Hematology: WBC Abnormalities and Platelet Review

Flashcards covering WBC abnormalities (hypersegmentation, hyposegmentation, toxic changes), leukogram patterns (Fear, Stress, Inflammatory), and platelet abnormalities (size variations and counts).

Nuclear hypersegmentation

The presence of $\ge 5$ nuclear lobes in neutrophils, representing a normal progression of nuclear maturation and indicating an "old" neutrophil that has been in circulation longer than usual.

Pelger-Huet anomaly

A hereditary defect resulting in nuclear hyposegmentation, where granulocytes (neutrophils, eosinophils, and basophils) have nuclei with fewer nuclear lobes than normal.

Toxic changes

Visual differences in neutrophil cytoplasm that occur in response to inflammation, infection, or toxicity elsewhere in the body, indicating neutrophils are being produced at an accelerated rate.

Vacuolation ("foaminess")

The formation of membrane-bound sacs of fluid called vacuoles in the cytoplasm, which may appear as small, circular, white bubble-like structures.

Cytoplasmic basophilia

Increased purple-staining of the cytoplasm when stained with basic dyes, often containing intensely staining granules referred to as toxic granulation.

Dohle bodies

Small blue-grey areas in the neutrophil cytoplasm that represent aggregations of endoplasmic reticulum.

Cytoplasmic inclusions

A general term for abnormal collections of structures in neutrophil cytoplasm, such as infectious agents (Ehrlichia, Anaplsma, Histoplasma, Mycobacterium) or structures like Dohle bodies.

Neutrophil giantism

A condition where the neutrophil itself appears larger than other typical neutrophils.

Left shift

An increased concentration of immature neutrophils (usually band cells) in the blood, indicating an increased demand for neutrophils and a temporary depletion of the storage pool.

Reactive lymphocytes (immunocytes)

B-lymphocytes or plasma cells with increased cytoplasmic basophilia and a larger, more convoluted nucleus, usually indicative of antigenic stimulation from infection or vaccination.

Smudge cells (basket cells)

Degenerative leukocytes that have ruptured; high numbers can be associated with leukemia or occur as an artifact if blood is held in a collection tube too long.

Fear/Excitement induced Leukogram

A pattern with fast onset (minutes) caused by Epinephrine/SNS stimulation, characterized by increased lymphocytes, monocytes, and neutrophils.

Stress (corticosteroid) induced Leukogram

A pattern with slow onset (hours to days) caused by illness or trauma, characterized by increased neutrophils and monocytes, and decreased eosinophils and lymphocytes.

Acute inflammatory or infectious leukogram

A profile similar to a corticosteroid induced leukogram but with the addition of a neutrophilic left shift (bands) and "toxic changes" to neutrophils.

Normal platelet concentration (on film)

At least $10-30$ platelets/oil immersion field ($1000 \times$ magnification), assuming no clumping at the feathered edges.

Normal platelet size

Platelets should be smaller than RBCs, typically measuring $\frac{1}{4}$ to $\frac{1}{2}$ the size of the RBCs.

Microplatelets

Platelets smaller than normal that may be observed with iron-deficiency anemia, immune-mediated disease, or bone marrow diseases.

Macroplatelets

Platelets about the same size as RBCs that enter circulation when production and release are accelerated at the bone marrow.

Megathrombocytes

Platelets larger than the diameter of RBCs, which can sometimes indicate bone marrow disease.

Thrombocytopenic

A condition describing an animal with lower than normal platelet counts.

Thrombocytosis

A condition describing an animal with greater than normal platelet counts.

Platelet clumping

The formation of groups of platelets after collection; this can cause automated analyzers to report falsely low concentrations.