Leucocyte and platelet abnormalities Flashcards
The production/release of WBCs is stimulated by?
Inflammatory cytokines from injured/infected areas
Name the 5 major leucocytes in circulation
- Neutrophil
- Basophil
- Eosinophil
- Monocyte
- Lymphocyte
Name the 3 granulocyte cells
- Neutrophils
- Basophils
- Eosinophil
What are the largest and smallest leucocytes?
Largest = monocyte Smallest = lymphocyte
Which of the major leucocytes are involved in adaptive immunity?
Lymphocytes
Which of the major leucocytes are involved in innate immunity?
Neutrophils and monocytes
Numbers of WBCs above/below what figures in a single LPF 10x field would be a sign of
- Leucopenia
- Leucocytosis
- < 18
2. > 50
What is the method for performing a differential count on a blood smear?
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
What are the predominating cell type seen in different species?
Neutrophils in most species
Pig, sheep and cow may have more lymphocytes
How do you calculate the absolute counts?
WBC count x % (in the species table)
Define the following:
- Neutrophilia
- Neutropenia
- Left shift
- Neutrophil count above the upper reference limit
- Neutrophil count below the lower reference limit
- Number of juvenile neutrophils is above the upper reference limit
When can neutropenia occur?
- severe overwhelming inflammation: sepsis, endotoxaemia, tumour necrosis
- bone marrow disease
- vitamin B12 deficiency
What is a left shift an indicator of?
- Severe inflammation
- Immune mediated disease
What is monocytosis and when can it occur?
Monocyte count above the upper reference limit
- Acute and chronic inflammation
- Tissue damage
- Leukaemia
When can lymphocytosis occur?
- Chronic inflammation
- Adrenaline release in cats
- Leukaemia
When can lymphopenia occur?
- Chronic inflammation
- Prolonged steroid in blood (stress leucogram)
- Viral disease e.g. feline infectious peritonitis
When can eosinophilia occur?
- Parasitic disease
- Allergy: type 1 hypersensitivity
A left shift is a sign of acute or chronic inflammation?
Acute
What are the cell morphological changes when there is a toxic change?
Increased basophilia (blue colour) of the cytoplasm
Blue granules
Vacuoles
What is the platelet reference interval in small animals?
150-500 x 10^9/L
What is a giant platelet? What are increased numbers a sign of?
Diameter above RBC diameter
Increased numbers are a sign of increased thrombopoiesis
How do platelet clumps affect platelet conc?
Give a falsely low platelet conc
What are the causes of thrombopocytopenia?
- increased destruction of platelets
- Increased consumption of platelets
- Decreased production of platelets
- Redistribution
What is a decreased production of platelets due to?
Destruction of megakaryocytes in bone marrow
What are the clinical signs of severe thrombocytopenia?
- 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)
What are the reasons that thrombocytosis can occur?
- excitement
- chronic bleeding
- iron deficiency
- inflammation
- neoplasia
