Abnormal Leukon: Neutropenia (Balasz) Flashcards
How are leukocytes measured using machines?
> impedence/optical
- RBC lysed
- nucleated cells streamed through channel where electrical impedence or optical deflection noted (NB. if RBC nucleated this will mess up value)
- most accurate for total numbers
quantitative buff ycoat (QBC)
- problems with abnormal cells/platelt enumeration
- ddx provided poor
How are leucocytes measured manually?
- chamber couunt/unopette system for birds/exotics
- blood smear estimate (count in a 100x field, divide by 4 ~= WBCx10e9: average at least 10 fields
What does the total white blood cell conc comprise?
- neutrophils
- lymphocytes
- monocytes
- eosinophils
- basophils (most difficult to count)
T1/2 of a neutrophils?
6 hours
What factos affect total leucocyte numbers?
- position of the leukocyte within the vessel (marginated v circulating) and availability for sampling
- balance between supply and demand
What are lecuocyte differentials? ECHO
- count 100 consequtive cells?
Percentage v absolute concentration neutrophils? ECHO
-
Outline stages of neutrophil poduction and kinetics
- proliferating
- maturating
- circulating
- tissue
What is the neutrophils stem cell?
- CFU-G (colony forming unit-granulocyte)
What stages exist within the proliferation pool? What is the proliferative pool and how long does it take for a neutrophil to pass thorugh this stage?
- Mb (myeloblast)
- Pg (progranulocyte)
- Me (Myelocyte)
> mitotic pool, stimulated by IL-1, 3, 6, GM-CSF, G-CSF
> apoptosis at myelocyte stage to limit production in health - 3d
What stages exist within the maturation pool? What is this pool and what measurements of it can be made?
- Mmc (metamyelocyte)
- B (Band neutrophil)
- S (segmeneted neutrophil)
> post mitotic pool - 2-3d in this pool
- MatNP:ProNP ratio should be 4-6
What is SNP/
- storage neutrophil pool
- subpool of matNP
- ready to be released to marrow sinusoids
What may be seen in bone marrow around developing neutrophils?
nRBC
Which pool is sampled during blood collection?
CNP (circulating neutrophil pool)
What is the MNP?
- marginated neutrophil pool
- ready to exit circulation and migrate to TNP
Wha is the CNP:MNP ratio? What should it be?
- CNP:TNP ~1
- cats ~3!
How long is the lag between ^ demand for neutrophils and hem entering the circulating pool?
~3d prolfierative, ~3d maturation (~6d)
How do toxic changes manifest in neutrophils?
- cytoplasmic foaminess and basophilia
- DOhle bodies (blue bits in cytoplasm)
- Giant neutrophils
- Vacuolatoon
- TOxic granules
Are “toxic changes” related to toxicity?
NO!!!
- can be with anything eg. IMHA etc. with rapid turnover
How do band neutrophils appear? Do they continue developing in the circulation?
- banded, not segmented (thinnest point not less than 2/3 thickest part)
WWhat is the difference between toxic and degenerate/lytic neutrophils?
> toxic - in peripheral blood - indicates accelerated production - no need for toxins > degenerate/lytic - in tissues (fluids) - fighting with bacteria - bacterial toxins
How can left shift be classified?
> regenerative - neutrophilia - segmented > bands > degenerative - neutropenia - bands > segmented
Which species have the greatest storage pool of neutrophils?
- cats and dogs
How does left shift classification differ between large and small animals?
> large animals no storage pool - numbers will drop rapidly - will recover when BM kicks in > smallies large storage pool - if you see a degenerative left shift this is BAAAD!! stores used up
What is right shift?
- hypersegmentation >5 lobes
- been in the circulation too long!
> something preventing adherence to walls of vessels
What is endotoxin neutropenia?
endotoxaemia - > neutrophils stick to the vessel walls
-^ marginated pool
What is the neutrophil equivalent of IMHA?
- macrophage destruction in tissues -> peripheral-destruction neutropenia
What 2 types of neutropenia result from incorrect production?
> granulocytic-hypoplasia neutropenia
> ineffective-production neutropenia
Causes of neutropenia d/t increasedd demand?
- peracute bacterial infeections (peritonitis, pyothorax)
- endotoxaemia
- immune mediated (alongside v neutrophil survival time)
Causees of neutropenia d/t redistribution?
- response to endotoxaemia, anaphylactic shock
- neutrophils ^ margination to vessel walls so fewer free to sample
Causes of neutropenia d/t decreased production?
> BM Disorders usually
- Infectious causes eg. parvo, FIV, FeLV, Ehrlichia
- Toxicity commonly iatrogenic eg. azathioprine, cyclophosphamide, idiosyncratic reactions
- Ineffective production: myelodysplasa often FeLV related
- change in BM environment (myelofibrosis, myelopthisis [crowding out by neoplasia]
- congential abnormalities: cyclical neutropenia of grey collies, CHediak-Higashi syndrome (neutropenia in cats)
What non-pathological factors affect neutropenia?
> Breed differences - greyhounds normally neutropenic! - referecne ranges not different > individual differnecess - if mild, track over time
What cut off level to give BS prophylaxis Abx exists for neutrophils?
different for different clinicians
- usually
Where are leukocytes produced? What else is required?
- BM (all cell lines)
- spleen and liver maintain potential to produce all lines
- thymes, spleen, LNs, bursa of Fabricus (birds): mostly involved in differentiation of lymphoid
- complex interplay of growth factors
Neutrophil t1/2 in blood?
5-10hrs
