7 – WBC 1

Question 1

Kinetics

Answer 1

• WBC in blood are in TRANSIT

Question 2

Patterns

Answer 2

• Reflect basic process occurring in animal
• *to help decide what is going on in the animal

Question 3

What is leukopoiesis?

Answer 3

• Granulopoiesis: neutrophils, eosinophils, basophils
• Monopoiesis
• Lymphopoiesis
• takes time

Question 4

Neutrophil kinetics

Answer 4

1. Bone marrow: 6 days
   a. Storage pool if not needed right away
2. Peripheral blood: there for 10 hours
   a. Circulating pool=what is measured on CBC
   b. Marginating pool
   c. *can move back and forth between them
   d. **typically 1:1, except in cats: 1:3
3. Tissue pool: live for 12hrs then die

Question 5

Leukocyte kinetics: importance for CBC

Answer 5

• Other ones have marginating and circulating pools
• Movement between these pools can result in changes in cell numbers on CBC
  o similar to splenic contraction in erythrocytosis=re-distribution of cells and not actually new cells being produced

Question 6

Approach to leukogram

Answer 6

• use ABSOLUTE VALUES
• describe total WBC count and what each individual cell type is doing
• interpretation: look for patterns

Question 7

Physiologic leukogram: ‘excitement leukogram’

Answer 7

• Mild increase in
  o neutrophils
  o lymphocytes
  o monocytes
• Secondary to
  o Fear
  o Excitement
  o Pain
  o Strenuous exercise

Question 8

Physiologic leukogram: why does this happen?

Answer 8

• E release=decreased cells in margination pool
  o Shift from marginating to circulating
  o NO increase in cell production
• Neutrophils can increase up to 2x upper reference limit (cats: 2-4x URL)
  o Since equal cells in both pools (except in cats)
• *transient (20-30mins): appears and disappears quickly

Question 9

Steroid leukogram: ‘stress leukogram’

Answer 9

• Mild increase in neutrophils
• **decreased lymphocytes
• Increased monocytes
• (decreased eosinophils: but in many labs the reference interval goes to 0)

Question 10

Steroid leukogram: what is it secondary to?

Answer 10

• Glucocorticoids
  o Stress of illness (endogenous)
  o Hyperadrenocorticism (endogenous)
  o Glucocorticoid therapy (exogenous)

Question 11

Steroid leukogram: after single dose, ‘time frame’

Answer 11

• Develops within 4-8 hrs
• Resolves within 24hrs
• Highly dependent on dose and duration

Question 12

Steroid leukogram: increased neutrophils

Answer 12

• Shift from marginating to circulating pool
• Decreased margination
• Decreased tissue migration
• Increased release from storage pool in the marrow
• *2-4x URL in dogs

Question 13

Steroid leukogram: decreased lymphocytes

Answer 13

• Shift from circulating pool to lymph nodes or bone marrow
• *long term=lymphotoxic effect
  o Decreased lymphopoiesis
  o Lymphocytolysis

Question 14

When you have a clinically ill animal, what do you expect?

Answer 14

• A steroid (stress) leukogram
• If don’t see=significant
  o Think about HYPOADRENOCORTISM

Question 15

What might explain a ‘stress’ hyperglycemia?

Answer 15

• Excitement/fright hyperglycemia
  o Due to E release
  o Up to 17 mmol/L in cats
  o Will decrease in 30 mins
• Steroid-associated hyperglycemia
  o Due to glucocorticoids
• Post-prandial hyperglycemia

Question 16

Inflammatory leukogram: what is happening?

Answer 16

• Mediated by inflammatory cytokines
• Increased tissue demand for inflammatory cells
• Bone marrow recruited to PRODUCE more cells

Question 17

What are the bone marrow tricks to ‘survive’ infectious disease processes?

Answer 17

• Release mature neutrophils from storage pool
• Release immature neutrophils=LEFT SHIFT (only by human looking)
• Increase speed of production=TOXIC CHANGE (only by human looking)

Question 18

Classic inflammatory leukogram: what do we see?

Answer 18

• Mild to marked increase in neutrophils
• *increased bands (LEFT SHIFT)
• +/- toxic change
• Metamyelocytes, myelocytes
• Monocytes WRI or increased
• +/- thrombocytosis

Question 19

What is left shift?

Answer 19

• Shift toward IMMATURITY
• Early release of neutrophil precursors from bone marrow
• Bands, occasionally metamyelocytes

Question 20

What can cause an inflammatory leukogram?

Answer 20

• Infectious agents
• Necrosis
• Neoplasia
• Immune-mediated
• *inflammation does NOT equal infection
• *can have localized inflammation WITHOUT leukogram changes

Question 21

What might neutrophilia result from?

Answer 21

• Shifting of cells
  o Storage pool to circulating pool
  o Marginating pool to circulating pool
• Decreased tissue migration
• Increased bone marrow production