic anemia

Answer 7

Sickle Cell Anemia

Question 8

X-linked disorder caused by mutations that destabilize ____ enzyme, making red cells susceptible to oxidant damage

Answer 8

Glucose-6-Phosphate Dehydrogenase Deficiency

Question 9

Caused by antibodies against either normal red cell con- stituents or antigens modified by haptens (e.g., drugs)

Answer 9

Immunohemolytic Anemias

Question 10

Antibody binding results in either red cell opsonization and extravascular hemolysis or (uncommonly) complement fixation and intravascular hemolysis

Answer 10

Immunohemolytic Anemias

Question 11

Caused by deficiencies of folate or vitamin B12 that lead to inadequate synthesis of thymidine and defective DNA replication

Answer 11

Megaloblastic Anemia

Question 12

Results in enlarged abnormal hematopoietic precursors , ineffective hematopoiesis, macrocytic anemia, and (in most cases) pancytopenia

Answer 12

Megaloblastic Anemia

Enlarged abnormal hematopoietic precursors are called megaloblasts.

Question 13

Associated with neurologic damage, particularly in the posterior and lateral tracts of the spinal cord

Answer 13

Megaloblastic Anemia - B12 deficiency

Question 14

Caused by chronic bleeding or inadequate nutritional intake; results in insufficient hemoglobin synthesis and hypochromic, microcytic red cells

Answer 14

Iron Deficiency Anemia

Question 15

Caused by inflammatory cytokines, which increase hepcidin levels and thereby sequester iron in macrophages, and also suppress erythropoietin production

Answer 15

Anemia of Chronic Disease

Question 16

Caused by bone marrow failure (hypocellularity) due to diverse causes, including exposures to toxins and radiation, idiosyncratic reactions to drugs and viruses, and inherited defects in telomerase and DNA repair

Answer 16

Aplastic Anemia

Question 17

Acute: Parvovirus B19 infection (may persist in immunosuppressed patients)

Answer 17

Pure Red Cell Aplasia

Question 18

Chronic: Associated with thymoma, large granular lymphocytic leukemia, presence of neutralizing antibodies against erythropoietin, and other autoimmune phenomenon

Answer 18

Pure Red Cell Aplasia

Question 19

These cause what: 
Marrow replacement (tumors, granulomatous disease; so-called myelophthisic anemias), renal failure, endocrine disorders, liver failure

Answer 19

Other causes of underproduction anemias

Question 20

Caused by autoantibodies against platelet antigens

Answer 20

Immune Thrombocytopenic Purpura

Question 21

May be triggered by drugs, infections, or lymphomas, or

may be idiopathic

Answer 21

Immune Thrombocytopenic Purpura

Question 22

Both manifest with thrombocytopenia, microangiopathic hemolytic anemia, and renal failure;
- fever and CNS involvement are more typical of ___.

Answer 22

Thrombotic Thrombocytopenic Purpura and Hemolytic Uremic Syndrome

TTP

Question 23

Caused by acquired or inherited deficiencies of ADAMTS 13, a plasma metalloprotease that cleaves very- high-molecular-weight multimers of von Willebrand factor (vWF). Deficiency of ADAMTS 13 results in abnormally large vWF multimers that activate platelets.

Answer 23

TTP - Thrombotic Thrombocytopenic Purpura

Question 24

Caused by deficiencies of complement regulatory proteins or agents that damage endothelial cells, such as a Shiga-like toxin elaborated by E. coli strain O157:H7. The abnormalities initiate platelet activation, platelet aggregation, and microvascular thrombosis.

Answer 24

HUS - Hemolytic Uremic Syndrome

Question 25

Autosomal dominant disorder caused by mutations in a large protein that promotes the adhesion of platelets to subendothelial collagen

Answer 25

Von Willebrand Disease

Question 26

Typically causes a mild to moderate bleeding disorder resembling that associated with thrombocytopenia

Answer 26

Von Willebrand Disease

Question 27

X-linked disorder caused by mutations in factor VIII. Affected males typically present with severe bleeding into soft tissues and joints and have a PTT.

Answer 27

Hemophilia A

Question 28

X-linked disorder caused by mutations in coagulation factor IX. It is clinically identical to hemophilia A.

Answer 28

Hemophilia B

Question 29

Syndrome in which systemic activation of the coagulation leads to consumption of coagulation factors and platelets

Answer 29

Disseminated Intravascular Coagulation

Question 30

Can produce bleeding, vascular occlusion and tissue hypoxemia, or both

Answer 30

Disseminated Intravascular Coagulation

Question 31

Common triggers: sepsis, major trauma, certain cancers, obstetric complications

Answer 31

Disseminated Intravascular Coagulation

Question 32

Mean Cell Volume

Answer 32

Avg volume of red cell

Question 33

Mean Cell Hgb

Answer 33

Avg content (mass) of Hg per red cell, expressed in picograms.

Question 34

Mean Cell Hemoglobin Concentration

Answer 34

avg concentration of hemoglobin in a given volume of packed red cells

Question 35

Red Cell Distribution Width

Answer 35

Variation of red cell volume

Question 36

**Hypoxia can cause was in liver, myocardium, and kidney?

Answer 36

***Fatty change!!!