Exam 3 - Polycythemia, Splenic Disorders, & Lymphadenopathies

Question 1

what is relative polycythemia?

Answer 1

artificial increase in Hct but a normal RBC count – increase in Hct from loss of plasma volume

seen with dehydration & exudative wounds (burns), may seen increased Na, TS, & pre-renal azotemia

Question 2

what is absolute polycythemia?

Answer 2

true increase in Hct/PCV – classified as primary or secondary

Question 3

what values define polycythemia in dogs? cats?

Answer 3

dogs – PCV >55%, hemoglobin > 18 g/dL

cats - >50%, hemoglobin > 14 g/dL

Question 4

how is primary polycythemia defined?

Answer 4

bone marrow is producing too much – NOT driven by EPO

Question 5

how is secondary polycythemia defined?

Answer 5

driven by increased EPO – either appropriate or inappropriate

Question 6

what are the end target organs in polycythemia & how are they affected?

Answer 6

CNS – ataxia, mentation changes, & seizures

ocular - +/- retinal hemorrhage, retinal detachment, blindness

nasal – epistaxis

Question 7

what does ‘sludgy’ blood indicate?

Answer 7

hyperviscosity

Question 8

what clinical signs are associated with polycythemia?

Answer 8

sludgy blood, hypercoagulability, PU/PD, & caudal cyanosis (right to left shunt)

Question 9

what is the purpose of phlebotomy in patients with polycythemia?

Answer 9

removing a certain % of blood volume to decrease hyperviscosity

Question 10

what is the target PCVs when performing a phlebotomy?

Answer 10

dogs – 55%
cats – 50%

goal is to remove 10-20 ml/kg

Question 11

T/F: phlebotomy may not be ideal for all cases, but it should be performed in patients exhibiting clinical signs of polycythemia

Answer 11

true

Question 12

what is the mechanism of primary absolute polycythemia?

Answer 12

marrow is producing too much erythrocyte lineage

peripheral EPO levels are low

bone marrow shows same as if EPO levels are high

can’t use bone marrow to differentiate primary from secondary

Question 13

T/F: bone marrow examination can be used to differentiate primary from secondary polycythemia

Answer 13

false - not ideal

Question 14

what is the mechanism of appropriate secondary polycythemia?

Answer 14

primary trigger – body needs more PaO2 (hypoxemia), such as pulmonary disease, increased altitude, or right to left cardiac shunting

Question 15

T/F: for appropriate secondary polycythemia, the most important therapy long-term is phlebotomy

Answer 15

false – find the underlying cause & treat that

Question 16

what is the mechanism of inappropriate secondary polycythemia?

Answer 16

secondary source of EPO being produced independent of O2 need – normal PaO2 – diseases such as renal EPO producing tumor, or rare other tumors such as nasal

Question 17

how is secondary inappropriate polycythemia treated?

Answer 17

must find mass & if possible, & remove

Question 18

what diagnostics are typically used for polycythemia?

Answer 18

thoracic & abdominal imaging – tumor hunt!!!

history/clinical signs are very important!!!

PaO2 levels, history of respiratory or cardiac disease

EPO levels are ideal – but very hard to do & often unavailable

Question 19

what is the therapy used for polycythemia?

Answer 19

find the underlying cause!!!!

phlebotomize as necessary & pharmacologic management

Question 20

what is the mechanism of action of hydroxyurea for patients with polycythemia?

Answer 20

erythropoiesis suppressant

Question 21

why is clopidogrel used for patients with polycythemia?

Answer 21

anti-coagulant

Question 22

what are the 3 general functions of the spleen?

Answer 22

1. immune system – main defense against intracellular & cell surface pathogens affecting RBC/WBC, cleans up expired RBC
2. reservoir – platelets, lymphocytes, & RBCs, extramedullary hematopoiesis
3. iron metabolism

Question 23

what happens with splenic contraction?

Answer 23

increases RBC – can see with bone marrow failure, anemia, & contraction can increase PCV substantially

Question 24

why is the spleen important for iron metabolism?

Answer 24

storage, metabolism, & delivery of iron to the bone marrow

splenectomized patients have low iron – but other cells eventually take over this process

Question 25

what specific organisms do we care about in relation to the spleen?

Answer 25

babesia, mycoplasma, & rickettsial bugs

Question 26

what 4 non-neoplastic splenic diseases are covered?

Answer 26

1. splenomegaly – not always pathologic, can see with sedation 2. infectious – fungal, exfoliates well 3. hypersplenism – rare benign disorder 4. splenic torsion in dogs – surgical emergency, more common in deep chested breeds

Question 27

what is the most common non-neoplastic splenic disease?

Answer 27

splenomegaly

Question 28

what is the most common neoplastic splenic disorder?

Answer 28

hemangiosarcoma - often cavitated, aspiration not high yield

Question 29

what are the most common locations of hemangiosarcoma tumors?

Answer 29

right atrium, liver, & spleen

Question 30

how is hemangiosarcoma treated?

Answer 30

recommended splenectomy

Question 31

what is hypersplenism?

Answer 31

rare, benign disorder sequestration of RBC (associated with increased RBC turnover) no medical management

Question 32

what is the classic appearance of splenic lymphoma?

Answer 32

chicken wire or leopard spot appearance

Question 33

how is lymphoma of the spleen diagnosed?

Answer 33

FNA of liver or spleen is typically high yield

Question 34

how are mast cell tumors of the spleen diagnosed?

Answer 34

FNA of liver or spleen is typically high yield

Question 35

what dog breeds are predisposed to histiocytic sarcomas?

Answer 35

bernese mountain dogs & flat coated retrievers

Question 36

what are some contraindications to splenic aspiration?

Answer 36

suspect hemangiosarcoma/hemangioma thrombocytopenia < 60,000 or coagulopathy suspected

Question 37

what 4 diseases are covered for neoplastic splenic disorders?

Answer 37

1. hemangiosarcoma 2. lymphoma 3. mast cell tumor 4. histiocytic sarcoma

Question 38

what are some clinical signs associated with splenic disease?

Answer 38

if severe – collapse, anorexia, fluid wave, vomiting, pale MM, hemoabdomen

Question 39

what is the usual cause of a hemoabdomen?

Answer 39

ruptured splenic or hepatic mass

Question 40

how is hemoabdomen diagnosed?

Answer 40

abdominocentesis/pericardiocentesis

Question 41

blood that has pooled in the abdominal cavity or around the pericardium should NOT clot because the clotting factors are used up. what does it mean if you have blood clots?

Answer 41

active bleeding present or you hit an organ – liver, spleen, or heart

Question 42

what is the minimum database for splenic disease?

Answer 42

CBC - +/- anemia, thrombocytopenia due to sequestration chemistry – WNL or increased globulins

Question 43

what may be seen on ultrasound on an animal with splenic disease?

Answer 43

splenomegaly, mottled or abnormal echotexture, masses, or splenic lymphadenopathy

Question 44

what may be seen on radiographs on an animal with splenic disease?

Answer 44

metastasis, heart base mass

Question 45

what is the premise of NuQ testing for splenic disease?

Answer 45

screens for increased amounts of DNA nucleosomes – NuQ increased a lot with malignancy good chance between differentiating between benign vs. malignant splenic masses & lymphoma

Question 46

when would you run a NuQ test?

Answer 46

screen breeds at risk, splenic mass prior to surgery if the owner is on the fence

Question 47

what is the therapy for hypersplenism & splenic torsion?

Answer 47

surgery

Question 48

what is the therapy for splenic neoplasia?

Answer 48

remove mass ideally – if infiltrated other organs, may need to FNA to look for disseminated disease - lymphoma, MCT, & histiocytic sarcoma

Question 49

if EMHA or infectious splenic disease is present, how do you diagnose it? what about therapy?

Answer 49

diagnose via FNA, EIA< or serology IMHA cases – treat IMHA some refractory cases require splenectomy

Question 50

T/F: you can’t differentiate between benign & malignant neoplasia of the spleen using ultrasound alone

Answer 50

true - must do histopath

Question 51

what are the etiologies of reactive/benign lymphadenopathy & malignant lymphadenopathy?

Answer 51

1. reactive/benign – anything antigenic to the immune system, infectious diseases causing a reactive lymphadenopathy or infection in the lymph node 2. malignancies – primary neoplasia such as lymphoma or mast cell tumor, or metastasis

Question 52

hilar lymphadenopathy is often indicative of what?

Answer 52

very indicative of fungal disease

Question 53

what should you do if there is sternal lymphadenopathy?

Answer 53

sternal lymph nodes drain the abdomen – so only if it’s enlarged, look at the abdomen

Question 54

if you see sub lumbar lymphadenopathy, what is this often indicative of?

Answer 54

prostatic disease or neoplasia

Question 55

how can you differentiate between reactive & neoplastic lymph nodes on FNAs?

Answer 55

normal lymph node has mostly small lymphocytes neoplastic nodes – look for mitotic figures & other criteria or malignancy

Question 56

FNAs of neoplastic nodes can be diagnostic for what round cell tumor types?

Answer 56

lymphoma, nasal adenocarcinoma, melanoma, & mast cell tumor

Question 57

what are the criteria of malignancy for FNAs of lymph nodes?

Answer 57

1. anisocytosis 2. anisokaryosis 3. mitotic figures 4. increased N:C ratio 5. vacuolization 6. multinucleated cells

Question 58

what 2 atypical agents cause disease in dogs & cats causing large, sometimes hemorrhagic & purulent discharge from lymph nodes that is zoonotic & requires a biopsy to diagnose?

Answer 58

mycobacterium & cornyebacterium tuberculosis

Question 59

why use flow cytometry for lymph node aspirates?

Answer 59

differentiate between reactive & neoplastic nodes – ship immediately!!!

Question 60

T/F: lymphoma is often very easy to diagnose if lymphadenopathy is present

Answer 60

true

Question 61

T/F: NuQ vet cancer test is helpful in screening at risk breeds for lymphoma

Answer 61

true

Question 62

T/F: certain atypical bacterial infections can cause marked lymphadenopathy, and may require certain precautions & biopsy

Answer 62

true

Question 63

where should you palpate in an animal with lymphadenopathy? why?

Answer 63

axillary & sub-inguinal are abnormal to be able to palpate!!!! lymphadenopathy is non-specific but gives you clues