Protein Losing Enteropathies in Horses – More Than Just Ulcers

Collection of blood samples for a complete blood count (CBC) and serum biochemistry profile is generally warranted in horses with ill thrift or recurrent colic. The CBC is probably the less rewarding of these tests. Frequently, mild anemia (packed cell volume [PCV] of 27-30%) is the only abnormality detected. Mild anemia may be a consequence of chronic disease but it is also important to recognize that PCV values of 30- 32% may be normal for adult horses that are not in a regular exercise program. Occasionally, however, rare conditions such as leukemia may only be detected with a CBC.
Serum biochemistry results can be quite rewarding in some patients; for example, detection of azotemia with hypercalcemia is nearly pathognomonic for chronic renal disease and liver disease can be supported by an increase in γ-glutamyl transferase (GGT) activity. It is also important to interpret total protein, albumin, and globulin concentrations. Detection of either increased total protein concentration or hypoproteinemia typically directs further diagnostic testing. Specifically, an elevated protein concentration is a consequence of an increase in globulin concentration as the only cause of hyperalbuminemia is dehydration. An increase in globulin concentration supports chronic inflammatory disease including infection (e.g., abdominal or thoracic abscess, cholangiohepatitis, pleuropneumonia, and others) or neoplasia. In contrast, a decrease in total protein concentration in the horse is almost always indicative of a protein-losing enteropathy (PLE), although a rare horse with hypoproteinemia may have neoplasia with large volumes of pleural or peritoneal effusion or a glomerulopathy […]