Leukocyte Patterns and Fibrinogen

What are the 3 classic patterns of Leukocyte responses?

1. Physiologic Leukocytosis

2. Stress Leukocytosis

3. Inflammatory Leukocytosis

What causes a physiologic leukocytosis?

Excitement (epinephrine release)

What are the characteristic findings of an excitement leukon?

1. Mild neutrophilia w.o a left shift

2. Mild/Moderate lymphocytosis

   1. Although can be normal lymphocyte count

3. Normal monocyte, eosinophils and basophils, but can be mildly increased

T/F: Physiologic leukogram can be a common occurrence in young healthy cats

True, they can be excited/scared from visiting the clinic and or getting blood drawn

What is the mechanism by which a Physiologic Leukocytosis occurs?

• Patient is excited or scared

• Increased B.P and HR → Rapid mobilization of marginated neutrophils

What are the characteristic findings of a stress leukon (4)?

• Neutrophilia

  • Usually mild, sometimes moderate

    • NEVER MARKED

  • No left shift

• Lymphopenia

  • Most reliable finding

  • Mild, moderate, marked

• Eosinopenia

  • If detectable

• Monocytosis

  • Usually mild

    • NEVR MARKED

What are the mechanisms that cause a Stress Leukon?

• Neutrophilia is caused by increased release from B.M

  • Also from decreased “stickiness“ and emigration of neutrophils from the vasculature

• Lymphopenia is due to short term redistribution

  • occurs when lymphocytes shift from the circulating blood pool to the marginal pool (endothelium), lymphoid tissues (lymph nodes, spleen), or specific infection sites, resulting in a lower lymphocyte count in peripheral blood tests despite normal total lymphocyte counts in the body

• Eosinopenia

  • Short-term due to decrease marrow release

  • Long-term due to prolonged use of corticosteroids → Dec. eosinophil production

• Monocytosis due to decreased emigration

Longterm use of what drug can cause lymphopenia via lympholysis

Corticosteroids

After a single treatment of corticosteroids, the leukogram will return to normal after how long?

24 hours

After prolonged treatment of corticosteroids, the leukogram will return to normal after how long?

2-3 days

If a __________ is present then a stress leukogram should be on your differential list

Lymphopenia

What can cause a Lymphopenia to be present without a neutrophilia in a stress leukogram?

• Prolonged corticosteroid use

• Hyperadrenocorticism

What are the characteristic findings of an Inflammatory Leukon?

• Neutrophilia with a regenerative left shift

• ± monocytosis

When an inflammatory disease is present what is a more favorable sign, neutrophilia or neutropenia? Why?

• Neutrophila

  • The B.M is releasing neutrophils at a rate higher than they are entering the tissues

If a ____ ____ is present then there is always inflammation

Left Shift

A __________ can persist or intensify following abrupt removal of the inflammatory site

• Neutrophilia

  • Ex: A day a a pyo the neutrophils can still be high/elevated

Because inflammatory disease can cause Leukocytosis, it can commonly be confused with ________, what can aid in differentiating between these conditions?

• Leukemia

  • Clinical Signs and toxic changes

Provide a morph for the leukogram

• Marked leukocytosis

  • Marked neutrophilia

    • Mild regenerative left shift

    • Marked monocytosis

Categorizing the chronicity of inflammatory disease/inflammatory leukograms can be difficult, what tools/indicators can you use to do so?

• Clinical Signs (how long has the patient experienced inflammation)

• # of segs

  • How long has the bone marrow had to expand production?

    • If it has had enough time then it could be a regenerative left shift

• Degree of monocytosis

  • Marked = chronic inflammation

• Presence of degenerative left shift = acute

T/F: Chronic inflammation with no left shift can occur

True, in this case the bone marrow has had the chance to respond, the body essentially adapts to a new normal and ramps up production

Provide a morph for this leukogram. What pattern is this?

• Marked leukocytosis

  • Marked neutrophilia

  • Mild lymphopenia

  • Marked monocytosis

• Chronic Inflammation

  • No bands are present because the bone marrow has caught up in the production of neutrophils

  • The marked segs, marked leukocytosis, and marked monocytosis

T/F: Leukogram pattern can present as combination

True

An animal with lumphopenia, a neutrophilia and a left shift has what leukogram pattern(s)

• Inflammatory leukogram

• Stress (corticosteroid) leukogram

What is fibrinogen?

• An inflammatory protein made by the liver when the body is experiencing inflammation

  • the liver will produce more fibrinogen when an inflammatory process is going on anywhere in the body

• It acts in the coagulation cascade as a coagulation factor

Elevated fibrinogen would be indicative of __________ or __________

• Inflammation

• Dehydration (less water in bloodstream → increase of protein concentration)

What is a Protein/Fibrinogen ratio? What is its importance?

A veterinary diagnostic tool used to differentiate dehydration from inflammation in animals, particularly horses and cattle (large animal)

What do the following P/F ratios tell us?

1. If the P/F ration is <10

2. The P/F ration is >15

3. P/F ratios between 10-15

1. Inflammation (Fibrinogen has gone up relatively more than P)

2. Dehydration (or just normal)

3. Grey Zone (no interpretation)