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Hematology Lecture 2: Bone Marrow
Terms in this set (79)
Pancytopenia of all precursor cells and bone marrow lacks active marrow.
What is the most common cause of aplastic anemia?
Drug toxicity reaction
Abnormal growth of cells
Systemic excessive accumulation of iron in the form of hemosiderin or ferritin within the macrophages or parenchyma
What are three reasons hemosiderosis would occur?
1. Increased Iron intake
2. Decreased Iron utilization
3. Increased destruction of RBC
When greater then 75% of marrow interstitial area is composed of hematopoietic cells
Hypercellular bone marrow
Increase in number of a particular lineage of precursor cells, can be either absolute or relative to other lineages
When less than 25% of marrow space consists of hematopoietic cells
Hypocellular bone marrow
Decrease in cell numbers of a particular lineage that can be absolute or relative compared to other cell lines
Hematopoietic production without complete maturation related to destruction of late stage forms or nutritional deficiency
Abnormal growth of cells in bone marrow related secondarily to viral infections, nutritional deficiencies, and drug-induced reactions
Reactive stromal condition to severe bone marrow injury with infiltration by reticulin and collagen fibers leading to peripheral cytopenias
Bone marrow with crowding out of normal hematopoietic elements by increased numbers of abnormal cells or stroma.
What conditions commonly cause myelophthisis
Excessive bone production
The calculated relationship between the number of granulocytic precursors divided by the number of erythroid precursors in bone marrow
M:E ratio (myeloid to erythroid ratio)
When the degree of hematopoietic cellularity within the marrow interstitial area is between 25% and 75%
Normocellular bone marrow
Reduction of all three cell lines in circulating blood
What are the main indications to perform bone marrow biopsies?
Cytopenia with unknown cause
Cytosis with unknown cause
Abnormal cells with unknown cause
Assess iron stores
Investigate leukemia or myeloma
Mast cell tumor staging
Metastatic neoplasia staging
FUO (fever unknown origin)
Pursuing IFA, IHC, PCR
What four things can be determined via bone marrow evaluation?
1. % of each cell type
2. iron stores
3. maturation of cells in each population
4. atypical morphology of cells
Suppression or destruction of hematopoietic cells would cause what on a CBC?
Cytopenia that can't be explained by mechanism of peripheral destruction
Suppression or destruction of hematopoietic cells causes what 3 conditions?
3 examples of what you may see on a CBC if there is suppression or destruction of hematopoietic cells
Poorly regen or non-regen persistant anemias
Replacement of normal cells by neoplastic cells in the bone marrow would show up as what on a CBC?
What two cancers cause the replacement of normal cells by neoplastic cells in the bone marrow?
What conditions can cause unexplained elevations in cell numbers?
Neoplasms causing excessive Epo secretion
If there is a marked thrombocytosis on a CBC what two conditions must you distinguish between?
Benign increases from Neoplastic conditions
What is an example of a neoplastic condition that causes thrombocytosis?
Essential thrombocythemia (increased number of abnormal megakaryocytes)
If you have an intramedullary plasma cell neoplasma (a type of myeloma) what do you see on the CBC?
Very high serum protein (specifically globulin)
Monoclonal Ig peak on electrophoresis
Term for when the leukocyte count exceeds 50,000/uL with marked left shift
When you have an extreme leukocytosis in the absence of an infection, abcess or tumor what are you looking for when you do a bone marrow biopsy?
When do you do a bone marrow biopsy to evaluate iron stores?
Only if other info doesn't distinguish between iron deficiency anemia and other causes of anemia
T/F You usually only do a biopsy to see iron stores in dogs because cats don't store iron in their bones
True, if there is iron in a cat bone then there is something wrong
When would you suspect Systemic occult neoplasia?
What Chemistry value is indicative of lymphoma?
What do you see on CBC with leukoerythroblastosis?
Concurrent immature granulocytes and nucleated RBC in circulation
What is leukoerythroblastosis indicative of?
Marrow damage from neoplastic infiltration
What are some diseases that settle in marrow causing problems?
Do young animals have more or less iron in their marrow and why?
Less iron in marrow
Rapidly use stores for erythropoiesis
Comment on the differences between cellularity in young animals vs. older animals
Young animals have higher cellularity with high erythroid predominance
As animal ages diaphysis is infiltrated with adipose decreasing the marrow cellularity
Why do you avoid the humerus when doing a biopsy on a young animal?
Due to proximity to the epiphyseal growth plate
T/F More than one cell line participates in the degree of marrow cellularity
True. Generally erythroid, myeloid and megakaryocytes
What must you take into consideration to determine if the degree of marrow cellularity is pathologic or physiologic?
Age of animal
When taking the M:E ratio, what cell line is counted for the M?
T/F hyperplasia of one line typically presents with hypercellularity
T/F hypoplasia of one line typically presents with mild to marked hypocellularity
False. it can cause hypocellularity, normocellularity, or hypercellularity, it depends on the other cell types
Decreased M:E ratio can be indicitive of what?
If you have a decreased ME ratio and a leukopenia on the CBC what do you have?
If you have a decreased ME and a regenerative anemia what do you have?
(Or rarely polycythemia vera)
If you have a decreased ME and a non-regenerative anemia and high erythroid count in marrow what do you have?
Increased ME ratio can indicate what 3 things?
If you have an increased ME ratio and concurrent leukocytosis what do you have?
If you have an increased ME with concurrent non-regen anemia what do you have?
If you have an increased ME ratio and concurrent leukopenia in CBC what do you have?
What are examples of things that cause drug induced bone marrow damage leading to aplasitic anemia?
Bracken fern poisoning
Absolute or relative decrease but NOT absence of functional tissue in bone marrow
What can cause hypoplasia?
Infections (FeLV, Parvo, FIV, Distemper)
Sertoli cell tumor (causes estrogen tox)
Chronic renal failure
What from the previous list causes hypoplasia of erythroid line alone?
Chronic renal failure (no EPO)
Intestinal malabsorption (iron)
Possibly Parvo virus
When you have hypoplasia of the erythroid line what happens to the ME
When you have hypoplasia of the granulocytic line what happens to the ME
Decreased or normal
what is the difference between aplasia and hypoplasia?
aplasia= complete absence of all cells lines and active marrow tissue in bone marrow (pancytopenia)
hypoplasia= absolute or relative decrease of cells and active marrow, but not absence
Both hypoplasia and aplastic anemia are related to what 4 things?
Insufficient numbers of stem cells
Abnormal hematopoietic microenvironment
Decreased stimulatory factors
Increased inhibitory regulatory factors (estrogen)
For both aplastic anemia and hypoplasia what do you expect on a CBC?
Granulocytopenia (typically neutropenia)
What is the most common cause of aplasia?
drug induced toxicosis (ex: estrogen toxicosis)
Why is it important to monitor CBC 5-7 days following the discovery of intense left shift in granulocytic precursors in bone marrow?
It takes 5-7 days for the bone marrow to regenerate the normal population of cells in the blood after loss or utilization. After this time, the left shift should be decreasing or going towards normal
Morphologic changes associated with myelotoxicity
Dohle body presence
Diffuse cytoplasmic basophilia (best recognized in late forms of granulocytes)
Foamy vacuolation with cytoplasmic basophilia
what are dohle bodies?
retained aggregates of RNA formed into basophilic clumps in the cytoplasm of RBC
Why do the morphologic changes with myelotoxicity happen?
From Altered development of bone marrow precursor cells
From gram neg endotoxemia
what can cause injury to the bone marrow?
what happens to the bone marrow after mild injury?
the bone marrow becomes reactive due to non specific immune response. There will be an increase in plasma cells, lymphocytes, mast cells, macrophages, and eosinophils in the bone marrow
What are some consequences of moderate to marked marrow injury?
Improper release of bone marrow precursors
Improper production of bone marrow precursors
what does the bone marrow and blood look like after moderate to marked bone marrow injury?
Bone marrow= increased fibrin (myelofibrosis) and low cellularity
An increased population of immature cells in the Bone Marrow of over 20% is indicative of what?
Atypical morphology of cells in the bone marrow population is indicative of what?
What can cause a dysplastic process in the bone marrow?
2. infectious agents
4. nutritional problems
5. myelodysplastic syndrome
what is the most common abnormality in maturation that causes myelodysplasia, and what does it result in?
asynchronous maturation of nucleus and cytoplasm. results in:
1. megaloblastic erythroid precursors
2. abnormally segmented neutrophils
3. dwarf megakaryocytes
What can cause primary myelodysplasia?
rapid production due to neoplasia
What can case secondary myelodysplasia?
rapid production due to overwhelming infection
What does the blood and bone marrow look like with myelodysplasia?
blood: cytopenia of one or more cell lines
bone marrow: hypercellular with low numbers of blast forms
when does irreversible necrosis of the bone marrow occur?
when damage is severe enough to effect the microcirculation leading to ischemia or destroying the hematopoeitic cell lines
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