Ineffective and Insufficient Erythropoiesis Flashcards
It is the term used for marrow erythroid proliferative activity
Erythropoiesis
Normal erythropoiesis occurs in bone marrow and is under the control of the hormone _____________ (produced by the kidney) and other growth factors and cytokinesis
erythropoietin
refers to the production of erythroid precursor cells that are defective
Ineffective erythropoiesis
defective precursors often undergo _________________ (programmed cell death) in the bone marrow before they have a chance to mature to the reticulocyte stage and be released into the peripheral circulation
apoptosis
It is an impaired deoxyribonucleic acid [DNA] synthesis as a result of vitamin B12 or folate deficiency
megaloblastic anemia
It is a deficient globin chain synthesis
thalassemia
It is a deficient protoporphyrin synthesis
sideroblastic anemia
Several conditions such as megaloblastic anemia, thalassemia, and sideroblastic anemia involve _____________________ as a mechanism of anemia
ineffective erythropoiesis
When peripheral blood hemoglobin concentration
is low, it triggers an increase in ____________________ leading to increased erythropoietic activity
erythropoietin production
refers to a decrease in the number of erythroid precursors in the bone marrow, resulting in decreased RBC production and anemia
Insufficient erythropoiesis
Factors that can lead to a decreased RBC production
- deficiency of Iron (inadequate intake, malabsorption, excessive loss from chronic bleeding)
- deficiency of erythropoietin (renal disease)
- loss of the erythroid precursors as a result of an autoimmune reaction (aplastic anemia, acquired pure red cell aplasia) or infection (parvovirus B19)
Erythropoiesis can also be suppressed by ___________
infiltration of the bone marrow space with leukemia
cells or with nonhematopoietic cells (metastatic tumors, granulomas, or fibrosis)
________________ with characteristic teardrop RBCs are formed with nonhematopoietic cells
myelophthisic anemia
Anemia can also develop as a result of ____________ (such as a traumatic injury) or _____________ (such as an intermittently bleeding colonic polyp)
acute blood loss. chronic blood loss
Increased hemolysis results in a shortened _____________, thus increasing the risk for anemia
RBC life span
Chronic blood loss induces ____________ as a cause of anemia
iron deficiency
With ________________, the bone marrow takes a few days to increase production of RBCs
acute blood loss and excessive hemolysis
A complete blood count (CBC) is performed using an ________________ to determine the RBC count, hemoglobin concentration, hematocrit, RBC indices, white blood cell count, and platelet count to detect the presence of anemia.
automated blood cell analyzer
The RBC indices include the ________________.
mean cell volume (MCV), mean cell hemoglobin (MCH), and mean cell hemoglobin concentration (MCHC)
The most important in the RBC indices is the _______________, a measure of the average RBC volume in femtoliters.
MCV
It is an index of variation of cell volume in an RBC population
red cell distribution width (RDW)
An RBC volume frequency distribution curve with the relative number of cells plotted on the ordinate and RBC volume (fL) on the abscissa
RBC histogram
Reading RBC histogram:
In healthy individuals the distribution is ______________.
In healthy individuals the distribution is approximately Gaussian
Reading RBC histogram:
Abnormalities include a shift in the curve to the _____________ (smaller cell population or microcytosis) or to the __________ (larger cell population or macrocytosis)
left, right
It is the coefficient of variation of RBC volume expressed as a percentage
RDW
It indicates the variation in RBC volume within the population measured
RDW
An increased RDW correlates with
anisocytosis (variation in RBC diameter) on the peripheral blood film
It serves as an important tool to assess the bone marrow’s ability to increase RBC production in response to an anemia
reticulocyte count
young RBCs that lack a nucleus but still contain residual ribonucleic acid (RNA) to complete the production of hemoglobin
reticulocytes
Reticulocyte count is determined by ________________
multiplying the percent reticulocytes by the RBC count
A patient with a severe anemia may seem to be producing ___________ numbers of reticulocytes if only the percentage is considered
increased
There are how many successive corrections that are made to the reticulocyte count to obtain a better representation of RBC production
2
To obtain a corrected reticulocyte count, one corrects for the degree of anemia by ___________
multiplying the reticulocyte percentage by the patient’s hematocrit and dividing the result by 45 (the average normal hematocrit)
It is a better indication of the rate of RBC production than is the corrected reticulocyte count.
reticulocyte production index (RPI)
state-of-the-art automated blood cell analyzers determine the fraction of immature reticulocytes among the total circulating reticulocytes, called the _____________
immature reticulocyte fraction (IRF)
It is helpful in assessing early bone marrow response
after treatment for anemia
IRF
Plays a crucial role in determining whether an anemia is due to an RBC production defect or to premature hemolysis and shortened survival defect
Analysis of the reticulocyte count
If there is shortened RBC survival, as in the hemolytic anemias, the bone marrow tries to compensate by increasing RBC production to __________ into the peripheral circulation
release more reticulocytes
Although an increased reticulocyte count is a hallmark
of the hemolytic anemias, it can also be observed after __________________
acute blood loss
Chronic blood loss does not lead to an appropriate increase in the reticulocyte count, but rather leads to _____________________________________
iron deficiency and a subsequent low reticulocyte count
An inappropriately low reticulocyte count results from _____________________
decreased production of normal RBCs
