WBC 1: Neutrophilia Flashcards
WBC importance
-immune function
-assert themselves outside the vasculature
Leukopoiesis
- Granulopoiesis: neutrophils, eosinophils, basophils
- Monopoiesis
- Lymphopoiesis
Granulopoiesis timing
Takes 6 days from myeloblasts to mature neutrophil
Neutrophil kinetics
1.Formed in the bone marrow and hang out in the storage pool (6 days)
- Move into the peripheral blood into either the circulating pool or the marginating pool (10days)
- Tissue pool (12 hrs- undergo effects and then die)
What is the marginating pool and circulating pool?
Circulating= where you would take a blood sample. The only neutrophils we see on samples
Marginating= neutrophils rolling along sides of vessels
Marginating to circulating ratio
Normally 1:1
EXCEPT in cat, who have 3:1 ratio (more in marginating pool
Are neutrophils the only leukocytes to have marginating and circulating pools?
No, other leukocytes have them as well.
Movement of cells between these pools can result in changes in cell numbers on the CBC
How to look at leukograms
- Always use the absolute values
- Description (describe total WBC count and what each individual cell type is doing)
- Interpret patterns
WBC changes terms
What are the three leukogram patterns?
- Physiologic leukogram
- Steroid leukogram
- inflammatory leukogram
Physiologic Leukogram
Called an excitement leukogram (fear, pain, excitement, strenuous exercise)
-increased (mild) neutrophils, lymphocytes, monocytes
Grading neutrophilia
Species variation in inflammatory neutrophilia
-dogs max magnitude of neutrophilia is much higher, followed by cats, then horses, then cows
How does a physiologic leukogram occur?
- Epi release leading to decreased margination
- Shift from marginating pool into the circulating pool
**no increased cell production, just movement
**transient- appears and disappears (20-30mins)
**neutrophils can increase up to 2x upper reference limit (3-4x in cats because they have more cells in marginating pool to begin with)
Steroid leukogram pattern
-increased neutrophils (mild)
-decreased lymphocytes **most important factor
-increased monocytes
-decreased eosinophils
What causes steroid leukograms?
Glucocorticoids from:
-stress of illness
-hyperadrenocorticism
-glucocorticoid therapy (exogenous)
What occurs after a single dose of glucocorticoids?
-Steroid leukogram develops in 4-8hrs
-Resolves within 24hrs
**highly dependent on dose and duration
How does the increase in neutrophils in a steroid leukogram occur?
- Increased neutrophils because shift from marginating to circulating pool; decreased margination and migration into tissues
2.Increased release from storage pool in the marrow
**see 2-4x increase in dogs
How does the decrease in lymphocytes in a steroid leukogram occur?
- Shift from circulating pool to lymph nodes or bone marrow
- Long term steroids leads to a lymphotoxic effect decreasing lymphopoiesis and resulting in a lymphocytolysis
What is indicated when you have a clinically ill animal (dog) but you do not see a stress leukogram?
Suspect hypoadrenocorticism
Inflammatory leukogram pattern
Mediated by inflammatory cytokines indicating an increased tissue demand for inflammatory cells and therefore the demand for the bone marrow to produce more cells
How can the Bone marrow produce neutrophils quickly when inflammatory cytokines indicate a demand?
1.Can release mature neutrophils from storage pool
- can release immature neutrophils (left shift)
- Can increase speed of production which leads to toxic change
What is shown on a classic inflammatory leukogram?
-increased neutrophils (mild to marked)
-increased bands (indicating left shift)
-potential for toxic change
-potential for metamyelocytes or myelocytes (younger than bands)
-monocytes normal or increased
-potential for thrombocytosis
**analyzer cannot find bands or toxic change.. must be done by a person
Left shift
Shift toward immaturity
- early release of neutrophil precursors from bone marrow
=bands, occasionally metamyelocytes
Causes of inflammatory leukograms
-infectious agents
-necrosis (infarcts)
-neoplasia
-immune mediated (IMHA)
-sterile foreign body
**inflammation does not equal infection AND local inflammation can occur without leukogram changes
Leukogram neutrophilia potentials chart
