Flashcards in Pathology Deck (311)
Do juvenile RBCs contain a nucleus?
No, but they do contain residual RNA and organelles
Where do reticulocytes migrate to?
Through transient apertures in endothelial cells into venous sinuses
Mature after 24 hours in blood
What morphological changes would we see with accelerated erythropoiesis?
How is thrombopoietin production and clearance controlled?
Produced constantly, mainly by liver
Cleared by receptor-mediated uptake and destruction by platelets and megakaryocytes
However, interleukin 6 can increase TPO synthesis, independent of PLT numbers. Iron deficiency increases thrombopoiesis independently of TPO
What is MCV?
Mean corpuscular volume
Average erythrocyte size
What is MCHC?
Mean corpuscular Hb concentration
Average erythrocyte Hb concentration
What is MCH?
Mean corpuscular Hb
Average erythrocyte Hb per cell
What kind of anaemia is present if there is raised MCV?
What about reduced MCV?
Macrocytic anaemia (presence of larger cells which are usually juvenile RBCs-regenerative anaemia)
Microcytic anaemia (production of small erythrocytes, likely due to less haemoglobin available for erythropoiesis caused by iron deficiency)
What kind of anaemia is seen with reduced MCHC?
Seen with regeneration (juvenile RBCS have lower Hb concentration) or iron deficiency
Which stains could you use to identify reticulocytes?
New Methylene Blue (stains RNA in ribosomes)
How do you calculate an absolute reticular count?
% retic x RBC (10^12/L) x 10
Which values for absolute reticular count in dogs and cats are a sign of non-regenerative anaemia?
What is the general term for abnormal RBC shape?
What are the causes of regenerative anaemia?
Haemolysis (destruction of RBCs)
What are the causes of non-regenerative anaemia?
Lack of erythropoietin
What is blood loss anaemia?
Proportional loss of all blood components (plasma and cells)
Can be acute or chronic
1. Initial decrease of blood volume, while proportion of plasma and cells is maintained. Hct and TP are unchanged
2. Within a few hours, activation of mechanisms to maintain volaemia -> influx of H2O from extracellular space -> dilution -> reduction of Hct and total protein
(Hct-ratio of volume of RBCs to a given volume of blood)
What are 2 causes of blood loss anaemia?
Presence of spherocytes is strongly supportive of what?
Immune-mediated haemolytic anaemia
Macrophages partially phagocytise RBCs at the part of the membrane where the antigen-antibody complex is, causing loss of the discoid shape
What is agglutination?
Antibody-mediated clumping of RBCs
Stongly supportive of immune-mediated haemolytic anaemia
What is rouleaux formation?
What is it caused by?
In which species is it normal?
Stacking of RBCs due to increased plasma proteins coating RBCs
Caused by inflammation, cancer
Horses and cats
How can you differentiate between agglutination and rouleaux formation?
Saline agglutination test
Add 9 drops of saline to 1 drop of blood. Rouleaux formation will disappear, whereas agglutination persists
Which values for WBC in a single field are indicative of leucopenia and leucocytosis?
If 50 WBC in a single LPF10x field then likely leucocytosis
What do we look for at the tail end of a blood smear?
Erythrocytes will be ruptured here
Give some causes of neutropenia
Bone marrow disease eg neoplasia, immune-mediated destruction of precursors
Overwhelming tissue demand
Reduced bone marrow production
Increased destruction of neutrophils
What is left shift?
What causes it?
Increased number of juvenile neutrophils (band or earlier stages) released from bone marrow
Due to severe acute inflammation
(Also bacterial infection, immune-mediated disease (e.g. IMHA))
What causes monocytosis? (monocyte count above upper reference limit)
Chronic inflammation / tissue damage / necrosis (usually combined with neutrophilia)
‘Stress leucogram’ or steroid administration (combined with neutrophilia, lymphopenia and eosinopenia)
What causes lymphocytosis? (Lymphocyte count above upper reference limit)
Adrenaline release in cats
What causes lymphopenia? (lymphocyte count below upper reference limit)
Chronic inflammation (seen with neutrophilia)
Stress leucogram (effect of prolonged steroid in blood)
Viral disease eg FIV, FIP
What causes eosinophilia? (eosinophil count above upper reference limit)