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MEDEX Fall 17 - Path Exam 3 - Heme I
Terms in this set (82)
What is the hormone secreted by kidneys which stimulates the production of new RBCs in the bone marrow?
iron-containing protein in red blood cells which transports O2 molecules
What is the range for a RBC's life span?
immature red blood cells
What is the normal percentage of reticulocytes in total RBCs?
Reduction in the oxygen-transporting capacity of blood, which usually stems from a decrease in the red cell mass to subnormal levels.
Types of anemia by underlying mechanism
Increased destruction (hemolytic)
Impaired red cell production
In iron deficiency and thalassemia, how would you describe the red blood cells?
In folate or VitB12 deficiency, how would you describe the red blood cells?
• Caused by mutations that affect the red cell membrane skeleton
• Leads to loss of membrane and eventual conversion of red cells to spherocytes, which are phagocytosed and removed in the spleen
• Manifested by anemia, splenomegaly
Sickle Cell Anemia
• Results from a mutation in β-globin that causes deoxygenated hemoglobin to self-associate into
rs* that distort the red cell
• Blockage of vessels by sickled cells causes pain crises and tissue infarction, particularly of the marrow and spleen
• Red cell membrane damage caused by repeated bouts of sick- ling results in a moderate to severe hemolytic anemia
• Patients are at high risk for bacterial infections and stroke
• Caused by mutations in α- or β-globin that reduce hemoglobin synthesis in a microcytic, hypochromic anemia.
• In β-thalassemia, unpaired α-globin chains form aggregates that damage red cell precursors and further impair erythropoiesis.
Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency
disorder caused by mutations that destabilize G6PD, making red cells susceptible to
• Caused by antibodies against either normal red cell constituents or antigens modified by haptens (such as drugs)
• Antibody binding results in either red cell opsonization and extravascular hemolysis or (uncommonly) complement fixa- tion and intravascular hemolysis
Intravascular cause of hemolytic anemia
Characterized by injuries so severe that red cells literally burst within the circulation.
Intravascular hemolysis may result from mechanical forces (e.g., turbulence created by a defective heart valve) or biochemical or physical agents that severely damage the red cell membrane
Extravascular causes of hemolytic anemia
Extravascular hemolysis is caused by defects that increase the destruction of red cells by phagocytes particularly in the spleen.
In hereditary spherocytosis and sickle cell disease, how would you describe the red blood cells?
Normocytic but with abnormal shapes
mean cell volume MCV
the average volume per red cell, expressed in femtoliters
mean cell hemoglobin concentration MCHC
the average concentration of hemoglobin in a given volume of packed red cells, expressed in g/dl
Red Cell Distribution Width (RDW)
The coefficient of variation of red cell volume.
A parameter that measures variation in red blood cell size or red blood cell volume. RDW is elevated in accordance with variation in red cell size (anisocytosis).
ratio of the volume of red cells to the volume of whole blood
normal range of hematocrit in women
normal range of hematocrit in men
RBC's have less color than normal when examined (pale). Not enough hemoglobin in the red blood cells.
abnormally large nucleated RBC found especially in people with pernicious anemia or certain vitamin deficiencies.
abnormally small cell
abnormally large cell
What is the underlying mechanism in anemia caused by trauma, GI tract lesions, or gynecologic disturbances?
What is the underlying mechanism in hemolytic anemias?
Increased red cell destruction
What is the underlying mechanism in paroxysmal nocturnal hemoglobinuria?
Acquired membrane defect
In sickle cell anemia and thalassemia, what is the underlying abnormality or mechanism?
Hemoglobin synthesis / hereditary
What are two extrinsic factors in hemolytic anemias?
Antibody mediated or mechanical trauma
Anemias caused by accelerated red cell destruction are termed what?
Shortness of breath, organ failure and shock are clinical manifestations of what type of anemia?
Pallor, fatigue and lassitude are clinical manifestations of what type of anemia?
What type of chronic anemia is associated with hyperbilirubinemia jaundice and gallstones?
Anemias that stem from _______ manifest clinically with iron overload, heart and endocrine failure.
If left untreated, ____________ anemias such as thalassemia, result in growth retardation, skeletal abnormalities, and cachexia
What mechanism is impaired in aplastic anemia, pernicious anemia, megaloblastic anemia, thalassemias and acute leukemia?
The pattern of anemia characterized by normocytic and normochromic
hypovolemic shock results from what?
acute blood loss
What causes the pattern of anemia characterized by gradually depleted iron stores leading to chronic anemia?
chronic blood loss
The following are features shared by what type of anemia?
• Decreased red cell life span
• Compensatory increase in
• Retention of products of degraded red cells
Uncomplicated hemolytic anemia
The following are examples of what type of anemia?
• Hereditary spherocytosis
• Sickle cell anemia
• G6PD deficiency
• Immunohemolytic anemia
The most common familial hemolytic anemia in the world
Sickle cell anemia
An autosomal recessive disorder resulting from inherited mutations in the beta-globin gene, deoxygenation, and formation of polymers that distort the red cell
Sickle cell anemia
What is associated with erythroid hyperplasia in the marrow and increased numbers of reticulocytes in the peripheral blood?
The following cumulative events can create what?
• Repeated sickling episodes
• Distortion of the membrane
• Influx of calcium
• Loss of potassium and water
• Damage to membrane skeleton
Irreversibly sickled cells
Repeated episodes sickling with red cell membrane damage and dehydration causes what?
Chronic hemolytic anemia
What is a major consequence of sickle cell anemia that can result in ischemic tissue damage and pain crises?
Chronic hemolytic anemia and widespread microvascular obstructions are complications of what?
sickle cell anemia
What is a complication of sickle cell anemia that can be triggered by pulmonary infections or fat emboli from infarcted marrow?
acute chest syndrome
vaso-occlusive or pain crises
The most serious crisis that punctuates the course of sickle cell disease and occurs most commonly in the bone marrow, where it often progresses to infarction
What is the major complication of sickle cell anemia that sometimes occurs in the setting of acute chest syndrome
What disease causes patients to be functionally asplenic, making them susceptible to infections?
sickle cell disease
An acute event in sickle cell disease that is severe yet self-limited and is caused by a sudden decrease in red cell production.
Anemia caused by chronic bleeding, malabsorption, or inadequate diet. It results in insufficient hemoglobin synthesis and hypochromic, microcytic red cells.
iron deficiency anemia
Anemia caused by inflammatory cytokines, which increase hepcidin levels and thereby sequester iron in macrophages and suppress EPO production
Anemia of chronic disease
Caused by deficiencies of folate or vitamin B12 that lead to inadequate synthesis of thymidine and defective DNA replication
Results in enlarged abnormal hematopoietic precursors, ineffective hematopoiesis, macrocytic anemia, and pancytopenia
A circulating protein that binds and clears free hemoglobin.
A group of hereditary disorders caused by inherited mutations that lead to structural abnormalities in hemoglobin.
Sickle cell anemia is most prevalent.
Caused by bone marrow failure due to causes such as exposure to toxins and radiation, idiosyncratic reactions to drugs and viruses, and inherited defects in telomerase and DNA repair
Anemia that can be caused by resection of the terminal ileum or gastrectomy causing Vitamin B12 deficiency and neurologic complications
Denotes an increase in red cells per unit volume of peripheral blood, usually in association with an increase in hemoglobin concentration
Relative Polycythemia Vera
Reduced plasma volume
Results from dehydration, such as occurs with water deprivation, prolonged vomiting, diarrhea, or the excessive use of diuretics.
Absolute Polycythemia Vera
Absolute polycythemia is described as:
- Abnormal proliferation of myeloid stem cells, normal or low erythropoietin levels (polycythemia vera)
- Increased erythropoietin levels
: Lung disease, high-altitude living, cyanotic heart disease
: Erythropoietin-secreting tumors (e.g., renal cell
carcinoma, hepatomacellular carcinoma, cerebellar
What disease has clinical signs and symptoms that are related to an absolute increase in red cell mass and is associated with low levels of serum EPO
This disease causes thromboses and infarctions in the heart, spleen and kidneys as a result of increased viscosity and vascular stasis
What are three categories that can be abnormal in bleeding disorders?
Vessel wall, platelets and clotting factors
Bleeding due to __________ is characterized by spontaneous appearance of petechiae and ecchymoses in the skin and mucous membranes probably resulting from minor trauma.
Bleeding due to _________ show clinical signs that include easy bruising, excessive bleeding from minor trauma, and menorrhagia.
What bleeding disorder category does von Willebrand disease belong to? (to a greater degree)
platelet deficiency / thrombocytopenia
What bleeding disorder category do hemophilias belong to?
Coagulation factor defects
Caused by systemic activation of coagulation and leads to consumption of coagulation factors and platelets. Can be dominated by bleeding, vascular occlusion and tissue hypoxemia, or both.
Disseminated intravascular coagulation
Sepsis, OB complications, malignancy and major trauma are most often associated with what bleeding disorder?
Disseminated intravascular coagulation (DIC)
Autosomal dominant disorder that presents as spontaneous bleeding from mucous membranes, excessive bleeding from wounds and menorrhagia
Von Willebrand disease
What is the most common inherited bleeding disorder
Von Willebrand disease
Caused by autoantibodies against platelet antigens. May be triggered by drugs, infections, or lymphomas, or may be idiopathic
immune thrombocytopenic purpura
Autosomal dominant disorder caused by mutations in a large protein that promotes the adhesion of platelets to subendothelial collagen
Von Willebrand disease
hemophilia A is an X-linked disorder caused by mutation in what?
Bleeding disorder where affected males typically present with severe bleeding into soft tissues and joints
Most common hereditary cause of serious bleeding
Anemia caused by poor diet, alcoholism or increased metabolic needs
Folate deficiency anemia
THIS SET IS OFTEN IN FOLDERS WITH...
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