Diseases of the Bone Marrow

Question 1

where does extramedullary hematopoiesis primarily occur in an adult animal?

Answer 1

spleen

Question 2

bone marrow produces cells based on _________ need

Answer 2

peripheral

Question 3

how does hematopoiesis distribution change?

Answer 3

changes with age from active red tissue to inactive fatty tissue. in an adult animal, there is much more adipose tissue and thus is much less active than in a young animal

Question 4

dogs have a very large storage pool of __________

Answer 4

neutrophils

Question 5

in cats, there are threefold more ________ _______ relative to circulating neutrophils

Answer 5

marginal neutrophils: they are stuck to the vessels and thus you don’t see them when you draw blood

Question 6

what neutrophil population is being counted when doing BW?

Answer 6

circulating pool of neutrophils

Question 7

in normal bone marrow, the myeloid to erythroid ratio is

Answer 7

1:1
fat to hematopoietic cell ratio increases as the patient ages

Question 8

what diagnostic is essential for diagnosis of hematologic disturbances?

Answer 8

CBC

Question 9

what are causes of myelofibrosis? (Primarily necrosis)

Answer 9

• neoplasia: leukemias, infiltrative metastatic dz
• infectious disease: FeLV (chronic stimulation), sepsis
• toxins: carprofen, chemo, estrogen, phenobarb, heavy metals, irradiation
• chronic hemolytic anemia

Question 9

what is hematopoiesis?

Answer 9

lipolysis + myeloid (bone marrow) expansion in residual red (hematopoietic) marrow

Question 10

you want to send a sample of bone marrow to the lab for interpretation what information (besides signalment) should you absolutely include with this sample?

Answer 10

CBC data

Question 11

myelofibrosis is an example of what type of bone marrow disease?

Answer 11

degeneration: see very little adipose sites, fibrosis, macrophages hanging onto iron pigment

Question 12

what are the mechanisms of myelofibrosis?

Answer 12

• scar formation after necrosis
• high concentration of growth factors with marrow injury or activation
• idiopathic
• can result in cytopenia: because now there isn’t a nice foundation for cells to grow

Question 13

what gross feature will you see in the bone marrow of an emaciated patient?

Answer 13

serous atrophy of fat- gelatinous transformtion

Question 14

A goat presents for postmortem exam. The goat was found in the bed of a truck with a leash. The owner had been warned the goat needed access to food and water and this was inappropriate housing. On exam, there are no fat stores (subcutaneous or visceral). When you look at the bone marrow, the tissue is pale and gelatinous with slight translucency. What do you expect for the histopathology report of the bone marrow?

Answer 14

Decreased cell lines and adipose and replacement by mucinous matrix

Question 15

what cytopenias can be present with bone marrow hypoplasia/aplasia

Answer 15

• anemia: regen or non-regen (most common)
• thrombocytopenia : immune-mediated, hemorrhage, DIC
• neutropenia: immune, tissue demand (depends on storage pool)
• lymphopenia: common in sick animals, loss of lymphocyte rich fluid

Question 16

in order for hematopoiesis to occur, what components need to be present?

Answer 16

stimulus/growth factors
ex for erythropoiesis, there needs to be erythropoietin from the kidney
lymphopoiesis: needs IL4 for B cells, IL2, NK, for T cells

Question 17

your patient presents with anemia. what are some basic causes of anemia?

Answer 17

• Increased destruction or lysis
• Increased loss/hemorrhage
• Decreased red blood cell production

Question 18

of the causes of anemia, what are causes of regenerative anemia?

Answer 18

• hemorrhage or hemolysis
  causes erythroid hyperplasia in the bone marrow

Question 19

of the causes of anemia, what are causes of non-regenerative anemia?

Answer 19

• Bone marrow insult (many causes)
• Erythroid hypoplasia or aplasia in the bone marrow

Question 20

what are clinical abnormalities seen with regenerative anemia caused by hemorrhage?

Answer 20

• with chronicity, can have iron deficiency anemia, leads to problems producing RBC
• decreased plasma or serum protein concentration - increased urea nitrogen relative to creatinine

Question 21

what are clinical abnormalities seen with regenerative anemia caused by hemolytic anemia?

Answer 21

• icterus
• hyperbilirubinemia
• hemoglobinuria
• splenomegaly
• bone marrow response

Question 22

what are causes of non-regenerative anemia?

Answer 22

• infectious
• toxins
• medications
• estrogens
• CKD (Decreased erythropoietin)
• iron deficiency (anemia of inflammatory disease)
• cancer

Question 23

what is pure red cell aplasia? what are the 2 types?

Answer 23

1. absence of erythropoiesis and severe non-regenerative anemia
   primary: destruction of early erythroid progenitor cells
   secondary: admin of rhEPO, parvo, FeLV subgroup C
2. bone marrow: absence of erythroid precursors, +/- lymphocytosis, thrombocytosis, myelofibrosis

Question 24

What clinical and/or gross findings might you expect with non-regenerative anemia in opposition to hemolytic anemia?

Answer 24

instead of icterus, see pale mm because there aren't a lot of RBC circulating

Question 25

what are the clinical/pathologic findings expected with regenerative anemia?

Answer 25

reticulocytes, pale mm, splenomegaly

Question 26

what are the expected bone marrow findings of regenerative anemia?

Answer 26

active: erythroid hyperplasia

Question 27

what are the clinical/pathologic findings expected with non-regenerative anemia?

Answer 27

palor, myelofibrosis

Question 28

what are the expected bone marrow findings with non-regenerative anemia?

Answer 28

absence of erythroid precursors

Question 29

Which of the following is a cause of non-regenerative anemia * A. Blood loss * B. Chronic GI bleed * C. Estrogen administration * D. Immune-mediated hemolysis

Answer 29

C. estrogen administration all other choices can cause regenerative anemia

Question 30

aplastic anemia is a decrease in what cell lines?

Answer 30

red AND white blood cells!! not just RBC lines!!

Question 31

what are causes of aplastic anemia in dogs and cats?

Answer 31

- abx, chemo agents - estrogen in dogs ** - parvo ** - FeLV/FIV ** - EIA in horses **

Question 32

what are causes of aplastic anemia in cattle and sheep?

Answer 32

bracken fern, trichloroethylene

Question 33

what clinical signs do you expect with aplastic anemia?

Answer 33

petechiae, hemorrhages, secondary infections

Question 34

how does parvo virus cause aplastic anemia?

Answer 34

- parvo and feline panleuk - virus has tropism for mitotically active cells - oronasal entry to tonsils and peyer's patches - lymphatic spread to thymus, spleen, lymph nodes - virally induced lymphopenia - PANLEUKOPENIA: lymphocytolysis in lymphoid tissue and destruction of hematopoietic precursors in the bone marrow

Question 34

what "penias" do you expect to see with aplastic anemia?

Answer 34

- neutropenia: they circulate 5-10 hours, develops within a week post-insult - thrombocytopenia: platelets circulate 5-10 days. develops the second week after insult

Question 34

what can cause an erythrocytosis?

Answer 34

- dehydration: hemoconcentration - epinephrine: mediated splenic contraction - epo-mediated erythroid hyperplasia - erythroid neoplasia: uncommon*, diagnosis of exclusion

Question 34

you see a dog that had been recently given estrogen. knowing your CSU education, you remember that you likely will start to see aplastic anemia in this patient, consisting of both neutropenia and thrombocytopenia. of those 2, which are you expecting to see first appear? why?

Answer 34

see neutropenia first: develops within 1 week after the insult see thrombocytopenia second, as it develops the second week after insult

Question 34

how long do neutrophils circulate? what about platelets?

Answer 34

neutrophils: circulate 5-10 hours platelets: 5-10 DAYSSSSS

Question 34

T/F: parvovirus, FeLV/FIV, and EIA all cause aplastic anemia

Answer 34

true

Question 34

what causes immune-mediated neutropenia?

Answer 34

- immune destruction of neutrophils or their precursor: causes similar to other immune-mediated cytopenias - bone marrow: granulocytic hypoplasia or hyperplasia, lymphocytosis - diagnosis of exclusion and response to immunosuppressive therapy

Question 35

what causes immune-mediated thrombocytopenia?

Answer 35

- IDIOPATHIC >>>>> - infectious diseases: EIA, ehrlichiosis - drug induced: cephalosporins, sulfonamides - neoplasia - other immune disease

Question 35

what growth factors need to be present for erythropoiesis?

Answer 35

erythropoietin! kidneys

Question 36

What is the primary difference between regenerative and non- regenerative anemia?

Answer 36

The presence or absence of bone marrow response