Abnormalities of the Erythron Flashcards
What is different about the shape of Camelid RBC’s?
they’re elliptical shape
What is different about avian and reptile RBC’s?
RBC’s are nucleated
Where are RBC’s produced in both foetus and adults?
Liver/spleen in foetus
Bone Marrow- specifically in long bones in adults [liver and spleen do retain some erythropoietic capacity]
What is required for Red Blood cell production? (5)
Stem cells- duh
Space in marrow
Growth factors- IL-3, GM-CSF
Iron for Hb molecule production
Cholesterol/ Lipids for membrane
What is the most immature form of a RBC?
Rubriblast- has a dark blue cytoplasm on stain
What is the lifespan of Erythrocytres in domestic species?
Dog- 100 days
Cat- 70 days
[cow/ horse- 150 days]
How are RBC’s eliminated at the end of their lifecycle? (2)
Major route- taken up by phagocytic macrophages and components recycled in the spleen/liver
Minor route- intravascular haemolysis
Anaemia is a reduction in red cell mass, this can mean a decrease in… (4)
Haemoglobin Concentration
Packed cell volume- percentage of cells in a volume of blood
Haematocrit- red cell count and cell volume
Red blood cell concentration
What can we assess in a Packed Cell Volume test? (3)
Buffy coat assessment- leukocytes & thrombocytes
Plasma
Total protein measurement
A decrease in red cell mass can be due to… (2)
Increased loss
Decreased production
When would we classify Anaemia as MILD?
when PCV is 10% below normal- no clinical signs usually found by accident when investigating another pathology
Moderate Anaemia is classified based on…
Mucous membrane pallor, fast bounding pulse,
What are the signs of Severe Anaemia?
PCV in the lower teens and pale, weak presentation
How can we determine if the cells in a RBC sample are normocytic, macrocytic or microcytic?
Look at mean cell volume- based on cell numbers and cell size
Normocytic RBC’s are pathologically seen in…
Why?
mild non regenerative anaemia or acute haemorrhage
because bone marrow release too few macrocytic reticulocytes so most RBCs in the blood are those normocytic normochromic RBCs remaining from prior production
How do Microcytic RBC’s come into existance?
Hb conc determines when division stops- low iron means low Hb means it keep dividing resulting in smaller RBC’s
Give an example of non pathological Microcytic RBC’s?
Akitas- naturally have smaller RBC’s
RBC’s with a thin outer membrane are known as…
Microcytic
Macrocytic RBC’s are usually…
Polychromatophils (immature RBC’s)
Give an example of a non pathological cause of finding Macrocytic blood cells in a sample? (2)
Poodles- naturally have larger RBC’s
In stored blood- cells in the tube progressively swell up so appear Macrocytic
If I find Macrocytic red blood cells in a sample, I can probably guess that the PCV is…
Increased- volume of cells is larger because cells are larger so may affect anaemia classification
How are RBC’s regenerated?
Briefly describe the process.
Kidneys respond to low O2 in blood > release erythropoietin > stimulates bone marrow to increase red cell production
What is the difference between Polychromatophils and Reticulocytes?
Polychromatophils- large, blue cells on stains- young cells containing RNA
Reticulocytes- same cells BUT have been stained with New Methylene Blue so RNA forms an aggregate
Normally we would count Reticulocytes on a blood smear to estimate the RBC count- how does this change in Cats?
Cats reticulocytes are released as aggregate reticulocytes which mature to punctate reticulocytes- we should include either or both when counting them
Using the Reticulocyte %, how can we classify an anaemia as regenerative or non regenerative?
Reticulocyte % X Patient PCV
OR
RBC X Reticulocyte %
Increased loss of RBC’s is indicative of what type of Anaemia?
Give two reasons this occurs…
Regenerative- just means loss is higher than what is being made
Haemolysis or Haemorrhage
What is Melena indicative of and what can we do to confirm this symptom?
GI Bleeding
Take a faecal occult blood test- used to check stool samples for hidden blood
[diet needs to be meat free for 5 days otherwise test will be positive regardless]
How can we differentiate an Internal Haemorrhage from an External Haemorrhage?
HINT- think Iron
Iron levels- In internal, blood remains in the body so iron is fine but external haemorrhages have low iron because the blood is lost fully
What can we do to test for an Immune Mediated Haemolysis?
Coomb’s test- will confirm/ deny anti-RBC antibodies (IgG, IgM, IgA) in the blood
When looked at under a microscope, high proteins in a Red Blood Sample is mistaken for what?
And why?
Mistaken for Agglutination- causes Rouleaux which is RBC’s sticking together as proteins stop RBC repelling each other
What are Ghost cells associated with?
Hb has left the cell- membrane only
Associated with intravascular Haemolysis
Extravascular Haemolysis is usually indicated by the presence of what cell?
Spherocytes- macrophage phagocytoses the RBC
How do parasites cause Anaemia?
Cause Haemolysis by living off the surface of RBC’s and increasing their fragility
Pyriform bodies in a Red Blood cells suggests what?
Haemolysis due to Babesia
What can cause the presence of Heinz Bodies in a blood sample?
Oxidative Damage due to onions, paracetamol, Vitamin K etc.
Apart from Heinz bodies, what other cell type indicates Oxidative Damage and why?
Eccentrocytes- Hb has uneven distribution in the cell due to oxidative damage to the membrane
What inherited conditions can cause Haemolysis and who is predisposed to these conditions?
Pyruvate Kinase deficiency (Beagles and Basenjis)
Phosphofructokinase (English Springers)
Feline Porphyria
If there is decreased production of RBC’s it can be categorised as…
Non regenerative
What systems can involved in a decreased production of RBC’s? (2)
Renal- think Erythropoietin
Endocrine- hypothyroidism & hypoadrenocorticism- cortisol and thyroid hormone effect RBC production
RBC’s in Non Regenerative are usually…
what size/ abundance?
Normocytic & Normochromic- just not being produced lol
Give an example of a disease that causes Non- Regenerative Anaemia?
FeLV- causes depression of erythropoiesis
What causes aplastic anaemia?
Issues with bone marrow meaning all RBC precursors are wiped out e.g. estrogen toxicity (think sertoli tumours), chemotherapy
Give an example of a Regenerative condition that can become Non-regenerative?
Iron deficiency in the long term can become non regenerative
Immune mediated attacks on red cell precursors
What is Erythrocytosis and what can cause it?
Too many RBC’s
Caused by dehydration- less liquid- more concentrated
Splenic Contraction- pushes RBC’s out due to Hypercapnia (too much CO2 in blood) or Hypoxia
How do we store blood samples?
Smears- room temperature
Blood tubes- in fridge
