Veterinary Clinical Medicine-I (General and Systemic)

CLINICAL PATHOLOGY

Complete blood count

• Cattle with persistent purulent inflammation have leukocyte counts ranging from 4,000-15,000/µL, with neutrophilia.
• A degenerative left shift (band neutrophils outnumbering segmented neutrophils). Cattle with acute diffuse peritonitis will also have a degenerative left shift. In chronic cases, a mature neutrophilia is common.
• Neutrophil counts in these individuals are often greater than 4,000/µL. Affected cattle also will show hyperfibrinogenemia, with fibrinogen concentrations greater than 1,000 mg/dL.
• Fibrinogen is an acute phase protein, and in cattle it may be the best indicator of acute inflammation because fibrinogen concentrations often increase prior to development of neutrophilia.
• Hematology data can be used to detect inflammation, but generally cannot identify a specific cause of inflammatory disease. Other tests may be useful in differentiating between different inflammatory diseases, such as TRP

Serum biochemical profile

• The most common chemistry abnormality associated with TRP is hyperproteinemia with a hyperglobulinemia. Some authors suggest that a total serum protein concentration greater than 10 mg/dL is highly suggestive of TRP.
• In one study of cattle suspected of having TRP that also had a total plasma protein concentration of 100 g/L (10mg/dL) had an 83% chance of having TRP, 83% of the cattle with a total plasma protein concentration of 10 mg/dL had TRP.
• Other chemistry abnormalities associated with TRP may include hypochloremia, hypokalemia, and metabolic alkalosis; these abnormalities occur secondary to ruminal hypomotility and/or vagal indigestion. Hypochloremic metabolic alkalosis may occur due to sequestration of hydrochloric acid in the rumen caused by rumen stasis or vagal indigestion.
• Hypokalemia is caused primarily by anorexia, but may be potentiated slightly by ion exchange caused by the alkalosis and/or abomasal reflux into the rumen. With alkalosis, intracellular H⁺ ions can be exchanged for extracellular K⁺ ions, decreasing serum potassium concentrations. This effect is minor compared to the K⁺ ion shifts associated with acidosis.

Abdominocentesis

• Normal peritoneal fluid of an adult cow is straw-colored, clear, and odorless. Protein and fibrinogen concentrations can vary from 1.0-3.0 g/dL and 100-500 g/dL, respectively. The nucleated cell count should be less than 10,000 cells/µL.
• The majority of nucleated cells are non-degenerate neutrophils and mononuclear cells.
• Turbid samples or samples containing gross pus or fibrin are indicative of peritonitis.
• It is, however, normal for bovine peritoneal fluid to clot upon standing. Nucleated cell count, cell percentages, and character of cells present are suggestive of disease.
• If a sample contains immature, degenerative, or toxic neutrophils purulent peritonitis is present.
• Purulent peritonitis is indicated by an abdominal fluid sample with greater than 40% neutrophils. The presence of intracellular bacteria and/or degenerate neutrophils indicates septic peritonitis.