Abnormalities of the Leukon Flashcards
Where are Leukocytes produced and where do they differentiate? (3/2)
Bone marrow (all cell lines!), spleen and liver
Thymus, lymph node- differentiation
How do we typically measure leukocytes in a lab using machinery?
Take blood sample- lyse the red blood cells and allow nucleated cells to stream through a channel where electrical impedance (flow) is noted- this is the total nucleated cell count (TNC)
What is a QBC Test?
Quantitative Buffy Coat Test- centrifugal test where machine scans a spun PCV tube and relates fractions to where each cell type settles
How do we measure leukocytes in exotic/ avian species and why?
Manual methods e.g. chamber counts because their RBC’s are nucleated and cannot be separated based on that notion
How do we make blood smear estimates?
From monolayer- assuming there’s no clots- count the number of leukocytes in this monolayer using x10 eyepiece & x10 lens
Then divide it by 4
Do this for 10 different fields of view
Which leukocyte is most dominant in dog/cat blood?
Neutrophils
Which leukocyte is most dominant in cow blood?
Lymphocytes
What is a Neutrophils half life?
6 hours
What cells are the CFU-G?
Colony forming unit granulocyte so basically self renewal cells
What happens in the ProNP proliferation pool?
Progranulocytes > Myelocyte
Stimulated by Interleukins & Colony stimulating factors
How long do neutrophils spend in the MatNP?
2-3 days maturing
What is the difference between the CNP:MNP (circulating vs marginated neutrophil pools) ratio in dogs vs cats?
CNP: MNP in dogs is 1:1
CNP: MNP is 3:1
When neutrophil demand is high…
more immature neutrophils are released (causing left shift)
What are immature neutrophils also known as and what do they look like?
Toxic neutrophils- foamy cytoplasms, no lobuled/ segmented nucleus, could be larger than normal
What is the difference between toxic and degenerative neutrophils? (3)
Toxic neutrophils are found in peripheral blood whereas degenerate neutrophils are found in tissues
Toxic neutrophils are that way due to accelerated production whereas degenerate are formed that way due to fighting with bacteria
Toxic neutrophils are regenerative & due to neutrophilia and degenerative are due to neutropenia
Degenerative neutrophils are ordinarily found in tissues fighting bacteria- what if we see them in the circulation?
Septicaemia!
What can cause ‘Right Shift’ aka Hypersegmented neutrophils?
Didn’t leave the MatNP fast enough due to downregulation of adhesion molecules
- Steroids
What are the 5 mechanisms of Neutropenia?
Inflammatory
Endotoxin
Peripheral destruction
Granulocytic hypoplasia
Ineffective production
What would cause Neutropenia due to increased demand?
Peracute bacterial infections
Endotoxaemia
Immune mediated
What would be some causes of Neutropenia due to decreased production?
Bone marrow disorders
Certain infectious causes such as Parvovirus, FeLV, FIV
Toxicities and drug reactions
What is different about Greyhounds when considering if an animal is Neutropenic?
Greyhounds naturally have lower neutrophil concentrations so need to remember to use greyhound specific reference intervels
What are the 5 mechanisms that cause Neutrophilia?
Acute inflammatory
Chronic inflammatory
Steroid neutrophilia
Physiologic neutrophilia
Chronic myeloid leukaemia
What pathologies may cause Neutrophilia due to increased demand? (3)
Infections- bacterial, viral etc.
Immune mediated diseases
Haemolysis, haemorrhage etc.
What may cause neutrophilia due to increased production independent of demand? (2)
Chronic Granulocytic leukaemia & Acute myeloid leukaemia- bone marrow overproduction
What may cause the leukocytes to persist in the circulation (and therefore cause Neutrophilia)?
Stress/ steroid response
Give an example of Physiologic Neutrophilia.
{think redistribution}
Stress/ excitement increases blood pressure- neutrophils are swept off vessel walls and into the circulation, increasing WBC numbers
What are Russel Bodies and where are they commonly found?
Eosinophilic inclusions that have failed to release its immunoglobulins- found usually in Lymph nodes but are commonly seen in Neoplasm
How do steroids cause Lymphopenia?
Via redistribution- Steroids disturb lymphocyte recirculation by inhibiting lymphocyte migration into the lymph nodes- steroids also in some cases cause lysis of lymphocytes too
What may cause a decreased production of Lymphocytes? (3)
Infection with parvovirus, FeLV etc.
Lympholytic drugs- chemotherapeutics e.g. Azathioprine
Immunodeficiencies where T & B cells are affected
How can Hypoadrenocorticism cause Lymphocytosis?
Lack of corticosteroid production which normally suppress lymphocyte production
Do monocytes have a storage, marginated or circulating pool?
Storage Pool- NO
Marginated & Circulating- Yes
Once monocytes leave circulation to go into the tissues…
they differentiate into macrophages
Monocytosis can occur secondary to immune neutropenia- how?
Monocytes come from the same precursors as Neutrophils- an increased demand of Neutrophils also increases monocytes- whilst the neutrophils get used up the monocytes remain
What may increase demand for Eosinophils? (4)
IL-5 release
Parasite antigens
Allergic disease such as drug allergy, asthma
Inflammation of mast cell rich tissue
How would a Paraneoplasm cause Eosinophilia?
By producing IL-5 which causes Eosinophil release
What pathologies do Basophils play a role in?
Type 1 hypersensitivities
Anaphylaxis
Rhinitis
Asthma
GI Sensitivities
What is a stress leukogram/ what changes does it induce?
Neutrophilia (high), lymphopenia (low), monocytosis (high), and eosinopenia (low)
Give an exogenous cause that would induce a stress leukogram?
Prednisolone/ any corticosteroid
What endogenous cause will induce a stress leukogram?
Cortisol
Would a stress leukogram help diagnose Addison’s?
Yes and No- the onset of clinical signs with a reverse/ lack of response matching a stress leukogram would be the indicator for addison’s
How can we use a stress leukogram to differentiate acute from chronic inflammation?
Acute- neutrophilia (^) with lymphopenia (↓)
Chronic- neutrophilia (^) with lymphocytosis (^)
Adrenaline causes….
Increased neutrophils (neutrophilia) and increased lymphocytes (lymphocytosis)
