Chapter 14 - RBC key concepts Flashcards
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.
Thalassemias
Unpaired α-globin chains form aggregates that damage red cell precursors and further impair erythropoiesis.
β-thalassemia
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
TTP
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
Common triggers: sepsis, major trauma, certain cancers, obstetric complications
Disseminated Intravascular Coagulation
Mean Cell Volume
Avg volume of red cell
Mean Cell Hgb
Avg content (mass) of Hg per red cell, expressed in picograms.
Mean Cell Hemoglobin Concentration
avg concentration of hemoglobin in a given volume of packed red cells
Red Cell Distribution Width
Variation of red cell volume
**Hypoxia can cause was in liver, myocardium, and kidney?
***Fatty change!!!
