Neutrophilia

• Neutrophilia is an increase in the number of neutrophils in the blood.
• Neutrophilia is often accompanied by the release of substantial numbers of immature neutrophils into the blood stream.
  • Do not have segmented nuclei.
    • Nuclei appear as elongated bent tubes in the cytoplasm .
  • Are called "band cells".
  • The presence of band cells in the blood represent an intense need for neutrophils due to them being lost in the purulence.
  • When the percentage of these immature forms is high, it is referred to as a "left shift".

Causes of Neutrophilia

Purulent Foci:

• Purulent foci and abscesses in the body produce substantial neutrophilia.
• For example, neutrophilia is produced in
  • Pyometra
    • Pus in the uterus.
  • Empyema
    • Pus in a body cavity
      • E.g. Nocardia infection in the thoracic cavity.
• In very severe infections, such at those above, the neutrophil granules become more apparent in the cytoplasm and stain bluish, and some cytoplasmic vacuolation may be seen.
  • These 'toxic' neutrophils have decreased bactericidal capability and do not respond as quickly to chemotactic stimuli.

Bacteria

• Bacteria,particularly pyogenic forms, cause neutrophilia.

Necrosis

• Necrosis of any kind will result in neutrophilia.
  • Necrosis from burns, malignancies and infection are particularly involved.

Fungi

• For example, aspergillosis.

Viruses

• Neutrophils may be present, but are not the main component of inflammaory cells.
• Examples:
  • Canine Distemper
  • Equine Herpes Rhinotracheitis
  • Infectious Bovine Rhinotracheitis

Parasites

• Neutrophils may be present, but are not the main componentof inflammatory cells.
• Examples
  • Fasciola hepatica
  • Toxoplasma gondii

Immune-Mediated Conditions

• Neutrophils may be present, but are not the main component of inflammatory cells.
• Examples:
  • Rheumatoid arthritis
  • Systemic Lupus Erythematosus
  • Autoimmune Haemolytic Anaemia

Other Factors

• Other factors which will produce a neutrophilia are:
  • Excitement, fear, and strenuous exercise in young animals.
  • Corticosteroids; either :
    • Released endogenously in pain or thermal stress, or
    • Exogenous therapeutic administration.
      • Neutrophilia oocures 4-8 hours post administration of the corticosteroid drug.