6. Erythrocytes: Shapes Inclusions/Infective Agents

What is this showing?

anisocytosis

general term for the presence of abnormally shaped erythrocytes

poikilocytosis

In what species is poikilocytosis normal?

goats and young, healthy cattle

What is this showing?

poikilocytosis

What is this showing?

polychromasia

What is this showing?

normal camelid erythrocytes

What is this showing? Is this normal?

poikilocytes in goat blood; yes

What is this showing? Is this normal?

deer blood drepanocytes; yes

What is this showing? Is it normal?

avian erythrocytes; yes

What is this showing? Is this normal?

echinocytes in pig blood; yes because it is normal in pig blood

stacking of red blood cells

rouleaux

How is rouleaux dispersed? What is the process?

using physiological saline solution; wash erythrocytes twice using physiologic saline or add one part blood to 49 parts saline

If the rouleaux adherence disappear grossly, what should be done?

examine microscopically under a coverslip to verify

Cells do not adhere with ________, but continue to adhere in saline with ________.

rouleaux; agglutination

What is this showing?

rouleaux in a dog with hyperglobinemia

What is this showing?

erythrocyte agglutination

What is this showing?

hypochromic appearance due to iron deficiency anemia

What is this showing?

poikilocytes

sickle cells or fusiform or spindle-shaped cells

drepanocytes

In what species are drepanocytes normally present in?

deer family and some angora goats

What causes drepanocytes in vitro?

hemoglobin polymerization with increased oxygen tension and increased pH

What causes drepanocytes in vivo?

hemoglobin polymerizes by low oxygen tension and low pH

crenated cells that have a reversible shape change that are usually an artifact in pigs and can be pathologic with snake envenomation

echinocytes

What is this showing?

echinocytes

What is this showing?

echinocytes in dog with pyruvate kinase deficiency

What else can lead to echinocytes in the blood?

U
P
P
G
N
D
T
F
B
D
L
R
A
I
I

• uremia

• post-transfusion

• PK deficiency in dogs

• glomerulonephritis

• neopplasia

• doxorubican (dogs)

• total body depletion of cations (horses)

• fatty acids

• bile salts

• drugs

• lysophospholipids

• RBC dehydration

• ATP depletion

• increased pH

• increased RBC calcium

abnormally shaped red blood cells characterized by coarse, irregularly distributed projections on their surface

acanthocytes

What is this showing?

acanthocytes

When are acanthocytes most commonly seen in blood?

with liver disease

When else would acanthocytes be seen?

E
H
G
D

• excess cholesterol vs phospholipids

• hemangiosarcoma

• glomerulonephritis

• DIC in dogs

In what other species can you see acanthocytes?

young goats and some young cattle

these cells are most often artifacts in thick blood films

stomatocytes

What does hereditary stomatocytosis cause?

swollen erythrocytes having increased MCV and decreased MCHC

When else can stomatocytes be seen?

with drugs that preferentially bind to the inner half of the lipid bilayer

What is this showing?

stomatocytes

Although the diameter of a spherocyte is ________, there volume is generally ________ to that of disocytes.

less; close

When do disocytes and spherocytes form?

in immune-mediated anemias

In spherocyte formation, what cells have receptors for immunoglobulins and complement on their surface? What will bind to these? What can happen to that cell?

macrophages; erythrocyte with antibodies and or complement bound to their surface; the whole erythrocyte may be phagocytized

When do spherocytes only form?

when only a portion of the membrane is bound and removed (erythrocytes can reseal themselves)

What no longer allows for the formation of discocytes?

the loss of membrane

The MCV is often ________ in immune-mediated hemolytic anemias because of the presence of ________ with high cell volumes.

high; reticulocytes

When can spherocytes be seen?

I
S
Z
E
T
D
R

• IMHA, especially dogs

• snake bites and bee stings

• zinc toxicity

• erythrocyte parasites

• transfusion of stored blood

• dyserythropoiesis in English Springers

• RBC band 3 deficiency in Japanese black cattle

immature reticulocyte

polychromatophilic erythrocyte

What is this cell type?

discocyte

What is this image?

spherocyte

What is this image?

monocyte

What is this image?

PE

What type of cells are these?

schistocytes

What is this showing?

DIC in a dog with heartworms

What erythrocyte changes may be seen in blood smears with fragmentation?

S
K
A

• schistocytes

• keratocytes

• acanthocytes

What cell type is the best evidence for fragmentation? Why?

schistocytes; keratocytes and acanthocytes also occur in other disorders

True or false: A few spherocyte-like cells may also be seen with fragmentation and do not indicate immune-mediated disease in this setting.

true

With DIC, what will accompany the fragmentation?

thrombocytopenia and coagulation disorders

Is there anemia with erythrocyte fragmentation?

usually mild to moderate

What are ways that erythrocyte fragmentation occurs?

M
E
T

• mechanical injury

• endothelial injury

• thermal injury

What are examples of mechanical injury?

D
C
G
C

• disseminated intravascular coagulation (DIC)

• caval syndrome due to heartworms

• glomerulonephritis

• cardiac valvular stenosis

What are examples of endothelial injury?

H
V
S

• hemangiosarcoma (dogs)

• vasculitis

• splenic or hepatic disease

What are examples of thermal injury?

H
S

• heat stroke

• severe burns

What is this showing?

heart failure in dog (fragmentation)

What is this showing?

thermal fragmentation

What are additional causes of fragmented erythrocytes?

S
M
H
C
P

• severe iron deficnecy

• myelofibrosis

• hemophagic histiocytic disorder

• congenital and acquired dyserythropoiesis in dogs

• pyruvate kinase deficiency post-splenectomy in dogs

What is this showing?

canine iron deficiency (fragmentation)

formed due to membrane oxidant damage

eccentrocyte

What are these cells?

eccentrocytes

What is this cell?

pyknocyte

What are these cells?

echinocytes

What are examples of endogenous oxidants? What is the anemia?

K
I
N
U

• ketoacidic diabetes

• inflammation

• neoplasia

• unknown causes

generally mild

What are examples of exogenous oxidants? What is the anemia?

O
G
N
P
V

• onions

• garlic

• NSAID

• propofol

• vitamin K

mild to severe

What are other factors that can lead to eccentrocytes?

A
R
R
I
E

• acetaminophin

• rodenticides

• red maple toxicity in horses

• IV hydrogen peroxide in cows

• enzyme deficiencies (G6PD and GR) in horses

What is this showing?

eccentrocytes

What can cause multiple shape abnormalities?

L
H
G
M
D
C
D
M
C

• liver disorders

• hemangiosarcoma in dogs

• glomerulonephritis

• myeloid neoplasms

• DIC (especially dogs)

• chronic iron deficiency anemia (dogs and ruminants)

• doxorubican toxicity in dogs and cats

• myelofibrosis

• congenital dyserythropoiesis

Which erytrhocytes are generally nucleated?

rubricytes and metarubricytes

When are nucleated erythrocytes generally present in low numbers?

in healthy dogs and cats

When are the three most common reasons to see nucleated erythrocytes?

R
L
H

• regenerative anemias

• lead toxicity

• heat stroke

When else will you see nucleated erythrocytes?

M
S
V
H

• narrow injury or disease

• splenic dysfunction

• various disorders in dogs (cardiovascular, inflammation, trauma, hyperadrenocorticism)

• various disorders in cats (hepatic lipidosis, acute trauma, inflammation)

• hereditary hyserythropoiesis (dogs and cattle)

What are these cells?

nucleated erythrocytes

What is this showing?

lead toxicity in a dog (mild anemia with more nucleated erythrocytes than leukocytes)

Which marrow injuries may not be anemic?

S
E
D
H

• septicemia

• endotoxic shock

• drugs

• heat stroke

What are marrow diseases with nonregenerative anemia?

M
H
I

• myelodysplasia

• hematopoietic neoplasms

• infiltrative disorders

What is this showing?

dog with heat stroke (nucleated erythrocyte)

nuclear remnant that is normal in low numbers in cats and horses

Howell-Jolly body (micronucleus)

What is this cell?

Howell-Jolly body

When are Howell-Jolly body numbers increased?

regenerative anemias

When else may you see Howell-Jolly bodies?

S
G
V
N

• splenectomy

• glucocorticoids

• vincristine therapy in regenerative anemia

• nuclear fragmentation

What is this showing?

dog post-splenectomy (Howell-Jolly bodies)

What is this showing?

dog vincristine treatment (Howell-Jolly bodies)

Up to 5% of heinz bodies is normally present in what species? With what diseases can they be increased?

D
L
H

cats;

• diabetes

• lymphoma

• hyperthyroidism

What can cause the production of Heinz bodies in small animals?

S
A
P
Z
A
M
M
P
M
N
P
H
S

• splenectomy in dogs

• allium species (onion, garlic, leek, chive) ingestion

• propylene glycol in soft-moist foods (cats)

• zinc toxicity in dogs

• acetaminophen

• methylene blue

• methionine

• phenazopyridine

• menadione (vitamin K3

• naphthalene (dog)

• propofol anesthesia in cats

• hydrogen peroxide as an emetic

• skunk musk in dogs

What can cause heinz body formation in large animals?

W
K
R
C
L
S
P
P

• wild and domestic onions in livestock

• kale and other brassica species in ruminants

• red maple leaves in horses and alpacas

• copper toxicity in sheep and goats

• lush winter rye in florida cattle

• selenium-deficient cattle on st. augustine grass

• post-parturient New Zealand cattle on perennial ryegradd

• phenothiazine in horses

diffuse pattern of aggregates of ribosomes and polyribosomes

basophilic strippling

Primarily in ruminants, what is basophilic strippling due to?

regenerative anemia

What is an extremely common reason for basophilic strippling?

lead toxicity

What is this showing?

lead toxicity (basophilic strippling)

What is this showing?

regenerative anemia (basophilic strippling)

What are the infectious agents of erythrocytes?
P
R
M
B
V

• protozoal organisms

• rickettsial organisms

• mycoplasma organisms

• bacterial organisms

• viral organisms

What are examples of protozoal organisms?

B
T
C

• babesia species

• theileria species

• cytauxzoon species

What are examples of rickettsial organisms?

anaplasma species

What are examples of bacterial organisms?

bartonella species

What are examples of viral organisms?

distemper

single celled organisms with a nucleus and cytoplasm

protozoa