Lecture 23 - RBC Morphology Flashcards
What is the anatomy of a normal RBC
biconcave disc
reddish color
central pallor
How is Rouleaux different from agglutination
Rouleaux is the stacking of RBCs while Agglutination looks like grape clusters
What species is Rouleaux normal in
Horses
What does Rouleaux indicate is increased
globulin
fibrinogen
What does agglutination indicate
immune-mediated hemolytic anemia
Polychromasia
blueish to purple cells
What correlates with polychromasia
very young reticulocytes
T/F: polychromasia indicate regenerative conditions
TRUE
in what species do we use aggregate reticulocytes? why?
cats; reference intervals are established and they can indicate a more immediate regenerative response
Hypochromasia
increased central pallor with a think rim of hemoglobin
What condition does hypochromasia indicate
iron deficiency
Anisocytosis
variability in cell size
Poikilocytosis
variability in cell shape
Why do RBCs become spherocytes
decreased surface area to volume
loss of membrane
What is the significance of spherocytes (what is the indication)
immune-mediated hemolytic anemia
What do low numbers of spherocytes indicate
zinc deficiency
fragmentation or oxidative hemolytic anemia
Ghost cells
pale, empty RBC membrane (lysed)
What do ghost cells indicate
acute intravascular hemolysis
Intravascular hemolysis
lysis of RBCs within the blood vessel - can lead to pink/red plasma (free hemoglobin)
extravascular hemolysis
destruction of RBCs by macrophages
where do macrophages interact with RBCs
spleen, liver, bone marrow
Eccentrocyte
cell membranes fuse and hemoglobin is pushed to one side giving a ruffled appearance
If an eccentrocyte has lost its membrane it is called a _____
pyknocyte
what do eccentrocytes indicate
oxidative damage
Schistocytes
fragmentations of RBCs due to stress trauma
What can schistocytes help diagnose
- disseminated intravascular coagulation
- hemangiosarcoma
- liver disease
what would help diagnose hepatic lipidosis in cats
schistocytes and acanthocytes
Acanthocytes
cells with irregularly spaced blunted/spade-like projections with central pallor
T/F: acanthocytes are best observed in canine RBCs
TRUE
T/F: Acanthocytes do not indicate fragmentation injury like DIC or hemangiosarcoma
FALSE
What is the difference between acanthocytes and echinocytes
echinocytes have evenly spaced projections and acanthocytes do not
What are two factors that would cause similar artifact as an echinocyte on a blood smear
- slow drying
- old blood
what do echinocytes indicate
dehydration
electrolyte loss
snake envenomation
we would expect to see echinocytes in ______ due to the c3b deficiency that predisposes them to _____
Brittany spaniels; glomerulonephritis
Keratocytes
blister cells
round, clear hole at edge that can rupture
what 3 fragmentation injuries do keratocytes indicate
- mechanical damage
- DIC
- vasculitis
Target cell
bell-shaped cell with extra membrane fold in center
What is the most common indication of target cells
regenerative anemia
Heinz bodies
denatured precipitated hemoglobin
what are the two appearances of Heinz bodies when stained
- small, pale region of cytoplasm
- highlighted methylene blue stain
what kind of damage do heinz bodies indicate
oxidative
Howell-Jolly Bodies
remnant of nuclear material as a single, dark blue peripheral dot
increased number of Howell-Jolly bodies indicates
regenerative anemia
dysfunctional/absent spleen
nucleated RBCs
dark homogenous nucleus with a ruffled periphery
increased nRBCs indicated
premature release (bone marrow) or failure to remove (spleen)
T/F: rare nRBCs are OK
TRUE
Rubricytosis
nRBCs in circulation
“appropriate” rubricytosis is considered
a strongly regenerative anemia
Basophilic stippling
residual aggregates of RNA that appear as basophilic dots throughout cytoplasm
T/F: basophilic stippling is not considered appropriate in any species
FALSE - appropriate in ruminants (regeneration) and carnivores (marked regeneration)
Inappropriate basophilic stippling can be caused by
lead toxicity
dyserythropoiesis
