Lecture 4 Flashcards
What are the 4 progressive stages to toxic neutrophils?
Dohle bodies
Cytoplasmic basophilia
Cytoplasmic vacuolation
Cytoplasmic granulation
What do Dohle bodies look like?
Pale, round to linear blue aggregates in the cytoplasm
What do the presence of Dohle bodies indicate?
- Can be normal if present in small numbers
- more abundant in cats
- often the first sign of toxic change
What do neutrophils with cytoplasmic basophilia look like?
Blue coloured cytoplasm due to retained ribosomes
May be focal, streaked or diffuse
What is the first toxic change seen in a neutrophil?
Dohle bodies
What is the last toxic change to resolve with recovery of disease?
Cytoplasmic basophilia
What does cytoplasmic vacuolation look like in a toxic neutrophil?
- Frothy or vacuolated cytoplasm ( represents degranulation of lysosomes)
- Often seen with cytoplasmic basophilia
- Often a more sever sign of toxic disease than cytoplasmic basophilia
What do neutrophils with cytoplasmic granulation look like?
Distinct red granules in the cytoplasm due to the primary granules taking up stain
What toxic neutrophil is more common in large animals?
Toxic granulation
What is hyper segmentation in a neutrophil and what does it indicate?
- 5 or more lobes
- Only tells us they are old neutrophils
What can hypersegmented neutrophils indicate in cattle?
Cobalt deficiency
What can hypersegmented neutrophils indicate in goats and horses?
Idiopathic
What animal are hypersegmented neutrophils a hereditary finding?
Poodles
What is ‘Pelger-Huet anomaly?’
An inherited disorder characterized by the hyposegmentation of neutrophils whereby the nucleus of the cells has only 2 lobes or no lobes at all.
What can pseudo Pelger-Huet anomaly be associated with?
Chronic infection ( but no real significance)
What abnormality can be found in Birman cats?
Neutrophil Granulation anomaly
- autosomal recessive disorder of Birman cats
- Neutrophils have fine eosinophilia to magenta granules
- Neutrophil function is normal
What is a common lysosomal disorder in cats?
Chediak-Higashi syndrome
- neutrophils, eosinophils and occasional lymphocytes contain large lysosomal granules that are visible on romanowsky stained blood smears.
How does Chediak-Higashi syndrome affect cats?
Affected cats tend to bleed because platelet function is abnormal.
Otherwise cats are healthy
What causes reactive lymphocytes?
What animals is it typically seen in?
Seen as a response to antigenic stimulation
- More frequently seen in younger animals who are antigenically naive
What do reactive lymphocytes look like?
- friable
- cytoplasm may appear indented by rbc’s
What do lymphoblasts look like?
What do they indicate?
- Usually indicate lymphom or leukaemia
- clump together
What do degranulated eosinophils and basophils look like?
They appear moth eaten because of cytoplasmic degranulation and vacuolation
Where can we see inclusions for canine distemper virus?
which cells?
This round, dark inclusions can be seen in the cytoplasm of erythrocytes, neutrophils, monocytes, lymphocytes
What are morulae and what can they indicate?
Colonies of bacteria in neutrophils and eosinophils
- Seen in ehrlichia and anaplasma
What is another name for basket cells?
What are they?
Smudge cells
- They are degenerative Leukocytes that have ruptured.
What do smudge cells indicate?
- Large numbers may be associated with leukaemia
- Artifact caused by blood being stored too long before making the blood smear or too much pressure applied when making smear
What is the name of the cell that is the source of platelets and where is it found?
Megakaryocyte found in the bone marrow
What does the platelet distribution width (PDW) tell us?
An indication of variation in platelet size which can be a sign of active platelet release
What are large platelets called?
Megathrombocytes, Giant platelets, Macroplatelets, Shift platelets
How big is a shift platelet?
A bit larger than the average erythrocyte in the species
Why do some platelets stain faintly and what species is faint colour and low platelet count considered normal?
Faint staining caused by lack of granulation in the cytoplasm
- horse
What are reticulated platelets?
Young platelets ( Usually larger than average platelet)
What causes platelet clumping and how can we assess if there is platelet clumping?
Can be caused by poor venipuncture or inadequate anticoagulant
Perform a blood smear to confirm
What species is prone to platelet clumping?
Cats and horses
When platelets are absent on a smear, what can we do to confirm?
- Examine the tube with the blood sample…rock the tube gently to look for clots.
- Uncap the tube and run a wooden stick through the blood to ‘catch up’ small clots
What are microplatelets?
platelet fragments. <1.0um in diameter