Laboratory Procedures
• Defined:
• A condition of reduced oxygen
carrying capacity of erythrocytes
• May be associated with:
• Decreased production of RBC’s
• Increased destruction of RBC’s
• Inappropriate loss of RBC’s
• A systemic, diagnostic approach to anemia is
necessary and should include:
Good history
Physical exam
Blood film/slide analysis
• Should be aimed at correcting the primary disorder
and supporting the patient.
• IMPORTANT to establish whether the anemia is
• Reticulocyte counts are used to evaluate if the anemia is
regenerative or non-regenerative. WHY???
• Remember that regenerative anemias are usually the
result of hemorrhage or hemolysis and non-regenerative
anemias may involve the bone marrow.
• Remember that regenerative anemias are
usually the result of hemorrhage or hemolysis
and non-regenerative anemias may involve the
bone marrow.
• (Remember Myeloproliferative Disorders???)
Regenerative v. non-regenerative
• Regenerative Anemia:
• Increased reticulocytes, nRBC’s, anisocytosis,
polychromasia and Howell-Jolly bodies.
• Indicates the bone marrow has responded to a demand
for RBC’s by increasing production and releasing into
circulation adequate numbers of immature RBC’s (aka
• Bluish to reddish-blue cytoplasm
• Slightly larger than mature RBC’s (why?)
• When stained with New Methylene Blue = Reticulocytes
Erythrocyte Life
• Stem Cell → Rubriblast→ Prorubricyte → Rubricyte→
Metarubricyte→ Reticulocyte→ RBC
• Metarubricyte- nucleated RBC released in severe
Remember these???
• Irregular net-like structures in polychromatophils when
stained with New Methylene Blue. These structures
are called reticulum.
• Reticulum is irregular clumps of ribosomal RNA and
organelles like mitochondria.
• Most species only have one form of reticulocyte.
Which species has two NORMALLY?
Reticulocytes - continued
• Non-regenerative anemia
• Decreased production of erythrocytes caused by
inadequate production of RBC’s by the bone marrow.
• Canine reticulocytes when stained with New
Methylene Blue are AGGREGATE only.
• Will appear as hyperchromatocytes and as macrocytes
in comparison with normocytes.
Feline Reticulocytes
• Punctate v. Aggregate
• The aggregate reticulocytes mature into the punctate form within 12 –
24 hours.
• Punctate reticulocytes circulate for ~7 – 10 days before all RNA is lost.
• Reticulocyte counts of feline blood should only include the percentage of
aggregate reticulocytes as punctate reticulocytes are not counted since
they don’t reflect the most recent bone marrow response.
e.g. An anemic cat with only punctate reticulocytes is NOT actively
regenerating RBC’s at this time, but has shown some bone marrow regneration
in the last 7 – 10 days.
HemorRhage anemia
• Blood loss anemias are associated with acute,
sub-acute and chronic hemorrhage.
• Hemorrhage – Defined as the escape of blood from a
ruptured vessel. May be external or internal.
• Acute: Extremely sudden onset. Usually follows trauma
or surgical procedures
• Sub-acute: Recent or rather sudden onset. May take
hours-days for clinical signs to appear.
• Chronic: A continuous, constant loss of blood.
Parasitism is most common cause of chronic anemias.
Hemorrhage Anemia - Continued
• Most common cause of hemorrhage related anemia is
• Can also be caused by thrombocytopenia which is
characterized by petechial hemorrhages on ear
pinna(e), mucous membranes, and other non-haired
areas like the abdomen.
• Treatment: Includes steroids, plasma or whole blood
transfusions, and avoidance of trauma.
• Iron is important in the body because it is the main
constituent of hemoglobin.
• Caused by chronic external blood loss.
• Note: severe flea infestations, GI parasites, gastric ulcers and
bleeding tumors can cause significant blood loss over time.
• The iron and hemoglobin lost with this external bleeding
result in the formation of altered RBC’s and decreased life
• Treatment includes correcting the cause of the blood loss
and iron supplements.
Hemolytic Anemia
• Defined: The increased destruction of erythrocytes. (aka,
• Caused by immune components attaching directly or indirectly to
the RBC membrane, altering its structure.
• The body, attempting to regain homeostasis, begins to remove
these altered cells.
• In cats, the most common cause of hemolytic anemia is
Mycoplasma haemofelis, a blood born parasite. Feline Leukemia
can also stimulate an immunohemolytic anemia. Treatment is
aimed at suppressing the immune system w/ steroid therapy.
• In dogs, the most common cause is an underlying inflammatory
• Several commonly seen blood parasites can produce
anemia through hemolysis.
• The parasite attaches to the erythrocyte membrane,
causing an increased destruction of the cells.
• Animals having non-specific signs such as weight loss,
anorexia, fever of unknown origin (FUO), hepatomegaly
and splenomegaly should have blood films examined for
the presence of blood parasites.
anemia/Heinz body anemia
• Drugs can be a source of anemia in small animals.
• Hemoglobin will denature and form Heinz Bodies.
• Cats are considered to be more susceptible to Heinz body
formation due to the structure of their hemoglobin.
• One of the most common Heinz body anemias seen in
the dog is onion toxicity.
• Acetaminophen toxicity can cause anemia in cats and
• Ehrlichia is a rickettsial disease spread by the brown dog
• First recognized in the US in 1963 and gained prominence
because of the large losses among working military dogs
stationed in Vietnam.
• Infection occurs when the organism is transported via the
tick saliva during a blood meal.
• Infection is initially in WBC’s.
• Can be transmitted from infected animal to non-infected
• Infected circulating cells can infect other organs and may result
in platelet consumption and erythrocyte destruction.
Female Tick Laying
Von Willebrand’s
• Canine vWD is the most common inherited blood disorder.
• In healthy dogs, von Willebrand’s factor (vWF) promotes
platelet clumping. Decreasing amounts of the factor causes
a bleeding disorder.
• Has been identified in 54 breeds, with Doberman Pinschers,
German Shepherds, and Labrador Retrievers being the most
• Dogs with this disorder should not be bred and special care
must be taken at times of surgery to ensure hemostasis.
Related flashcards

42 Cards


21 Cards


37 Cards

Create flashcards