Lecture 5 Part 1

Question 1

How would you expect the bone marrow to respond to anemia?

Thrombocytopenia?

Leukopenia?

Answer 1

Erythroid hyperplasia

Megakaryocytic hyperplasia

Myeloid hyperplasia

Question 2

Describe the maturation of platelets

Answer 2

Progenitor stem cells -> megakaryoblast -> promegakaryocyte -> megakaryocyte -> millions of platelets

• undergo endomitosis (replicating without dividing)

Question 3

Describe the maturation of a RBC

Answer 3

Proliferative:
Rubriblast -> prorubricytes -> rubricytes ->

Maturation only:

Rubricytes -> metarubricytes -> reticulocytes -> erythrocytes

Question 4

Describe myeloid/ granulocytic maturation

Answer 4

Proliferation:
Myeloblast -> promyelocytes -> myelocytes

Maturation only:
Myelocytes -> metamyelocytes -> bands -> neutrophils

Question 5

Why might you look for marrow disease?

Answer 5

Unexplained nonregenerative anemia
Unexplained cytopenias
Abnormal cells in circulation
Unexplained increases in cells
Monoclonal gammothapy
Staging cancers
Unexplained hypercalcemia
To evaluate iron stores
Look for infectious disease

Question 6

Unexplained cytopenias- tell me about them

Answer 6

May be selective for one cell line or involve all three

EXCLUDING lymphocytes and monocytes

May be hypocellular with inadequate proliferation or hypercellular with inadequate function

Question 7

What are you looking for when looking for abnormal cells in circulation?

Answer 7

Persistent thrombocytosis
Persistent leukocytosis
Marked neutrophilic left shift without evidence of inflammation
NRBCs without polychromasia
Blast cells or unidentified cells present

Question 8

What might hyperproteinemia indicate?

Answer 8

Multiple myeloma
Lymphoid neoplasia
Leishmaniasis
Systemic fungal disease like histoplasmosis

Question 9

What infectious agents might you look for in the marrow?

Answer 9

Cytauxzoon schizonts
Leishmaniasis
Systemic or local fungal infection

Question 10

What might hypercalcemia indicate?

Answer 10

Lymphoid neoplasms
Multiple myeloma
Metastatic neoplasms

Question 11

What types of metastasis might you find when checking bone marrow

Answer 11

Lymphoma
Mast cell tumor
Carcinomas or sarcomas

Question 12

What is M:E

Answer 12

Myeloid to erythroid ratio

If low, means you have more erythrocytes
If high, means you have more myelocytes

NEED pcv and neutrophil count to interpret

Question 13

When might the M:E ratio be of little value?

Answer 13

If the marrow is hypoplastic or filled with neoplastic cells

Question 14

low M:E, normal PCV

Low M:E, normal neutrophil count

Answer 14

Changes reflect issues in neutrophilic series

Changes reflect issues in erythrocytes

Question 15

When is M:E difficult to interpret?

Answer 15

If PCV and neutrophils are abnormal

Question 16

Tell me about acute reversible bone marrow injuries

Answer 16

Usually transient
Neutropenia usually occurs
If injury is longer than 1-2 weeks, thrombocytopenia and nonregenerative anemia are possible
Marrow should recover if no other complications are present
During recovery, marrow may become hypercellular

Question 17

Causes of reversible marrow disease

Answer 17

Infection
Drugs/ chemicals- estrogen in dogs and ferrets, phenylbutazone, albendazole, TMS, methimazole
Chemotherapy
Idiopathic, immune mediated (Central IMHA)

Question 18

Tell me about irreversible marrow injuries (chronic)

Answer 18

Due to a defect in hematopoiesis

Does not spontaneously improve

Question 19

Causes of irreversible marrow injury

Answer 19

Myelopthisis (replacement of marrow with other cells or abnormal tissue)

Myelodysplasia (FeLV)

Radiation

Chronic exposure to benzene related chemicals (rare in animals)

Question 20

Myelofibrosis

Answer 20

Replacement of bone marrow with fibrin

Occurs due to several types of marrow injuries (damage to marrow, necrosis, fibrosis)

Hemolytic anemias (central IMHA)

Associated with abnormal growth of hematopoietic cells and metastasis

Radiation

Idipathic causes