Erythrocyte Morphology Changes, Inclusions, and infectious agents

Which species does not have mature nucleated RBCs?

Camelids

What does this picture deptict?

Rouleau/Rouleaux

What RBC morphology abnormality is depicted?

Agglutination

Agglutination cannot be differentiated from normal RBC “clumping“ until what is performed?

• A saline dispersion test

  • If it is normal clumping (Rouleaux), then the RBCs should disperse, but if they remain together then it is agglutination

What is a Poikilocyte?

Any erythrocyte with an abnormal shape (general term)

Acanthocyte

Acanthocytes can appear similar to the RBCs in the image on the right, what is the name for these RBCs?

Crenated Cells

What is the clinical significance of Acanthocytes?

• Hemangiosarcomas, osteosarcomas, lymphoma

• Disorder of nearly any organ in the body

  • GI,musculoskeletal, renal, immune-mediated, etc.

Codocytes

What is the pathogenesis of codocytes?

Excessive membrane relative to HGB content

What is the clinical significance of finding Codocytes?

• Regenerative anemias

• Hepatic, renal, lipid disorders

• Iron Deficiency

Jeuvos Rancheros= cheese (lipids), modelo (liver+renal),

What type of RBC morphological abnormalities could you see if an animal has iron deficiency?***

• Codocytes (60)

• Keratocyte

• Ovalcyte/Eliptocyte

• Schistocyte

Dacrocyte (tear-shaped)

Eccentrocyte

What is the clinical significance of finding Eccentrocytes?

Oxidative Damage

Echinocyte

Keratocyte

What is the clinical significance of finding Keratocytes?

• Vasculitis, intravascular coagulation, endocarditis, hemangiosarcoma

• Feline liver disease, doxorubicin (chemo-antibiotic) toxicosis in cats

• Myelodysplastic disorders

• Iron deficiency

What 2 morphological RBC abnormalities are hallmark indicators of oxidative damage?

1. Eccentrocytes

2. Heinz bodies

Ovalcytes/Eliptocytes

What is the clinical significance of finding Ovalcytes/Eliptocytes?

• Myelofibrosis

• Iron deficiency

• Schistocyte

  • Schizo = cut

What is the clinical significance of finding Shistocyte?

• Hemangiosarcoma

• Intravascular coagulation

• Vasculitis

• Hepatic disease

• Caval syndrome of dirofilaria, endocarditis, heart failure

• Iron deficiency

• Spherocyte

  • Lack central pallor (one solid color)

  • Smaller than RBCs (look similar to microcytes)

What is the clinical significance of finding Spherocytes?

• IMHA (very common)

• Fragmentation hemolysis

• Envenomation

• Zinc toxicosis

IMHA is at the top of your differential list when spherocytes are present

Stomacyte (Eye of sauron)

What is the clinical significance of finding Stomacytes?

• Artifact of thick smears

• Hereditary stomatocytosis

• Amphipathic drugs

• Young erythrocytes

What RBC inclusion is depicted in this image?

Howell-Jolly Bodies

What are Howell-Jolly Bodies?

• Small spherical nuclear remnants (usually a dark purple circle in RBCs)

What is the clinical significance of finding Howell-Jolly Bodies?

• They are associated with regenerative anemias/splenectomy

• Corticosteroid use

• Chemotherapeutics

What RBC inclusion is depicted in this image?

Heinz Bodies

What is the clinical significance of finding Heinz Bodies?

• Overwhelming oxidative damage

  • Multitude of causes

    • Hyperthyroidism, Diabetes mellitus, lymphomas

What are Heinz bodies?

Large aggregate of oxidized/precipitated hemoglobin that are attached to the internal surfaces of erythrocytes

T/F: The presence of some heinz bodies can be normal in cats

True!

What RBC inclusion is depicted in this image?

• Basophilic Stippling

  • This is dispersed ribosomes/polyribiosomes that have aggregated together

• These can be confused wtih Reticulocytes/WBCs

  • Basophilic stippling occurs inside of RBCs, so they will be the same size as other RBCs

1. Siderotic inclusions

2. Howell-Jolly bodies

3. Course basophilic stippling

4. Fine basophillic stippling

Cabot Rings

What are the 2 main erythrocyte infectious agents of North America?

1. Hemotropic Mycoplasma

2. Cytauxzoon felis

What infectious organism of RBCs is this?

• Hemotropic Mycoplasma

  • Gram -ve cocci

  • They attach to the external surfaces of erythrocytes (can fall off)

    • Bc they attach to the exterior, they can also form chains across RBCs

What is the clinical significance of finding Hemotropic Mycoplasma?

Can cause IMHA

Babesia spp.

• Cytauxzoon felis

  • Cignet ring look, very similar to small babesia and can be hard to differentiate

1. Small Babesia spp.

2. Cytauxzoon felis

These can appear very similar, thus making pathologists rely on other methods of confirmation (PCR)