Interpretation of leukocyte responses in disease Flashcards
Leukemia is
neoplastic cells in the blood and/or bone marrow
Leukemoid response or reaction is
can easily be mistaken for leukemia
Leukemoid response or reaction is characterized by
Marked leukocytosis (>50.0 x 10⁹WBC/L)
Usually due to an inflammatory response
Pancytopenia means
refers to a decrease in the number of all blood cell types
Left shift means
increased numbers of immature neutrophils in the blood
Degenerative left shift means
normal to decreased numbers of mature neutrophils with equal or higher numbers of immature neutrophils BAD
Leukopenia looks like
A decrease in white blood cell numbers
Leukopenia may be balanced with a decrease in the number of all cellular elements, or it may be confined to one cellular element
Nursing care and great nutrition are important to prevent secondary infections & for bone marrow function
Common causes of leukopenia
Viral infections
Overwhelming bacterial infections
Anaphylactic shock & endotoxic shock
Certain antibiotics
Chemotherapeutic drugs
Some analgesics
Lead, mercury, antihistamines, & cortisone products
A cachectic state (usually due to anorexia)
Leukocytosis looks like and is due to
An increase in white blood cells
Usually due to a rise in the number of circulating neutrophils
Commonly occurs due to a physiological cause (as opposed to a pathological one)
Physiological causes of leukocytosis
EXERCISE (more common in cats & horses)
STRESS (more common in dogs)
TRAUMA
STEROID THERAPY
CHRONIC ILLNESS
Due to an increase in other cell types
Stress response results in WBC
WBC changes that occur in response to stress, chronic illness, exercise or steroid supplementation
The absence of a stress response in an animal that is sick is significant
What will you see in a cat and dogs blood smear from a stress response
you will see a mature neutrophilia, monocytosis, lymphopenia, possible eosinopenia
What will you see in a cattles blood smear from a stress response
reversal of neutrophil to lymphocyte ratio even if both are still within reference limits
What will you see in a horses blood smear from a stress response
mature neutrophilia and lymphopenia*
Pathological Causes of Leukocytosis
Systemic or localized infections–can cause marked neutrophilia (in dogs also monocytosis) with a possible left shift
Mastitis, peritonitis & metritis
Inflammation
Acute hemorrhage –especially if it is into a body cavityt
Sudden lyses of erythrocytest
Some toxinst
Neoplasia
Leukemia– may produce an increase in bizarre, atypical cell types and a severe left shift
t These cases usually result in a neutrophilia with NO left shift, may be followed by a monocytosis
Leukocytosis is and related to
The total leukocyte response in an individual is directly related to the patient’s susceptibility to an infection, it’s immune status, and it’s general health
Debilitated animals may fail to show the expected response
The bone marrow may be affected by the underlying condition
Left shift refers to
Refers to an increased concentration of immature neutrophils in the peripheral blood
Band neutrophils are the first immature cells to appear
Metamyelocytes or earlier immature forms may also be seen
Can accompany either a neutrophilia or neutropenia
What does a left shift look like
Orderly classification-there should be fewer immature cells than mature neutrophils
Left shifts are described as
Left shifts are usually described as to the degree of the shift
They are termed slight or mild if shifted to the band neutrophil stage
Moderate if shifted to the metamyelocyte stage
Marked or severe if shifted to the myelocyte or promyelocyte stage
Regenerative Left Shift looks like
A leukocytosis due to a neutrophilia & the appearance of immature neutrophils that do not out-number the mature neutrophils → the bone marrow is responding to the inflammatory stimulus
Degenerative Left Shift looks like
The total WBC count is often normal, but it can also be above or below the normal range
The immature neutrophils out-number the mature ones → the bone marrow is no longer keeping up to the demands of the body
Usually indicates a poor prognosis
A DEGENERATIVE left shift accompanying a low total WBC count calls for a guarded prognosis
Regenerative to a Degenerative Left Shift
It will take some time to go from a regenerative to a degenerative shift
At first the body will be able to maintain a leukocytosis
In time, the total WBC count will fall & a leukopenia develops
What happens to the bone marrow with a left shift
The bone marrow’s ability to respond is measured by the total leukocyte count
The intensity of the response is measured by the extent of the left shift
Leukemoid Response/Reaction
This is a condition that is easily mistaken for a leukemia
The leukemoid response & leukemia can only be differentiated via a bone marrow exam
With both conditions, the peripheral blood shows an increased total count with a severe left shift
A leukemoid response is usually associated with severe inflammation & infection such as a pyometra, hepatic abscesses, etc
A leukemoid response is likely treatable while leukemia has a grave prognosis
How to tell its a leukemoid response
Characterized by a severe leukocytosis (more than 50.0–100.0 x 10⁹WBC/L)
Most are mature neutrophils
Marked left shift showing myelocytes and metamyelocytes
Cells show toxic granulation, Döhle bodies and increased vacuoles
Bone Marrow Function
In young animals, the bone marrow is very hematopoietically active
As the animal matures the marrow activity decreases & fat cells take up more marrow volume
There are two types of marrow, they differ histologically
The active marrow is called RED MARROW
The other is called YELLOW MARROW
What happens to bone marrow with blood loss
If there is a sudden massive blood loss or hemolytic destruction of red cells, it takes about 48 hours for the yellow marrow to begin the conversion into red marrow
-It then becomes very active to replace the lost cells
During chronic blood loss, this conversion occurs more slowly
Bone marrow evaluation is used for what
Used to diagnose conditions or provide a prognosis for a condition
Findings on a blood smear analysis are used to determine whether or not a bone marrow evaluation is required
What in a blood smear will tell you a bone marrow evaluation needs to be done
Persistent unexplained pancytopenia, neutropenia, or thrombocytopenia, and non-regenerative anemia
Abnormal circulating cells
Unexplained presence of immature cells on a smear
How to preform a bone marrow evaluation
Contraindicated in patients with clotting disorders
It is a painful procedure–the patient needs to be anesthetized or heavily sedated with a local anesthetic at a minimum
Requires aseptic technique
Bone marrow aspiration site for dogs
Dogs: proximal end of the femur at the trochanteric fossa, the iliac crest or the proximal humerus
Bone marrow aspiration sites for cats
Cats: trochanteric fossa or proximal humerus
Bone marrow aspiration sites for LA
Horses & cattle: sternum, ribs or ilium
How to preform a bone marrow evaluation
An RVT should screen the slide to make sure it is of diagnostic quality before it is submitted to the lab
Ensure that cells are present and intact
Bone marrow evaluation must be accompanied with a CBC*
The CBC should be taken at the same time as the bone marrow aspirate
The smear should be evaluated on low-power objective to evaluate the adequacy of the smear and the degree of cellularity
What should a bone marrow evaluation look like
Juveniles or Young animals should have 75% nucleated cells to 25% fat
Adults should have a 50% nucleated cells to 50% fat
Geriatric animals should have a 25% ratio of nucleated cells to 75% fat
Cells Within the Bone Marrow
mmature RBCs
Mature RBCs
Immature granulocytes
Mature neutrophils, eosinophils and basophils
Immature platelets
Macrophages, lymphocytes, plasma cells, mast cells, osteoblasts and osteoclasts
Microorganisms in bone marrow
Occasionally found on bone marrow aspirates
Bacteria are a very rare finding
What are you likly to see in bone marrow that is bad
More likely to see:
Histoplasma capsulatum
Toxoplasma gondii
Leishmania donovani
Ehrlichia species
Mycoplasma haemofelis
Babesia species
