Lecture 4 Flashcards
1
Q
What are the 4 progressive stages to toxic neutrophils?
A
Dohle bodies
Cytoplasmic basophilia
Cytoplasmic vacuolation
Cytoplasmic granulation
2
Q
What do Dohle bodies look like?
A
Pale, round to linear blue aggregates in the cytoplasm
3
Q
What do the presence of Dohle bodies indicate?
A
- Can be normal if present in small numbers
- more abundant in cats
- often the first sign of toxic change
4
Q
What do neutrophils with cytoplasmic basophilia look like?
A
Blue coloured cytoplasm due to retained ribosomes
May be focal, streaked or diffuse
5
Q
What is the first toxic change seen in a neutrophil?
A
Dohle bodies
6
Q
What is the last toxic change to resolve with recovery of disease?
A
Cytoplasmic basophilia
7
Q
What does cytoplasmic vacuolation look like in a toxic neutrophil?
A
- Frothy or vacuolated cytoplasm ( represents degranulation of lysosomes)
- Often seen with cytoplasmic basophilia
- Often a more sever sign of toxic disease than cytoplasmic basophilia
8
Q
What do neutrophils with cytoplasmic granulation look like?
A
Distinct red granules in the cytoplasm due to the primary granules taking up stain
9
Q
What toxic neutrophil is more common in large animals?
A
Toxic granulation
10
Q
What is hyper segmentation in a neutrophil and what does it indicate?
A
- 5 or more lobes
- Only tells us they are old neutrophils
11
Q
What can hypersegmented neutrophils indicate in cattle?
A
Cobalt deficiency
12
Q
What can hypersegmented neutrophils indicate in goats and horses?
A
Idiopathic
13
Q
What animal are hypersegmented neutrophils a hereditary finding?
A
Poodles
14
Q
What is ‘Pelger-Huet anomaly?’
A
An inherited disorder characterized by the hyposegmentation of neutrophils whereby the nucleus of the cells has only 2 lobes or no lobes at all.
15
Q
What can pseudo Pelger-Huet anomaly be associated with?
A
Chronic infection ( but no real significance)
16
Q
What abnormality can be found in Birman cats?
A
Neutrophil Granulation anomaly
- autosomal recessive disorder of Birman cats
- Neutrophils have fine eosinophilia to magenta granules
- Neutrophil function is normal
17
Q
What is a common lysosomal disorder in cats?
A
Chediak-Higashi syndrome
- neutrophils, eosinophils and occasional lymphocytes contain large lysosomal granules that are visible on romanowsky stained blood smears.
18
Q
How does Chediak-Higashi syndrome affect cats?
A
Affected cats tend to bleed because platelet function is abnormal.
Otherwise cats are healthy
19
Q
What causes reactive lymphocytes?
What animals is it typically seen in?
A
Seen as a response to antigenic stimulation
- More frequently seen in younger animals who are antigenically naive
20
Q
What do reactive lymphocytes look like?
A
- friable
- cytoplasm may appear indented by rbc’s
21
Q
What do lymphoblasts look like?
What do they indicate?
A
- Usually indicate lymphom or leukaemia
- clump together
22
Q
What do degranulated eosinophils and basophils look like?
A
They appear moth eaten because of cytoplasmic degranulation and vacuolation
23
Q
Where can we see inclusions for canine distemper virus?
which cells?
A
This round, dark inclusions can be seen in the cytoplasm of erythrocytes, neutrophils, monocytes, lymphocytes
24
Q
What are morulae and what can they indicate?
A
Colonies of bacteria in neutrophils and eosinophils
- Seen in ehrlichia and anaplasma
25
What is another name for basket cells?
| What are they?
Smudge cells
- They are degenerative Leukocytes that have ruptured.
26
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
27
What is the name of the cell that is the source of platelets and where is it found?
Megakaryocyte found in the bone marrow
28
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
29
What are large platelets called?
Megathrombocytes, Giant platelets, Macroplatelets, Shift platelets
30
How big is a shift platelet?
A bit larger than the average erythrocyte in the species
31
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
32
What are reticulated platelets?
Young platelets ( Usually larger than average platelet)
33
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
34
What species is prone to platelet clumping?
Cats and horses
35
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
36
What are microplatelets?
platelet fragments. <1.0um in diameter
37
What causes microplatelets?
Artifact- aging in EDTA over 24hrs
| Real- Seen in iron deficiency anemia and Immune mediated thrombocytopenia
38
What is MPV ( mean platelet volume) and what is its measurement?
Reflects the average size of platelets in the circulating population.
Determined by automated cell counters
Femtoliters
39
What morulae inclusion on platelets can cause cyclic thrombocytopenia in dogs?
Anaplasma platys
40
What is hemostasis?
Arrest of bleeding physiologically ( vasoconstriction and coagulation) or surgically
41
What is the first stage of hemostasis?
Primary- formation of the platelet plug. Adhesion of platelets requires Von Willebrand's factor to stabilize the plug
( fragile at this stage)
42
What is the secondary stage of hemostasis?
Formation of fibrin through the coagulation cascade.
- Fibrin strands provide a more stable clot
- Allows healing of the damaged tissue
- Involves the coagulation cascade
43
What is the tertiary stage of hemostasis?
Formation of plasmin for degradation of clot
| - The clot has to be loses to prevent occlusion of the vessel
44
How is the coagulation cascade traditionally separated?
Intrinsic pathway - PTT
Extrinsic pathway - PT
Common Pathway
45
What is on the surface of activated platelets and what does it do?
Phosphatidylserine -released microparticles from platelets
Coagulation complexes attach to PT
46
What can cause prolonged clotting time?
Artifactual- poor collection and handling
- Excitement: stress in animals can cause venous stst
Use vacutainer to avoid this
47
What tube is preferred analysis of coagulating assays?
Blue Top - Sodium Citrate
48
How much blood should be added to a blue top tube?
Sodium Citrate:Blood
| 1:9
49
For coagulation testing, how should the sample be prepared and shipped?
Centrifuge at 2000 rpm for 10-15min
Remove plasma ASAP
Store and refrigerate...ship asap
50
What are 3 in-clinic tests we can do for hemostasis?
1. Platelet Estimate on a blood smear
2. Buccal mucosal bleeding time ( 1-5min)
3. Activated clotting time
51
How do we perform an activated clotting time test?
Prewarm grey top tube with diatomaceous earth. Add 2mls blood, mix once by gentle inversion. 37'C water bath
Normal clot formation 60-90 seconds
Prolonged can = sever thrombocytopenia
52
What is a clot reaction test?
Measures the amount of time for the clot to retract from the sides of the glass container...
Clot formation in 60 sec
Clot retraction in 4 hours
Compact clot in 24 hours *crude test not commonly used
53
What are some routine coagulation tests offered by external laboratories?
```
PT
A PPT
Fibrinogen concentration
Fibrinogen degradation products
Factors II, V, VII, IX,X,XI,XII
```
54
What test will check for Vitamin K deficiency/antagonism?
PT - Prothrombin Time
| *Not first choice test but can test sensitivities
55
Why is vitamin K important?
It is produced in the liver and is important for 4 clotting factors
II,VII,IX,X
56
What test find proteins that indicate vitamin K absence?
PIVKA
Proteins induced vitamin k absence
-the test detects precursor proteins to these factors that bind up in the absence of vitamin K
57
What is DIC?
Disseminated Intravascular Coagulation
- It is a bleeding problem in which clotting factors are activated with an absence of injury. Micro clots form within the blood vessels, and the clotting material goes on to consume platelets and proteins, using them up and leaving a lack of sufficient factors. Can lead to disruption in normal blood flow to the organs and excess bleeding both internally and externally
58
What is Von Willebrand's disease?
A disease caused by a deficiency of vWF which is an adhesive glycoprotein in the blood that is required for clotting = platelet adhesion
-Most common inherited bleeding disorder
59
What are the 3 types of Von Willebrand's disease?
Type 1- lower than normal amounts of vWF
Type 2- structurally abnormal vWF
Type 3 - no vWF at all
60
What are the two classifications of neoplastic disorders of hematopoeisis?
Lymphoproliferative
| Myeloproliferative
61
What is leukaemia?
A term used for the presence of neoplastic cells in the blood?
62
Anemia is a decrease below normal in .....(3)?
- The amount of rbc's/uL blood
- PCV
- Hb concentration
* it is disequilibrium between blood loss and blood production
63
Anemia is classified in 3 ways...
1. RBC size and hemoglobin concentration MCV/MCHC
2. Bone marrow response...regenerative vs non regenerative
3. Etiology..Hemolytic, decreased or defective rbc production
64
What is macrocytic anemia?
Most common is regenerative anemia.
65
What is microcytic anemia?
Most common cause is iron deficiency due to chronic blood loss or nutritional deficiency
66
How long after blood loss does it take for the bone marrow to respond normally?
The bone marrow should increase production of erythrocytes within 2-4 days
67
What is the best way to assess if anemia is regenerative?
Perform a reticulocyte count
68
What might be our findings with regenerative anemia?
- Polychromasia
- Reticulocytosis with Anisocytosis and increased RDW
- Macrocytosis and hypochromasia
- Basophilic stippling in ruminants
- Increased # of nucleated rbc's and Howell Jolly bodies
69
What might cause regenerative anemia?
Hemolysis
| Hemorrhage
70
Regenerative anemia response is seen greatest to least in what species?
```
Birds
Dogs
Cats
Cows
Horses
```
71
What indicators will we see in non-regenerative anemia?
Lack of time- takes 2-4 days or longer for bone marrow response
Lack of bone marrow response
72
What can cause a lack of bone marrow response?
- Renal Failure (because kidneys not producing erythropoietin)
- Iron deficiency
- Aplastic anemia
- Endocrine disorders
73
What are some causes of anemia?
Hemolytic-Immune mediated, RBC parasites, bacterial or viral agents, toxins
Injury - hemorrhage
Nutrition or chronic blood loss - Iron deficiency
Production disorders- renal disease, lead poisoning, iron or copper deficiency, hormone related
74
Are Dohle bodies seen in peripheral blood of healthy animals?
Can be normal if present in small numbers
| More abundant in cats
75
The PCV is normal, the MCV is increased and the MCHC is wnl. Describe the anemia.
Regenerative anemia
76
What does the term hyposegmentation mean?
Low number of segments in the neutrophil (usually 2)
| Associated with Pelger-Huet anomaly
77
What is seen in the peripheral blood smears of cats with Chediak-Higashi syndrome?
Neutrophils, Eosinophils and occasional lymphocytes with large lysosomal granules that are visible with romanowsky stain.
78
What do reactive lymphocytes in a peripheral blood smear indicate?
Response to antigenic stimulation
79
Describe the appearance of reactive lymphocytes
- Friable
| - Cytoplasm may appear indented by rbc's
80
What disease is associated with lymphoblasts in the peripheral blood?
Lymphoma or Leukemia
81
What are 2 causes of artifacts all platelet clumping in blood?
Poor Venipuncture
| Inadequate anticoagulation
82
What is important to remember when collecting blood for coagulation testing?
- Coagulation factors are unstable
- Samples should be submitted ASAP
- Centrifuge immediately and remove plasma from tube
- Refridgerate
83
What blood test would be fairly specific for rodenticide poisoning and why?
PIVKA
84
What is a saline test?
Confirms the presence of agglutination by mixing a drop of uncoagulated blood with a larger drop of saline.
Apply coverslip to slide and check
True Agglutination- rbc's will remain clumped
If rouleaux- rbc's will spread out individually
85
What does a direct antiglobulin or Coombs test work?
Used to confirm IMHA
An animal with IMHA has autoantibodies bound to the surface of its rbc's. Coombs reagent, with antibodies against IgG, IgM, and complement is added
Agglutination occurs as Coombs antibodies bind to the autoantibodies on the surface of the rbc's.
86
How do we perform a reticulocyte count?
Count 1000 rbc's including Reticulocytes and determine %
- To count 1000 rbc's you count 10 fields in the monolayer. Each field has approx 100 rbc's in it therefore 10 fields = 1000.
Then calculate % of Reticulocytes
87
What animal can we not do a reticulocyte count on?
Horse. We will never see Reticulocytes in their peripheral blood.
88
How do we prepare a slide for a reticulocyte count?
-Mix a few drops of blood with equal amount of NMB stain in a tube. Mix gently and let sit for 15-20min
Or
-Drop of blood with drop of NMB on slide, mix, let sit for 5 min and go.
89
How do we perform an absolute reticulocyte count?
| To get x 10 3/uL or x 10 9/L
Reticulocyte % x rbc count x 10
Therefore if the dog has a reticulocyte count of 3% and rbc count of 1.5 x 10 3/uL
= 45 x 10 3/uL
90
How do we perform a corrected reticulocyte count?
% of reticulocytes x PCV divided by normal average hematocrit
35% in cats and 45% in dogs
Example - 10% and a PCV of 20%
10 x 20 divided by 45 = 4.4%
