BoD Exam 1

hematopoiesis shift

yolk sac → liver and spleen → bone marrow

neutrophils

WBC w a short lifespan, often the 1st indicator of bone marrow issues.

Hematopoiesis

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

• BM will appear red if active

Extramedullary hematopoiesis (EMH)

The production of blood cells outside of the bone marrow, primarily in the spleen.

Myelofibrosis

The fibrosis/scarring of the bone marrow, leading to peripheral cytopenias and decreased production of blood cells.

Regenerative anemia

caused by hemorrhage or hemolysis

leading to erythroid hyperplasia

Non-regenerative anemia

caused by infection, toxins, mediations, estrogens, CKD, Fe deficiency or cancer

resulting in a erythroid hypoplasia or aplasia

Gelatinous transformation

replacement of bone marrow adipose tissue with mucinous material, seen in cases of emaciation or starvation.

Aplastic anemia

Anemia affecting all cell lines, characterized by necrosis of the bone marrow and a decreased ability to produce blood cells.

Equine infectious anemia

An infectious disease that can cause immune-mediated thrombocytopenia.

Ehrlichiosis

An infectious disease that can cause immune-mediated thrombocytopenia and non-neoplastic lymphocytosis in dogs and cats.

Acute leukemia

characterized by poorly differentiated cells, aggressive clinical course, and high blast cell count (>20%) in the bone marrow or blood.

Homogenous expansion

associated w a neoplastic process

Heterogenous expansion

associated w a reactive process

Multiple myeloma

cancer that affects plasma cells in the bone marrow

Trend Fat:Hematopoietic cells in BM

fat increases w age, while hematopoietic cells decrease

w age, BM goes from red/active → yellow/fatty/inactive

1:1

myeloid:erythroid in nx BM

CBC

essential for diagnosis of hematologic disturbances

areas where hematopoietic marrow is concentrated in adults

spine, pelvis, sternum, ribs, calvarium and proximal end of limb bones 

horses

do not release retics into circulation

• cant use retics to determine if regen or nonregen anemia

dog

spp that have apparent central areas of pallor

• can be used to determine RBC damage

spp order of longest to shortest mean RBC lifespan

horses & cattle → dogs → cats

mechanism for myelofibrosis

scar formation after necrosis

high concentration of growth factors w marrow injury or activation

idiopathic

causes of bone marrow necrosis leading to myelofibrosis

leukemias

infiltrative metastatic neoplasia

BVDV, E. canis, FeLV

sepsis

drugs or toxins

irradation

chronic hemolytic anemia

main lesion of serous atrophy of fat

gelatinous transformation

clinical abnormalities seen w regenerative anemia caused by hemorrhage

iron deficiency (w chronicity)

decreased protein concentration

increased BUN relative to creatinine if there’s a GI bleed

clinical abnormalities seen w regenerative anemia caused by hemolytic anemia

icterus

hyperbilirubinemia

hemoglobinuria

splenomegaly

clinical abnormalities seen w nonregenerative anemia w pure red cell aplasia

pale mm

hypoxic

weak, exercise intolerance

tachycardia, murmurs

+/- lymphocytosis, plasmacytosis, thrombocytosis, myeloid hyperplasia 

clinical abnormalities seen w nonregenerative anemia w aplastic anemia

Pale mm 

Hypoxic 

Weak, exercise intolerance 

Tachycardia, murmurs (bc decreased blood viscosity) 

Secondary infxns 

• Neutropenia (1wk post insult) 

Hemorrhages  

• Thrombocytopenia (2 wk post insult)

causes of aplastic anemia in dogs and cats

antimicrobial agents

chemotherapeutic agents

estrogen

phenylbutazone

aflatoxin B

ehrlichia

parvo

FeLV/FIV

causes of aplastic anemia in cattle and sheep

bracken fern

trichloroethylene

aflatoxin B

causes of aplastic anemia in horses

aflatoxin B

EIA

causes of non-neoplastic lymphocytosis in dogs and cats

age/antigenic stimulation

epinephrine

chronic inflammation

E canis infxn

hypoadrenocorticism

paraneoplastic lymphocytosis

hyperthyroidism

CD34 expression on flow

acute leukemia

>20%

amount of blast cells in blood or BM for acute leukemia

necropsy findings of acute leukemia

pale mm

BM highly cellular but pancytopenia

splenomegaly

LN involvement

can infiltrate many organs

CD21 expression on flow cytometry

CLL/SLL (B cell chronic lymphocytic leukemia/small cell lymphocytic lymphoma) 

>5000

neoplastic cells/uL in peripheral blood for diagnosis of chronic leukemia

clinical abnormalities for chronic leukemia

Often incidental lymphocytosis 

Anemia not uncommon (usually mild) 

Other cytopenias usually NOT present 

May be well differentiated cells (look like mature cells) 

CD4 (T cell)

most common chronic leukemia phenotype in cats

chronic leukemia necropsy findings

splenomegaly

anemia

lymphadenopathy

highly cellular BM

boxers

breed associated w worse prognosis w B cell chronic lymphocytic leukemia

benefits of using flow in cases of lymphocytosis in dogs and cats

large # of Ags can be evaluated

distinguishes homogenous from heterogenous expansions

identifies aberrant Ag expression

objective measure of size

provides prognositic info

clinical abnormalities that can be seen w multiple myeloma

hyperglobulinemia

hypercalcemia

pancytopenia

clinical abnormalities of EIA (equine infectious anemia)

Fever, depression, LN enlargement, splenic congestion

hemolytic crisis: pale w mucosal hemorrhage and dependent edema

Icterus

Splenomegaly

clinical abnormalities of BVDV

thrombocytopenic hemorrhagic syndrome

• severely thrombocytopenic and neutropenic w multisystemic hemorrhages

canine distemper virus

causes atrophy and necrosis of bone lining and BM cells

feline leukemia virus (FeLV)

disrupts nx hematopoiesis by inducing genetic mutations, infecting hematopoietic cells

viral diseases in dogs and cats that can affect the thymus

parvovirus

canine distemper virus

feline immunodeficiency

viral diseases that affect the thymus in horses, cattle, and pigs

equine herpes virus -1

bovine viral diarrhea virus

porcine circovirus-2

postweaning multisystemic wasting syndrome

caused by porcine circovirus-2

affect of porcine circovirus-2 on LNs

enlarged, Lymphoid depletion of follicles and paracortex → replacement by granulomatous inflammation 

affect of porcine circovirus-2 on thymus

(atrophy) to granulomatous inflammation w multinucleated cells w cytoplasmic viral inclusions

bovine viral diarrhea virus

causes thymic atrophy in cattle

epithelial cells

neoplastic cell of a thymoma

paraneoplastic syndromes that can be seen w a thymoma

myasthenia gravis and megaesophagus

lymphocytosis

exfoliative dermatitis

differentials for a cranial mediastinal mass

neuroendocrine tumor

lymphoma

hemagiosarcoma

thymoma

virus

only associated w lymphoma in cats, no other spp

younger animals

typical age associated w lymphoma, except for dogs

non-neoplastic causes of diffuse, SOFT enlargement of the spleen

gastric volvulus w splenic entrapment

splenic volvulus/torsion

barbiturate euthanasia, anesthesia, or sedation

acute hyperemia (septicemia)

acute hemolytic anemia

congestion

diffuse, soft enlargement of the spleen occurs w

anthrax

primary dz of cattle and sheep

sequence of events causing anthrax

Spores are ingested, replicate in the GI tract, spread to LNs 

Disseminate through bloodstream causing septicemia → congestion 

Intravascular free bacilli

can be seen on impression smears of the spleen or blood in anthrax

causes of diffuse, FIRM enlargement of the spleen

chronic hemolytic anemia

diffuse granulomatous disease

neoplasia

extramedullary hematopoiesis

storage dz or amyloidosis

infiltrative dz

splenomegaly w FIRM consistency is due to

differentials for SOFT/bloody nodules in the spleen

hematomas

incomplete contraction

hemorrhagic infarction

hemangiosarcoma

differentials for FIRM nodules in the spleen

lymphoid and complex nodular hyperplasia

granulomas or abscesses

primary or metastatic neoplasia

extramedullary hematopoiesis

endothelial cell

neoplastic cell of hemangiosarcomas

golden retrievers, german shepherds, and labs

breeds commonly affected by hemangiosarcoma

spleen, heart (right auricle) and liver

most common primary sites of hemangiosarcoma

quick hemorrhage

cause of (lack of) clinical signs in hemangiosarcoma

bacterial causes of granulomatous disease in the spleen

Mycobacteriosis 

Tularemia 

Yersiniosis 

Brucellosis 

fungal causes of granulomatous disease in the spleen

Blastomycosis 

Histoplasmosis 

Coccidiodosis 

Sporotrichosis  

protozoal cause of granulomatous disease in the spleen

Toxoplasmosis 

Neosporosis 

viral cause of granulomatous disease in the spleen

FIP

pyogenic bacteria that cause abscesses or pyogranulomas in the spleen

Streptococcus 

Rhodococcus 

Trueperella 

Corynebacterium  

Bernese Mountain Dog, Golden Retrievers, Rottweilers, flat-coated retrievers 

breeds commonly affected by histiocytic sarcoma

macrophages of spleen and bone marrow

cell of origin of hemophagocytic histiocytic sarcoma

siderotic plaques

Rough, brown to yellow plaques along the serosal surface 

Histo see mineralization and pigment from heme breakdown 

Paracortex of LN

Mainly T cells and fewer macs and DCs 

Medulla of LN

macrophages (CD204), lymphs and plasma cells  

Cortex of LN

B cells

Yorkshire Terriers and Norwegian Lundehund

breeds commonly associated w enteric lymphangiectasia

white spots

corresponds to villous expansion by lacteal dilation in enteric lymphangiestasia

enteric lymphangiestasia

most common cause of PLE

clinical abnormalities seen w PLE & lymphangiectasia

hypoproteinemia, hypocholesterolemia, lymphopenia, hypocalcemia 

• Peripheral edema, ascites, hydrothorax

Serosal/mural lesions: Accumulations of granulomatous inflammation forming white masses 

lesions in lymphangitis as it responds to fat and chyle

Intestinal lipogranulomatous lymphangitis 

Inflammatory foreign body rxn to lipid-rich chyle 

No PLE at presentation 

causes of chylothorax

idiopathic

trauma

congestive heart failure

chest tumors

viruses that can injure lymphoid tissue

parvovirus

canine distemper virus

feline immunodeficiency virus

equine herpes virus-1

bovine viral disease virus

spread of plague

eating infected animals or bite by an infected flea

gross findings in cats w plague

fever, loss of app, lethargy, enlarged LNs

causes of bacterial lymphadenitis in horses

Streptococcus equi ssp. Equi (Strangles) 

Rhodococcus Equi 

Johne’s Dz

caused by Mycobacterium avium paratuberculosis 

Bovine Tuberculosis

Mycobacterium bovis 

Caseous lymphadenitis 

caused by Corynebacterium pseudotuberculosis 

gross findings in Johne’s dz

Chronic wasting, proliferative enteritis 

Enteritis and granulomatous lymphadenitis  

gross findings in Bovine Tuberculosis

LNs are necrotic and suppurative/ abscessed 

gross findings in caseous lymphadenitis

Purulent to inspissated w concentric laminations 

Can cause internal abscessation and chronic wasting