Bone Marrow Flashcards
What are the indications for bone marrow collection?
Unexplained cytopenias Unexplained cytosis Marrow neoplasms (staging) Unexplained chemistry findings (hyperCa, hyperglobulinemia) FUO Marrow infection
What kind of patient requires or would benefit from bone marrow evaluation?
Unexplained cytopenias Unexplained cytosis Marrow neoplasms (staging) Unexplained chemistry findings (hyperCa, hyperglobulinemia) FUO Marrow infection
What are the sites of bone marrow collection in small animals? Which are preferred in skeletally immature animals?
Iliac crest, femur, *humerus (adult)
Skeletally immature: iliac crest, femur (NOT HUMERUS)
What is the difference between bone marrow aspirates and core biopsies. Are there certain indications or diseases in which one method is preferred?
Aspirates: Yields fragments of marrow that are smeared out and stained for cytologic evaluation
Core biopsies: Yields cylindrical section of intact marrow. LARGER needle, evaluated histologically, plus “rolled” impression cytology smear.
What instrumentation is needed for core biopsy or aspirate collection?
Aspriate: Illinois or Rosenthal needle
Core biopsy: Jamshidi needle
NEED CORE BIOPSY: After multiple “dry taps”, myelofibrosis, hypoplastic marrow, metaststic neoplasia
Be able to correctly identify and name in the correct progression, the cells of the erythroid and granulocyte lineages. What cells from these lineages are most numerous in marrow aspirates from
healthy animals?
Erythroid: Rubriblast Prorubricyte Rubricyte Metarubricyte Reticulocyte RBC
Neutrophil: Myeloblast Promyelocyte Neutrophilic myelocyte Nuetrophilic metamyelocyte Neutrophilic band Neutrophil
Monocyte:
Monoblast
Promonocyte
Monocyte
What is the marrow transit time for erythrocytes, granulocytes and platelets? How does peripheral demand (e.g., health vs. times of disease) influence this number?
Erythrocyte: 5 days
Granulocyte: 7 days
Platelets: 5 days
BM has stores that are ready to be release when demand increases
Why with bone marrow recovery do monocytes begin increasing in the blood before neutrophils?
Faster transit time (3 days vs. neutrophil 5 days)
What are considered normal findings in bone marrow aspirates taken from healthy dogs and cats?
Stainable iron present in dogs but NOT CATS
How many cells do we count when evaluating bone marrow aspirates? How is an M:E ratio generated?
Count 500 nucleated cells
Compare total nucleated myeloid cells to total nucleated erythroid cells
How do you interpret an M:E ratio? What additional information is need to make the M:E ratio “meaningful”?
Normally between 1:1 to 2:1
Need to know actual cell count #s and CBC to be able to interpret
If given a description of a bone marrow aspirate +/- CBC data, be able to determine which of the following are happening (erythroid hypoplasia, erythroid hyperplasia, myeloid hypoplasia, myeloid
hyperplasia, megakaryocytic hyperplasia, megakaryocytic hypoplasia)
.
Be able to correctly identify some differentials for the following findings: erythroid hypoplasia, erythroid hyperplasia, myeloid hyperplasia
Erythroid hypoplasia: inflammation, CKD, endocrinopathy, PRCA, FelV, myelopthisis, myelofibrosis
Erythroid hyperplasia: Hemolysis, blood loss, erythrocytosis, IMHA, MDS, iron deficiency, cobalamine deficiency
Myeloid hyperplasia: depletion, IMN, FeLV, Parvo/panleuk, drugs, Ab, Myelopthis, Meylofibrosis
Understand the concept of hypoplasia and effective and
ineffective hyperplasia.
Hypoplasia: not enough produced
Hyperplasia: lots produced. Appropriately = effective, inappropriately/due to disease = ineffective
Be familiar with causes of megakaryocytic hyperplasia and hypoplasia. Of the causes of hyperplasia, which are most common?
Hypoplasia:
Aelective is rare (ITP), usually with other cytopenias
Hyperplasia: **peripheral destruction or consumption Iron deficiency Inflammation Essential thrombocythemia Secondary to myeloid leukemia
What is general marrow hypoplasia/aplasia? Be familiar with some causes.
Generalized decrease in hematopoietic cells
Ddx: Drug induced (TMS, azothioprine) Estrogen toxicity Parvo/panleuk Chronic e. Canis Idiopathic/immune-mediated Myelophthisis Myelofibrosis
What is myelofibrosis?
What is myelophthisis?
Myelofibrosis: marrow filled with fibrous connective tissue
Myelophthisis: displacement of hematopoietic BM tissues
What is meant by the term leukemia? What is the difference between acute and chronic leukemias in
terms of diagnosis and laboratory findings (e.g. CBC and bone marrow data)? In terms of prognosis?
Neoplasms of BM-derived cells
Acute: MORE IMMATURE CELL TYPE, > 20% marrow blasts, often cytopenias, often circulating blasts, terrible prognosis (days to month)
Chronic: CELLS LOOK MORE MATURE, <20 % marrow blasts, cytosis, few or no circulating blasts, fair prognosis (1 + year)
Name a condition other than acute leukemia that could cause >20% blasts to be present in a marrow aspirate.
Other cause of BM injury (toxin)
These will not have circulating blasts
What diseases must chronic leukemias be differentiated from? Are there any cytologic features that may be present that can help?
Reactive “cytosis”
Look for evidence of dysplastic change
Bone marrow evaluation is the CORNERSTONE of diagnosing acute leukemias. However, for some of the chronic leukemias we discussed, bone marrow evaluation may not even help you make the
diagnosis? Why?
Need to rule out other causes of cytosis
What is different about chronic lymphocytic leukemia compared to all the other leukemias we discussed?
The only leukemia that may not arise from the bone marrow.
T-cll subset is through to arise from spleen with secondary marrow involvement
What is primary myelodysplastic syndrome? What are some differential diagnoses for dysplasia seen in the marrow? Do all forms of MDS have the same prognosis? MDS in some animals progresses to what other disease?
Abnormalities with early progenitor cells in the marrow +/- abnormalities in marrow micro-environment.
Characterized by hypercellular marrow with peripheral cytopenias, dysplastic features in > 10% of cells, and blast count lower than needed to diagnose acute leukemia.
Need to distinguish from secondary myelodysplastic syndromes
Not all have same prognosis
Some progress to acute leukemia
What is multiple myeloma? How is this diagnosis made? Be able to correctly identify plasma cells if
given a photomicrograph.
Plasma cell neoplasia
Dx made by 2/4 criteria:
- Monoclonal gammopathy
- Bence Jones proteinuria
- Presence of >20% plasma cells in BM
- Osteolytic bone lesions
