WBC Flashcards
What are the main types of leukocytosis
Neutrophilia
Lymphocytosis
Monocytosis
Eosinophilia
Basophilia
What are the main types of leukopenia
Neutropenia
Lymphopenia
Monocytopenia
Eosinopenia
What are the 3 steps that need to occur for cells to leave blood vessels?
Marginalisation
Adhesion
Migration
Explain circulating vs marginal pool
Some WBCs (esp. neutrophils) exist in 2 pools within blood vessels: circulating (freely flowing in bloodstream) & marginal pool (briefly adhered to vessel walls)
Certain factors can cause shift from marginal to circulating pool, leading to increase in measurable WBCs in blood sample
What factors can produce a shift from marginal to circulating pool?
Epinephrine
Glucocorticoids
Infection
Stress
What determines the neutrophil count in the bloodstream?
neutrophil count depends on balance between:
- Neutrophils leaving blood to fight infection in tissues
- Bone marrow production & release of new neutrophils
How does inflammation affect neutrophil concentration?
Inflammatory conditions usually increase neutrophil count because bone marrow releases more
Severe inflammation can decrease neutrophil count if neutrophils are used up faster than bone marrow can replace them
A normal or low neutrophil count (neutropenia) in severe infections may indicate overwhelming inflammation
What are common causes of neutrophilia?
Inflammation
- Infections
- Immune mediated anaemia
- Necrosis
Steroid
- Stress
- Steroid therapy
- Hyperadrenocorticism
Physiological
- Epinephrine
- Fight or flight (excitement, fear, pain, exercise)
Chronic neutrophil leukaemia
Paraneoplastic
Give examples of mechanisms and causes of neutrophilia
What is the difference between a left shift and a right shift in neutrophilia?
Left shift: Increase in immature neutrophils, occurs in response to infection/inflammation
Right shift: Increased hypersegmented neutrophils due to prolonged circulation (e.g., glucocorticoid effect)
What is a regenerative left shift?
Segmented (mature)>immature
Neutrophils ↑
What is a degenerative left shift?
Immature>segmented
Neutrophils ↔ ↓ or (↑)
(bad news)
How do glucocorticoids cause a right shift?
Glucocoticoids down-regulate adhesion molecules, less neutrophils leave circulation to die, aged cells remain in circulation
(decreased extravasation into tissues)
What is neutrophil toxic change?
Rapid neutropoiesis (production)
Usually severe bacterial infection (high demand)
(Blood analysers cant tell about neutrophil toxic change, only seen via blood smear analysis)
What are signs of toxic neutrophil changes?
Less condensed chromatin (nucleus appears less mature)
Bluer cytoplasm due to retained ribosomal RNA
Cytoplasmic basophilia (focal, streaked, or diffuse)
Döhle bodies (pale blue inclusions of ribosome aggregates)
Frothy or vacuolated cytoplasm (lysosomal degranulation)
Larger cell size compared to normal neutrophils
Label the neutrophils
What are some common neutrophil inclusions?
Bacterial
- Ehrlichia, Anaplasma
Viral
- Canine distemper
Protozoa
- Toxoplasma
- Hepatozoon
Fungi
- Histoplasma
Hereditary/metabolic
-Chediak-Higashi, Birman cat anomaly, mucopolysidosis
What are heterophils and what species have them?
Functionally equivalent to neutrophils but granules stain red
What are some common causes of neutropenia?
Inflammation
- overwhelming bacterial infections
Decreased production:
- infection
- toxicity
- neoplasia
- marrow necrosis
- myelofibrosis
Immune mediated
Describe the neutrophil bone marrow reserve and regenerative capacity in dogs, cats, horses & cows
Describe the interpretation of neutropenia in acute inflammation in dogs, cats, horses and cows
Describe the order of progression of cytopenia when there is marrow disruption
Describe the features of a reactive lymphocyte
More cytoplasm
more cytoplasm basophilia
Perinuclear halo
Prominent golgi zone
larger, eccentric, cleaved nucleus
Larger cells
Give examples of causes of lymphocytosis
Physiological:
- catecholamine mediated via splenic contraction
Chronic inflammation:
- chronic antigenic stimulation
young animals & recent vaccination
Lymphoproliferative disorder (e.g., FeLV)
Hypoadrenocorticism (glucocorticoids inhibit lymphocytes)
Give examples of causes of lymphopenia
Stress/steroid:
- glucocorticoids shift lymphocytes out of circulation & stimulates lymphocytolysis
Acute inflammation:
- migration to inflamed tissue & homing to LNs
Loss of lymph:
- chylothorax
Cytotoxic drugs
Radiation
Immunodeficiency
Lymphoma
What is the primary function of monocytes?
Differentiate into macrophages in tissues for phagocytosis and cytokine release
Give examples of causes of monocytosis
Inflammation
- May imply “chronic”
- Bacterial, fungal, protozoal
- Necrosis
Steroid/Stress
- Glucocorticoids (occ ACTH)
- Hyperadrenocorticism
Monocytic/myelomonocytic leukaemia
Give examples of causes of eosinophilia
Hypersensitivity
Parasitism
Hypoadrenocorticism
Paraneoplastic
Idiopathic eosinophilic syndromes
Give examples of causes of eosinophilia
Glucocorticoids, stress, inflammation
Describe presence of basophils in blood
Extremely rare traffic from blood to tissue – will almost never find on blood smears
Describe appearance of basophils
What can cause presence of nucleated red cells?
regenerative anaemias
lead toxicity
Extramedullary haematopoiesis
Splenic contraction
Damaged marrow
erythroleukemia
How do excitement and stress leukograms differ?
Excitement (catecholamines): Neutrophilia + lymphocytosis (especially in cats)
- (resolves within hours)
Stress (glucocorticoids): Neutrophilia, lymphopenia, eosinopenia!, ± monocytosis.
