Erythrocyte Morphology

Question 1

A low HCT and high MCV indicates what?

Answer 1

Macrocytic anemia (regenerative)

Question 2

A low HCT and low MCV indicates what?

Answer 2

Microcytic anemia (Fe++ deficiency)

Question 3

Blood loss, blood destruction, or recovering bone marrow after dysfunction would cause what type of cell to appear on a blood film?

Answer 3

Polychromatophils

Question 4

What is this Llama suffering from?

Answer 4

Microcytic anemia

*Any loss of color in camelid RBCs is considered increased pallor and would indicate Fe++ deficiency

Question 5

T/F: These erythroytes are exhibiting increased central pallor.

Answer 5

FALSE

These RBCs have a fairly thick ring of hemoglobin around the edge. They are bowl shaped RBCs and do not indicate true hypochromasia.

Question 6

What happes to the RBC morphology when a blood film is dried too slowly?

Answer 6

Crenation: will see echinocytes on the film.

Question 7

What can cause spiculated RBCs (echinocytes) in vivo?

Answer 7

Electrolyte imbalances

Non-specific diseases

Rattlesnake bites

Question 8

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?

Answer 8

Type 3 echinocytes

Ask the owner if the dog could have been bit by a rattlesnake.

Question 9

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?

Answer 9

Humans with liver disease

Cats with hepatic lipidosis

Dogs with hemangiosarcoma (fragmented RBCs)

Question 10

Examine the blood film. What kind of abnormal cells are featured and what is on your differentials list?

Answer 10

Schistocytes (fragmented RBCs)

DDx: intravascular trauma (DIC, vascular tumors), or Fe++ deficiency anemia

Question 11

On this blood film of a cat with Fe++ deficiency anemia, what cell abnormalities can you see?

Answer 11

Numerous keratocytes (RBCs with long spicules formed by breaking open of “blisters”)

Increased number and size of platelets (immature)

Question 12

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?

Answer 12

Spherocytes (ball shaped RBCs)

These cells indicate Immune Mediated Hemolytic Anemia in most cases.

Question 13

In addition to anemia and spherocyte formation, what other property of a blood film will indicate IMHA?

Answer 13

Agglutination

Question 14

What is the most common cause of hemolytic anemia in dogs?

Answer 14

IMHA

Question 15

By what mechanism is a spherocyte formed?

Answer 15

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.

Question 16

In ______ hemolysis, macrophages eat RBCs.

Answer 16

extravascular

Question 17

In ______ hemolysis, holes are punched in the membranes of RBCs by the MAC.

Answer 17

intravascular

Question 18

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?

Answer 18

Eccentrocytes

The RBC changes in this dog are likely due to ingestion of onions, which causes oxidative damage to the cells.

Question 19

What causes torocytes and are they clinically significant?

Answer 19

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.

Question 20

Target cells, which have an area of HG within the central pallor, can be found in dogs with what problem?

Answer 20

High cholesterol

*but also found in normal dogs

Question 21

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?

Answer 21

No, these are stomatocytes and are usually an insignificant finding. They are also hereditary in Alaskan Malamutes, Miniature Schnauzers, and Drentse Partrijshond.

Question 22

A blood smear from a sick cat shows the following RBC morphology changes. What is on your differential?

Answer 22

These are Heinz bodies caused by oxidative damage.

DDx: Acetaminophen

Propylene Glycol (in canned food)

Illness (lymphoma, hyperthyroidism, diabetes)

Question 23

Heinz bodies on a dog’s blood smear can indicate ingestion of what items?

Answer 23

Onions (all species)

Cephalosporins

Pennies (zinc toxicosis)

Question 24

What can cause Heinz bodies in horses?

Answer 24

Phenothiazine

Wilted red maple leaves

Question 25

What can cause Heinz bodies in cattle?

Answer 25

Kale

Onions

Question 26

In what species would you expect to see Heinz bodies with copper toxicity?

Answer 26

Sheep

Question 27

What erythrocyte change would you expect to see in small animals with very regenerative anemia, or in larger amounts, lead poisoning?

Answer 27

Basophilic stippling

Question 28

T/F: Basophilic stippling in ruminants, like in small animals, is indicative of lead poisining?

Answer 28

FALSE

Normal in ruminants

Question 29

Nucleated RBCs and Howell-Jolly bodies are seen in what conditions?

Answer 29

Regenerative anemia

Non-functioning spleens or splenectomies

Increased corticosteroids

Question 30

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?

Answer 30

Lead poisoning

Question 31

This is the most common RBC parasite in small animal practice:

Answer 31

Mycoplasma haemofelis

Question 32

In a dog with M. haemophilus infection, you note multiple ghost cells. What are these cells and how are they created?

Answer 32

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.

Question 33

A blood smear on a previously splenectomized dog looks like this. What is the causative agent?

Answer 33

Mycoplasma haemocanis

Question 34

From a cat’s blood film. What dat?

Answer 34

Cytauxzoon felis

Question 35

Protozoan parasites Babesia canis and Babesia gibsoni infect the erythrocytes of dogs. What is the mode of transmission?

Answer 35

Ticks

Question 36

These parasites of cattle fall off very easily and can be mistaken for stain sediment on a blood film.

Answer 36

Mycoplasma wenyoni

Question 37

These parasites are usually found around the margins of RBCs in cattle.

Answer 37

Anaplasma marginale

Question 38

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?

Answer 38

Distemper virus

Question 39

Rouleaux is a normal finding in equine blood smears, but suggests what in small animal samples?

Answer 39

Increased globulin

*The most common cause of increased globulin in dogs on St Kitts is Ehrlichia

Question 40

What change in erythrocyte morphology occurs when IgM Ab attach to RBCs (as with IMHA)?

Answer 40

Agglutination

Question 41

How can you differentiate rouleaux from agglutination?

Answer 41

Saline agglutination test. When saline is added to the sample, cells in rouleaux will disperse, but agglutinated cells will stay together.