Granulomatous enteritis in a young standardbred mare.

This research study details a case of granulomatous enteritis, a rare inflammatory bowel disease, diagnosed in a four-year-old standardbred mare. The mare had been experiencing chronic weight loss, depression, fluid accumulation under the skin (dependent edema), but no diarrhea. The findings reveal both severe and minor abnormalities in almost the entire small intestine and parts of the stomach and the colon, respectively.

Diagnosis and Symptoms

• The researchers diagnosed the mare with granulomatous enteritis, an uncommon inflammatory bowel disease marked by inflamed granulomas (clusters of abnormal immune cells).
• The mare presented various symptoms, including chronic weight loss, depressive behavior, and dependent edema (an abnormal swelling due to accumulation of fluid in tissues), but did not exhibit diarrhea, a common symptom in most intestinal disorders.

Other Clinical Findings

• The animal exhibited hypoproteinemia (lower-than-normal protein levels in the blood), specifically hypoalbuminemia, which is the deficit of albumin in the blood. Albumin is a vital protein made by the liver, and a deficiency often suggests liver or kidney disease.
• Lymphocytopenia, a condition characterized by lower-than-average level of lymphocytes (a type of white blood cell) in the blood was also evident; this typically implies a weakened immune system.
• The study uncovered negligible carbohydrate absorption from the small intestine, which demonstrated its impaired function.

Pathological Changes

• The pathological changes involved almost the entire small intestine. These included proprial infiltration leading to partial villous atrophy, which involves the inflammation or invasion of the propria (the connective tissue of the intestinal mucosa) and subsequent partial wasting away or decrease in size of the villi (small finger-like projections that increase the internal surface area of the intestinal walls).
• The team found granuloma formations beneath the intestinal muscle layer (muscularis), which were most severe in the ileum (the final part of the small intestine).
• Slight poorly differentiated cell (lymphocytes and histiocytes) infiltration was identified in the stomach and the colon, revealing that the disease had marginally affected these areas as well.
• Crucially, no acid-fast organisms were found, indicating that the disease wasn’t caused by certain types of bacteria, such as Mycobacterium (the group that contains tuberculosis and leprosy).