Chapter 14 - RBC key concepts Flashcards Preview

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Flashcards in Chapter 14 - RBC key concepts Deck (36)
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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

Hereditary Spherocytosis


Manifested by anemia, splenomegaly

Hereditary Spherocytosis


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



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



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

Sickle Cell Anemia

Distortion of the red cell = sickling


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

Sickle Cell Anemia


Red cell membrane damage caused by repeated bouts of
red cell shape distortion, resulting in a moderate to severe hemolytic anemia

Sickle Cell Anemia


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

Glucose-6-Phosphate Dehydrogenase Deficiency


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

Immunohemolytic Anemias


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

Immunohemolytic Anemias


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

Megaloblastic Anemia


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

Megaloblastic Anemia

Enlarged abnormal hematopoietic precursors are called megaloblasts.


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

Megaloblastic Anemia - B12 deficiency


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

Iron Deficiency Anemia


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

Anemia of Chronic Disease


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

Aplastic Anemia


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

Pure Red Cell Aplasia


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

Pure Red Cell Aplasia


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

Other causes of underproduction anemias


Caused by autoantibodies against platelet antigens

Immune Thrombocytopenic Purpura


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

Immune Thrombocytopenic Purpura


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

Thrombotic Thrombocytopenic Purpura and Hemolytic Uremic Syndrome



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.

TTP - Thrombotic Thrombocytopenic Purpura


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.

HUS - Hemolytic Uremic Syndrome


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

Von Willebrand Disease


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

Von Willebrand Disease


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.

Hemophilia A


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

Hemophilia B


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

Disseminated Intravascular Coagulation


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

Disseminated Intravascular Coagulation