Introduction to Haematology 22.09.2014 Flashcards
What would be the indications to look for erythrocytes, leukocytes, platelets and plasma on a haematology test?
- Erythrocytes - anaemia, erythrocytosis (i.e. increased)
- Leukocytes - inflammatory conditions, neoplastic conditiions, chemotheraphy
- Platelets - bleeding disorders, DIC
- Plasma - colour (normally colourless)
How do you determine total protein?
Run a PCV, the put plasma into a refractometer to determine plasma protein
Why would a stressed animal show a different PCV to normal?
The spleen releases stored RBCs when the animal is stressed.
What variables are looked at in relation to RBCs? (7)
RBC concentration, HGB, HCT, MCV, MCH, MCHC, RDW (red cell distribution width)
How is anaemia classified? (4) Why is it done these ways?
- ) Mild, moderate, severe
- ) MCV - normocytic, microcytic, macrocytic
- ) MCHC - normochromic, hypochromic, (hyperchromic)
- ) Regenerative vs. non-regenerative.
Helps narrow cause
Examples of when you might see a normocytic anaemia.
Often associated with mild non-regenerative anaemia, acute haemorrhage etc,
When might you see microcytic anaemia? (3) Dog breed predisposition? (1)
Iron deficiency (allows an extra RBC division to ensure red cell haemoglobin concentration), PSS, hepatic failures. Akitas.
When might you see a macrocytic anaemia? Dog breed predisposition (1)
In regeneration.
Some poodles.
When might you sees a normo- or hypochromic anaemia?
Decreased iron/poor iron incorporation (with microcytosis)
Why isn’t a hyperchromic anaemia not possible?
RBCs are haemolysed.
2 reasons for regenerative anaemia
Haemolysis or haemorrhage
Most common causes of non-regenerative anaemia (3)
- Anaemia of inflammatory/chronic disease (mild, v. common)
- CRF (severe)
- Decreased production in marrow
Differentiate polychromataphils and reticulocytes.
Same cells just different staining:
- Polychromatophils: Diff-quik or giemsa stain, young cells containing rRNA show up as larger, bluer cells
- Reticulocytes: same cells stained with New Methylene Blue and the RNA precipitates from aggregates (reticulum)
How are cat reticulocytes different?
They are released as aggregate reticulocytes and mature to punctate retics over time. Retic. counts should record either aggregate or both.
How do you differentiate between regenerative and non-regenerative aneamias? What are (ab)normal values?
Using the reticulocyte % (1000 RBCs counted, retics expressed as a percentage of this). Corrected reticulocyte % (same number of reticulocytes willt ake up more of a percentage in a very anaemic animal therefore calculate ritc %*(patient PCV/normal PCV).
NORMAL= 45% in dogs, 35% in cats
If regenerative>1% corrected (dog), >0.4% (cat)
Absolute reticulocyte concentration may be better:
RBC conc*retic%
What are the signs of regenerative anaemia on a blood smear? (7)
polychromasia, anisocytosis, macrocytosis, nRBCs, Howell-Jolly bodies, codocytosis, basophilic staining.
What are different aspects of RBC morphology? (5)
- Spherocytes, ghost cells
- Hypochromasia/leptocytosis
- Shear products (keratocytes, shistocytes, acanthocytes)
- Oxidative damage (Heinz bodies, eccentrocytes, pyknocytes)
- Organisms
Which WBCs are considered in a CBC?
Neutrophils, lymphocytes, monocytes, eosinophils, basophils
How can stress affect neutrophils?
Neutrophils normally circulate in the blood for approximately 6 hours but stress can cause neutrophils to move back from the tissue into the blood.
What must be considered when looking at neutrophilia or neutropenia?
Ration of ProNP, MatNP and SNP. (i.e. look for left shift and toxicity)
How is left shift classified?
REGENERATIVE: neutrophilia, segmented>bands
DEGENERATIVE: neutropenia, bands>segemented
In between?
Which two ways can leukaemia be defined?
Acute/chronic or lymphoid/myeloid (i.e. lymphocytes vs neutrophils)
How does clumping affect platelets?
It is a very common problem. It causes a decrease in platelet count/concentration as platelets aren’t evenly distributed in the fluid.
Describe acute leukaemias
Blast cells in circulation (difficult to ID cell of origin). Much more likely to be lymphoid. ALL (acute lymphoid leukaemia) versus stage 5 lymphoma. If signs of segmentation = myeloid or myelomonocytic. Do immunophenotyping using a flow cytometer.
Describe chronic leukaemias.
CLL = chronic lymphoid leukaemia; lymphocytes appear small and mature, persistant high numbers CML = chronic myeloid leukaemia, neutrophils appear normal, persistant high numbers.
How do you do a manual estimate of WBC numbers?
Average platelet number per 10 field, multiply by 15-20*10^9/L. Ensure you have a monolayer!
