Lecture 4 - Morphology of RBC

Question 1

what is the morphology of normal erythrocytes

Answer 1

• biconcave disc
• round cell with central pallor: most prominent in dogs
  exception: camelids have oral erythrocytes
• Anucleate; exception= birds, amphibians, reptiles

Question 2

what are two RBC associations

Answer 2

rouleaux - look like fallen coin stacks, normal in cats and horses, usually reflects increased protein
agglutination - grape like clusters; concern for immune mediated diseases.

Question 3

what is anisocytosis

Answer 3

variability in cell size

Question 4

what poikilocytosis?

Answer 4

variability in cell shape

Question 5

what are macrocytes?

Answer 5

large RBC

Question 6

what are macrocytosis?

Answer 6

increased average RBC

Question 7

what are microcytes

Answer 7

small RBC

Question 8

what are microcytosis?

Answer 8

decreased average RBC size

Question 9

what are all polychromatophils reticulocytes but not all reticulocytes polychromatophils?

Answer 9

polychromatophils are all young cells by definition, they have therefore they are all reticulocytes. however some reticulocytes are in the last stages of maturation and will no longer be polychromatic to the naked eye - ie/ can’t see the blue colour but machine can pick it up

Question 10

what is the difference between aggregate and punctate reticulocytes?

Answer 10

aggregate polychromatophils released in low numbers in healthy dogs 1% and cats 0.4%
punctate reticulocytes - more mature form with only fine reticulum granules. have a long maturation time in cats so up to 10% seen in health

Question 11

basophilic stippling is seen in the regenerative response, what is it?

Answer 11

aggregation of residual RNA
most common in ruminants
can also indicate lead poisoning or dyserythropoiesis

Question 12

howell jolly bodies are often seen in a regenerative response, what are they?

Answer 12

nuclear remnants
seen in low numbers in normal horses, cats.
increased numbers are seen with accelerated erythropoiesis, post splenectomy, hypercotisolaemia
can also indicate dyserthropoiesiss

Question 13

nucleated RBC are often seen in a regenerative response, what are they?

Answer 13

nucleated red blood cells
increased numbers are seen with accelerated erythropoiesis = appropriate metarubricytosis.
increased numbers without region response = inappropriate metarubicytosis = spleen disease, bone marrow injury, lead poisoning, heat stroke

Question 14

what morphological changes appear with IMHA?

Answer 14

agglutination

perfectly round RBC with no central pallor

Question 15

heinz bodies are caused by oxidative damage, what are these?

Answer 15

• round structures protrude from membrane
  denatured, precipitated haemoglobin
  highlighted with NMB stain
  cats are more susceptible –> paracetamol

Question 16

eccentrocytes can be caused by oxidative damage, what are they?

Answer 16

oxidative injury to the erythrocyte membrane, haemoglobin becomes condensed on one side
often seen with heinz bodies
more frequent in dogs

Question 17

what are some causes of oxidative damage?

Answer 17

toxins - garlic, onions (dogs,
zinc (dogs)
paracetamol (cats)
brassica plants (ruminants)
metabolic diseases - hyperthyroidism, diabetes mellitus, lymphoma

Question 18

what are echinocytes?

Answer 18

spiked erythrocytes
REGULAR spaced spikes
often an artefact of slow drying blood sample on smear
pathologic causes: electrolyte depletion, strenuous exercise, uraemia, glomerulonephritis

Question 19

what are codocytes? also known as target cells

Answer 19

increased cell membrane to haemoglobin ratio
seen in regenerative response, liver disease, lipid metabolism disorders
central pallor byt Hb in the middle, usually immature floppy membrane in regenerative response

Question 20

what are acanthocytes?

Answer 20

IRREGULAR membrane projections

causes: splenic disease, liver disease, iron deficiency, intravascular damage (DIC - sheer injury)

Question 21

what are schistocytes?

Answer 21

cell fragments
causes - intravascular damage due to DIC, haemangiosarcomas, vasculitis, endocarditis, iron deficiency (fragility of cell)

Question 22

what are ovalocytes?

Answer 22

oval shaped RBC
associated with bone marrow disease, hepatic disease eg/ hepatic lipidosis, PSS
NORMAL In CAMELIDS

Question 23

what are keratocytes and blister cells?

Answer 23

indicate microvascular antipathy/sheer injury. associated with DIC, iron deficiency, haemangiosarcoma, liver disease, marrow disease
keratocyte is when the blister has popped