Polycythemia/Leukemia

Question 1

What is polycythemia?

Answer 1

Increased red cell concentration

Question 2

What are examples of relative polycythemia?

Answer 2

Hemoconcentration

• Dehydrationg
• Fluid shifts - hemorrhagic colitis; not systemically dehydrated

Redistribution of red cells chillin in the spleen

• excitement
• exercise - horses off the track

Question 3

What are examples of absolute polycythemia?

Answer 3

Increased erythropoietin

• Appropriate - chronic hypoxia (measure 02a)
• Inapproproate EPO secretion (renal cysts, tumors) - cells that make EPO are hypoxic and assume the rest of the body is too.

Primary - Polycythemia vera (myeloproliferative disorder)

Question 4

A 4 year old dog presents for lethargy and vomiting. PCV is high at 75% and protein is high at 9.8 (6-8). What is a probable cause for the polycythemia?

Answer 4

Dehydration due to vomiting (relative)

Question 5

What is the most likely cause of increased albumin levels?

Answer 5

Dehydration

Question 6

A 4 year old dog with BUN 145 (7-28), Creat 6.5 (0.9-1.7), and Phos 12.2 (2.8-6.1) has a urine SG of 1.011, indicating that glomerular filtration is normal. The urine sediment shows RBCs and 6-sided crystals. What is the likely cause of the high renal values?

Answer 6

Ethylene glycol poisoning

Calcium oxalate crystals are seen in antifreeze poisoning. Metabolites damage renal tubular epithelial cells, which explains the renal values on the chemistry. Increased calcium levels lead to formation of the crystals.

Question 7

A dog presents for lethargy and PU/PD. The PCV is 69% and protein is normal. Arterial O2 is normal, but the erythropoietin level is increased. What is the likely cause of increased PCV?

Answer 7

Kidney mass or cyst.

*Absolute polycythemia with inappropriate EPO secretion

Question 8

A 9 year old dog presents for lethargy and PU/PD. She has a PCV of 71% and the protein level is normal. You test arterial O2 and erythropoietin and both are normal. A blood film shows normal looking erythrocytes with normal maturation. What is the likely cause of the increased PCV?

Answer 8

Polycythemia vera

Question 9

A 7 year old dog with heart disease presents for lethargy and dyspnea. He has a PCV of 62% and normal protein level. Reticulocyte count is increased at 100 (0-60). Arterial O2 is decreased and erythropoietin is increased. What is the cause of the polycythemia in this dog?

Answer 9

Chronic hypoxia

*Absolute polycythemia with appropriate EPO secretion

Question 10

What is difficult about diagnosing stage 5 lymphomas?

Answer 10

Stage 5 lymphomas are leukemic, which makes them hard to distinguish from a leukemia

Question 11

Blood tests on a cat show marked neutrophilia and normal maturation. How can neutrophilia from inflammation be distinguished from neutrophilia due to a chronic myeloproliferative disease?

Answer 11

If neutrophil counts are greater than 100,000/uL it’s a chronic myeloproliferative disease.

Question 12

What number of lymphocytes indicates a lymphocytic leukemia in any species?

Answer 12

Greater than 35,000/uL

Question 13

What is the most reliable way to identify cell types in order to classify lymphoid vs myeloid proliferations?

Answer 13

Monoclonal antibody binding to antigens

Question 14

What test is used to identify a clonal, neoplastic population of cells, and differentiates non-neoplastic lymphoproliferative disorders?

Answer 14

PCR (PARR)

Question 15

A blood film on a dog shows numerous lymphoblasts. What is the prognosis?

Answer 15

Poor.

This is acute lymphoblastic leukemia. MST is 9 days for both ALL and AML.

Question 16

A blood smear on a dog shows numerous mature, well differentiated neutrophils. The neutrophil count is over 100,000/uL, so you know this isn’t just an infammatory response. What is the prognosis?

Answer 16

Not so bad. Dogs with chronic leukemias can live for years.

Question 17

B or T cell neoplasias involving the bone marrow or blood are called:

Answer 17

lymphocytic leukemias

Question 18

B or T cell neoplasias that are confined to solid tissue are known as:

Answer 18

Lymphomas

Question 19

What are 2 important features of lymphocytosis that can help differentiate the process?

Answer 19

Magnitude and morphology

Question 20

Although antigenic stimulation is a rare cause of lymphocytosis in small animals, what is an exception?

Answer 20

Canine Ehrlichiosis

*Large granular lymphocytes and polyclonal gammopathy will likely be present in this case.

Question 21

A differential cell count on a dog shows a greater than 15,000/uL lymphocyte concentration. You do a 4Dx test and the patient is negative for tick borne disease. What is your diagnosis?

Answer 21

Likely leukemia

Question 22

Acute lymphocytic leukemias are more common in what grouping of cats?

Answer 22

Younger, FeLV positive cats

Question 23

A dog presents for lethargy and swollen lymph nodes. MM are pale and the spleen feels large on palpation. You take a bone marrow aspirate and see many small, mature lymphocytes. Considering the species, what type of leukemia is most likely?

Answer 23

Chronic lymphocytic leukemia

Question 24

T/F: When considering diagnosis of a multiple myeloma, it is easiest to find proliferation of plasma cells on a blood film.

Answer 24

FALSE

Multiple myelomas occasionally release into the blood, but only in small numbers. Diagnose with a bone marrow aspirate.

Question 25

A bone marrow aspirate on a sick dog. What is the disease?

Answer 25

Multiple myeloma (neoplastic proliferation of plasma cells)

Question 26

A dog presents with lameness, epistaxis, and PU/PD. A fundic exam shows retinal hemorrhages, and xrays show lytic lesions in the bones. What laboratory finding will help lead you to your diagnosis?

Answer 26

Monoclonal or biclonal gammopathy

*This is Multiple Myeloma. Increased proteins will either be IgG or IgA. Bence Jones proteins may also be found in the urine.

Question 27

A FeLV positive cat has dysplastic myeloid cells on his blood smear. What disease is this a precursor to?

Answer 27

Leukemia

*Myeloid dysplasia is often pre-leukemic and is found in dogs and cats (FeLV or FIV positive), and rarely in horses.

Question 28

Chronic myeloproliferative neoplasms can be difficult to distinguish from _______.

Answer 28

Hyperplasia

Question 29

A sick, anemic dog comes in for routine bloodwork and on the CBC diff, neutrophil counts are over 100,000/uL with a left shift. A blood film shows cells with hypersegmented nuclei and giant metamyelocytes. What is the diagnosis?

Answer 29

Chronic granulocytic (myelogenous) leukemia

Question 30

In a dog with chronic granulocytic leukemia, what are the limitations of using a bone marrow biopsy for diagnosis?

Answer 30

Orderliness of maturation may appear disrupted with an inflammatory process, making it difficult to differentiate from a neoplastic process with incomplete maturation.

Question 31

How can we make a definitive diagnosis of chronic granulocytic leukemia, and effectively differentiate it from inflammatory disease?

Answer 31

Eventually you will see a disorderly left shift and “blast crisis”. Patients with leukemia are also much more anemic than patients with inflammatory disease.