Leucocyte and platelet abnormalities

Question 1

The production/release of WBCs is stimulated by?

Answer 1

Inflammatory cytokines from injured/infected areas

Question 2

Name the 5 major leucocytes in circulation

Answer 2

• Neutrophil
• Basophil
• Eosinophil
• Monocyte
• Lymphocyte

Question 3

Name the 3 granulocyte cells

Answer 3

• Neutrophils
• Basophils
• Eosinophil

Question 4

What are the largest and smallest leucocytes?

Answer 4

Largest = monocyte
Smallest = lymphocyte

Question 5

Which of the major leucocytes are involved in adaptive immunity?

Answer 5

Lymphocytes

Question 6

Which of the major leucocytes are involved in innate immunity?

Answer 6

Neutrophils and monocytes

Question 7

Numbers of WBCs above/below what figures in a single LPF 10x field would be a sign of

1. Leucopenia
2. Leucocytosis

Answer 7

1. < 18

2. > 50

Question 8

What is the method for performing a differential count on a blood smear?

Answer 8

Count 100 WBCs at 40x or 100x moving with a battlement pattern - 10 fields up, 1 field to the right, 10 fields right…etc
Need to do it in the body of the smear - not head or feathered edge

Question 9

What are the predominating cell type seen in different species?

Answer 9

Neutrophils in most species

Pig, sheep and cow may have more lymphocytes

Question 10

How do you calculate the absolute counts?

Answer 10

WBC count x % (in the species table)

Question 11

Define the following:

• Neutrophilia
• Neutropenia
• Left shift

Answer 11

• Neutrophil count above the upper reference limit
• Neutrophil count below the lower reference limit
• Number of juvenile neutrophils is above the upper reference limit

Question 12

When can neutropenia occur?

Answer 12

• severe overwhelming inflammation: sepsis, endotoxaemia, tumour necrosis
• bone marrow disease
• vitamin B12 deficiency

Question 13

What is a left shift an indicator of?

Answer 13

• Severe inflammation

- Immune mediated disease

Question 14

What is monocytosis and when can it occur?

Answer 14

Monocyte count above the upper reference limit

• Acute and chronic inflammation
• Tissue damage
• Leukaemia

Question 15

When can lymphocytosis occur?

Answer 15

• Chronic inflammation
• Adrenaline release in cats
• Leukaemia

Question 16

When can lymphopenia occur?

Answer 16

• Chronic inflammation
• Prolonged steroid in blood (stress leucogram)
• Viral disease e.g. feline infectious peritonitis

Question 17

When can eosinophilia occur?

Answer 17

• Parasitic disease

- Allergy: type 1 hypersensitivity

Question 18

A left shift is a sign of acute or chronic inflammation?

Answer 18

Acute

Question 19

What are the cell morphological changes when there is a toxic change?

Answer 19

Increased basophilia (blue colour) of the cytoplasm
Blue granules
Vacuoles

Question 20

What is the platelet reference interval in small animals?

Answer 20

150-500 x 10^9/L

Question 21

What is a giant platelet? What are increased numbers a sign of?

Answer 21

Diameter above RBC diameter

Increased numbers are a sign of increased thrombopoiesis

Question 22

How do platelet clumps affect platelet conc?

Answer 22

Give a falsely low platelet conc

Question 23

What are the causes of thrombopocytopenia?

Answer 23

• increased destruction of platelets
• Increased consumption of platelets
• Decreased production of platelets
• Redistribution

Question 24

What is a decreased production of platelets due to?

Answer 24

Destruction of megakaryocytes in bone marrow

Question 25

What are the clinical signs of severe thrombocytopenia?

Answer 25

• Petechiae (round spots on the skin as a result of bleeding)
• Ecchymoses (skin discolouration)
• Epistaxis (nosebleed)
• Melaena (digested blood in faeces)
• Haematochezia (blood in faeces)

Question 26

What are the reasons that thrombocytosis can occur?

Answer 26

• excitement
• chronic bleeding
• iron deficiency
• inflammation
• neoplasia