Erythrocyte Morphology Flashcards
A low HCT and high MCV indicates what?
Macrocytic anemia (regenerative)
A low HCT and low MCV indicates what?
Microcytic anemia (Fe++ deficiency)
Blood loss, blood destruction, or recovering bone marrow after dysfunction would cause what type of cell to appear on a blood film?
Polychromatophils
What is this Llama suffering from?
Microcytic anemia
*Any loss of color in camelid RBCs is considered increased pallor and would indicate Fe++ deficiency
T/F: These erythroytes are exhibiting increased central pallor.
FALSE
These RBCs have a fairly thick ring of hemoglobin around the edge. They are bowl shaped RBCs and do not indicate true hypochromasia.
What happes to the RBC morphology when a blood film is dried too slowly?
Crenation: will see echinocytes on the film.
What can cause spiculated RBCs (echinocytes) in vivo?
Electrolyte imbalances
Non-specific diseases
Rattlesnake bites
A Golden Retriever comes into your clinic on emergency during a family camping trip. A blood smear shows that all RBCs have very slender spicules and loss of central pallor. Polychromatophils are not affected. What type of echinocytes are these and what information from dog’s recent history would help to rule out IMHA?
Type 3 echinocytes
Ask the owner if the dog could have been bit by a rattlesnake.
Acanthocytes are RBCs with a few unevenly distributed projections, a result of changes in lipid concentrations in the cell membrane. What diseases commonly cause this?
Humans with liver disease
Cats with hepatic lipidosis
Dogs with hemangiosarcoma (fragmented RBCs)
Examine the blood film. What kind of abnormal cells are featured and what is on your differentials list?
Schistocytes (fragmented RBCs)
DDx: intravascular trauma (DIC, vascular tumors), or Fe++ deficiency anemia
On this blood film of a cat with Fe++ deficiency anemia, what cell abnormalities can you see?
Numerous keratocytes (RBCs with long spicules formed by breaking open of “blisters”)
Increased number and size of platelets (immature)
A blood film on a dog shows these RBCs that lack central pallor and APPEAR to be smaller, although the MCV is normal. What kind of cells are these and what disease do they commonly indicate?
Spherocytes (ball shaped RBCs)
These cells indicate Immune Mediated Hemolytic Anemia in most cases.
In addition to anemia and spherocyte formation, what other property of a blood film will indicate IMHA?
Agglutination
What is the most common cause of hemolytic anemia in dogs?
IMHA
By what mechanism is a spherocyte formed?
Ag on RBC is no longer recognized as “self” and a macrophage bites off part of the membrane, decreasing the surface area, but leaving the interior volume intact, thereby forming the RBC into a ball.
In ______ hemolysis, macrophages eat RBCs.
extravascular
In ______ hemolysis, holes are punched in the membranes of RBCs by the MAC.
intravascular
A sick dog comes into your clinic and it appears as though the hemoglobin in the RBCs has shifted to one side. What are these cells called and how did this dog likely become ill?
Eccentrocytes
The RBC changes in this dog are likely due to ingestion of onions, which causes oxidative damage to the cells.
What causes torocytes and are they clinically significant?
Torocytes (bowl shaped RBCs) are caused by folding of the cells as they pass through capillaries. Some cells don’t unfold and become torocytes. They are of little diagnostic significance.
Target cells, which have an area of HG within the central pallor, can be found in dogs with what problem?
High cholesterol
*but also found in normal dogs
You are sent a blood smear from an Alaskan Malamute and you note a few red cells in which the central pallor is mouth-like instead of round. Should the referring veterinarian be worried about the presence of these cells?
No, these are stomatocytes and are usually an insignificant finding. They are also hereditary in Alaskan Malamutes, Miniature Schnauzers, and Drentse Partrijshond.
A blood smear from a sick cat shows the following RBC morphology changes. What is on your differential?
These are Heinz bodies caused by oxidative damage.
DDx: Acetaminophen
Propylene Glycol (in canned food)
Illness (lymphoma, hyperthyroidism, diabetes)
Heinz bodies on a dog’s blood smear can indicate ingestion of what items?
Onions (all species)
Cephalosporins
Pennies (zinc toxicosis)
What can cause Heinz bodies in horses?
Phenothiazine
Wilted red maple leaves
What can cause Heinz bodies in cattle?
Kale
Onions
In what species would you expect to see Heinz bodies with copper toxicity?
Sheep
What erythrocyte change would you expect to see in small animals with very regenerative anemia, or in larger amounts, lead poisoning?
Basophilic stippling
T/F: Basophilic stippling in ruminants, like in small animals, is indicative of lead poisining?
FALSE
Normal in ruminants
Nucleated RBCs and Howell-Jolly bodies are seen in what conditions?
Regenerative anemia
Non-functioning spleens or splenectomies
Increased corticosteroids
A blood smear on a patient shows moderate, regenerative anemia with a large and disproportionate amount of Howell-Jolly bodies and nucleated RBCs. What do you suspect is causing these changes in morphology?
Lead poisoning
This is the most common RBC parasite in small animal practice:
Mycoplasma haemofelis
In a dog with M. haemophilus infection, you note multiple ghost cells. What are these cells and how are they created?
RBCs that have no HG in them.
Ghost cells result in these infections because the parasite latches onto the cell membrane and is antigenic, causing intravascular hemolysis.
A blood smear on a previously splenectomized dog looks like this. What is the causative agent?
Mycoplasma haemocanis
From a cat’s blood film. What dat?
Cytauxzoon felis
Protozoan parasites Babesia canis and Babesia gibsoni infect the erythrocytes of dogs. What is the mode of transmission?
Ticks
These parasites of cattle fall off very easily and can be mistaken for stain sediment on a blood film.
Mycoplasma wenyoni
These parasites are usually found around the margins of RBCs in cattle.
Anaplasma marginale
A client brings her dog in with a recent history of purulent nasal discharge and anorexia. You do a blood smear with a diff-quick stain and see circular inclusions in the erythrocytes. What is the causative agent?
Distemper virus
Rouleaux is a normal finding in equine blood smears, but suggests what in small animal samples?
Increased globulin
*The most common cause of increased globulin in dogs on St Kitts is Ehrlichia
What change in erythrocyte morphology occurs when IgM Ab attach to RBCs (as with IMHA)?
Agglutination
How can you differentiate rouleaux from agglutination?
Saline agglutination test. When saline is added to the sample, cells in rouleaux will disperse, but agglutinated cells will stay together.
