What is your diagnosis? Peritoneal fluid from an Arabian horse after colic surgery.

The research study is about an Arabian horse that underwent surgery for intestinal obstruction which later developed complications. Post-operatively, a substance used during surgery, sodium carboxymethylcellulose (CMC), was found to be phagocytosed by macrophages, a behavior which hadn’t been reported before.

Background and Purpose of the Study

• The objective of the study was to investigate the case of a 16-year-old Arabian horse, which was brought for treatment after exhibiting colic symptoms for 4 hours.
• The initial diagnosis indicated a blockage in the small intestine. A surgical procedure was then performed revealing that the cause of the blockage was a strangulating lipoma.
• The surgery involved removing 25 feet of the horse’s small intestine, but the horse developed further complications later — an obstructive ileus due to the formation of adhesions. This necessitated a second surgical procedure (laparotomy).

Post-Surgery Observations and Findings

• Throughout the surgeries and recovery, the horse’s abdominal region was cleansed (lavaged) with a substance known as sodium carboxymethylcellulose (CMC).
• One week after the second surgical procedure, the horse’s peritoneal fluid, found in the abdominal cavity, was analyzed. The analysis showed an inflammatory exudate and an unusually high number of macrophages (a type of white blood cell) which had consumed (phagocytosed) unknown substances.
• The consumed material was described as amorphous to granular and pink to magenta. Also, similar extracellular mounds of material were observed.

Conclusion of the Study

• The unknown matter phagocytosed by the macrophages was identified as sodium carboxymethylcellulose (CMC), the same substance used to wash the abdominal area during and after the surgeries.
• This recognition marked the first documented instance where macrophages were seen to have consumed CMC in peritoneal fluid.
• The association between CMC and its phagocytosis by macrophages in this context forms the primary take-away of this study, though how this finding might contribute to veterinary medical knowledge or practice is not made explicit within this abstract.