Leukocyte CBC Patterns pt 2

Eosinophilia

increase in eosinophils

Three causes of eosinophilia

1.) worms

2.) wheezes

3.) weird diseases

Parasite causes of eosinophilia:

-heartworms

-tissue nematodes, trematodes, protozoa

-ectoparasites

eosinophilia is usually not seen with parasitic organisms that infect...

blood cells (Mycoplasma, Bebsia, Hepatozoon)

"wheezes" causes of eosinophilia

-allergic disorders

-asthma

-anaphylaxis

"weird diseases" causes of eosinophilia

-adrenal cortical insufficiency (hypoadrenocorticism or Addison's disease)

-fungal infections

-Neoplasms

Why does Addison's disease cause eosinophilia?

excess cortisol in the blood usually leads to decreased eosinophils; if adrenal glands are not functioning, cortisol is low, and eosinophils will be high

True or false: not every patient with Addison's disease will have eosinophilia

true; inconsistent finding or can be mild

What other CBC finding can be indicative of Addison's disease?

lack of a stress leukogram; any animal that is sick should have a stress leukogram

Why can neoplasia lead to eosinphilia?

neoplasms release cytokines which stimulates eosinophils to be released into the bloodstream

Hypereosinophilic syndrome

Marked eosinophilia of undetermined cause (idiopathic)

What causes Hypereosinophilic syndrome?

there is an overproduction in the bone marrow of unknown cause

Hypereosinophilic syndrome is a diagnosis of _________

exclusion; need to rule out other diseases first before this diagnosis

Two other causes of eosinophilia to rule out before diagnosing Hypereosinophilic syndrome:

-leukemia

-"worms, wheezes, other weird diseases"

How can leukemia be ruled out to diagnose Hypereosinophilic syndrome?

if there are no early precursor cells in the blood on a blood smear, or if there are no other cell lines are decreased, this means it is not leukemia

Characteristics of eosinophils for Hypereosinophilic syndrome

mature, segmented, and normal in morphology

To be diagnosed with Hypereosinophilic syndrome, an animal must have eosinophilia for greater than _____ months

6 months

Hypereosinophilic syndrome can also cause ________ damage. Why?

organ; eosinophils will infiltrate the tissues and release granules with enzymes, causing organ damage

Eosinopenia

decrease in eosinophils

Eosinopenia can be _________ to detect. Why?

difficult; the lower reference interval can be zero

Eosinopenia is usually of __________ clinical significance

limited

Causes of eosinopenia

-increased corticosteroids

-increased margination, tissue sequestration

-decreased marrow release and production

Basophilia

increase in basophils

Basophilia if often concurrent with...

eosinophilia; rare finding!

Causes of basophilia

diseases that increase IgE production!

-heartworm disease

-allergic reactions

-neoplasia

Basopenia

decrease in basophils; not clinically significant!

Lymphocytosis

increase in lymphocytes

Five types of causes of lymphocytosis

1.) physiologic

2.) age

3.) chronic inflammatory lymphocytosis

4.) Addison's disease

5.) neoplasia

Physiologic cause of lymphocytosis

caused by epinephrine; exercise, excitement, fear, and pain can cause endogenous release of epinephrine

Why does epinephrine cause a lymphocytois?

epinephrine causes increased blood flow, which causes a shift of lymphocytes from marginal to circulating pool in the blood

Physiologic causes of lymphocytosis are _________

transient (will go away after a couple of hours)

Lymphocytosis in young animals

occurs since young animals are often being vaccinated and antigenic stimulation is occuring

Chronic inflammatory lymphocytosis is due to...

Increased lymphopoiesis (lymphocyte generation) in response to chronic antigenic or cytokine stimulation

What type of lymphocytes might be present on a blood smear for a chronic inflammatory lymphocytosis?

reactive lymphocytes

Causes of Chronic inflammatory lymphocytosis

-certain bacterial infections (Ehrlichia canis)

-fungi

-parasites

-viruses

-immune mediated disease

Lymphocytosis due to chronic inflammation often occurs with...

neutrophilia, +/- left shift, monocytosis

Bovine Leukemia Virus causes what finding on CBC?

persistent lymphocytosis

Why does Bovine Leukemia Virus cause persistent lymphocytosis?

due to decreased apoptosis of virus- infected B lymphocytes (they live longer) and proliferation of non-infected B lymphocytes

Lymphocytosis: Addison's disease

adrenal glands are deceased and not making cortisol, so lymphocytes will increase

Addison's disease causes the opposite of "_____"

LEMN

Always think about Addison's in a sick dog with lymphocytosis because...

stress from being sick should cause a lymphopenia

Lymphoid neoplasia and lymphocytosis

Lymphoproliferative neoplasia can cause lymphocytosis

examples of Lymphoid neoplasia

-lymphoma (BLV, FeLV)

-lymphoid leukemia

Lymphopenia

decrease in blood lymphocytes

Four causes of lymphopenia:

1.) Corticosteroids

2.) acute inflammation

3.) depletion/loss

4.) decreased production

What is the most common cause of lymphopenia?

Corticosteroids

Why do corticosteroids cause lymphopenia (2)?

1.) corticosteroids will cause lymphocytes to move out of the bloodstream and into the lymphoid tissues

2.) they also directly decrease proliferation of lymphocytes

Lymphopenia due to Acute Inflammation is caused by...

acute bacteria infections with +/- endotoxemia

Why do bacterial infections with endotoxemia cause lymphopenia (3)?

1.) bacteria will migrate to inflamed tissues and lymphoid tissues, which causes lymphocytes remain in lymphoid tissues to help fight the infection

2.) bacteria will cause lymphocyte apoptosis

3.) bacteria stimulate release of cytokines which cause lymphocytes to leave bloodstream to the tissues to fight infection

Lymphopenia: Depletion/Loss

Lymphocytes are lost from the vascular system with loss of lymph or lymph-rich fluid

Lymphopenia: Decreased Production

bone marrow is not producing lymphocytes

examples of things that can cause decreased production of lymphocytes

-radiation

-chemotherapy

-immunosuppressive drugs

-congenital immunodeficiencies

Monocytosis

increase in monocytes

Two causes of monocytosis

1.) inflammation/infection

2.) corticosteroids

Monocytosis and inflammation/infection

can be due to both acute and chronic inflammation

Why does inflammation/infection cause monocytosis?

it leads to increased production of monocytes in the bone marrow

Granulomatous inflammation

Chronic inflammation characterized by granuloma formation

Monocytosis and corticosteroids

corticosteroids cause mobilization of monocytes from marginal pool back into circulating pool

Four total features of corticosteroid response:

1.) lymphopenia

2.) eosinopenia

3.) monocytosis

4.) neutrophilia

Monocytopenia

usually not clinically significant; rarely may be due to bone marrow injury

Dogs:

-predominating WBC

-size of lymphocytes

-neutrophils predominate

-small lymphocytes

Increased neutrophils in dogs are a good indication of...

inflammation

Corticosteroid response can include what value in dogs?

monocytosis

Cats:

-predominating WBC

-size of lymphocytes

-neutrophils predominate

-small lymphocytes

Increased neutrophils in cats are a good indication of...

inflammation

Corticosteroid response can include what value in cats?

mild lymphocytosis

Cattle:

-predominating WBC

-size of lymphocytes

-lymphocytes predominate

-large lymphocytes

Will chronic or acute inflammation cause left shift in cattle? Why?

acute; they have a small storage pool of lymphocytes in their bone marrow, so it doesn't take much for the left shift to occur

Horses are more prone to what type of leukocytosis?

physiologic

Equine neutrophils are typically more _________ than other species

segmented

Describe the values on this CBC

-leukocytosis

-neutrophilia

-normal bands

-lymphopenia

-monocytosis

This CBC is compatible with what cause?

stress leukogram

(LEMN)

-lymphopenia

-eosinopenia *normal in this case but don't need all four to be considered stress leukogram

-monocytosis

-neutrophilia

Describe the values on this CBC for 10/25

-leukocytosis

-neutrophilia

-appropriate left shift (band neutrophils are less than segmented)

-lymphopenia

-monocytosis

-normal eosinophils

Based on the blood values for 10/25, what is likely going on?

inflammation and stress mixed pattern

evidence of inflammation --> left shift

evidence of stress --> lymphopenia, neutrophilia and monocytosis

Describe the values on this CBC for 11/1

-leukocytosis

-neutrophilia

-inappropriate left shift (band neutrophils are higher than segmented)

-lymphopenia

-monocytosis

-normal eosinophils

-metamyelocytes

-myelocytes

Based on the blood values for 11/1, what is likely going on?

extreme inflammation (due to metamyelocytes, myelocytes, and inappropriate left shift)

Describe the values on this CBC for 11/4

-leukocytosis

-neutrophilia

-appropriate left shift (band neutrophils are lower than segmented)

-lymphopenia

-normal monocytes

-normal eosinophils

-metamyelocytes

Based on the blood values for 11/4, what is likely going on?

leukemoid response

-marked leukocytosis

-segmented neutrophils above 50 x 10^L

-appropriate left shift

-lymphopenia