(E48) Changes in Peritoneal Fluid Associated with Colitis in Adult Horses

Abstract: Background- Colitis can cause severe colic in horses and may not cause diarrhea, making it difficult to distinguish from surgical lesions. Additionally, bacterial translocation secondary to reduced mucosal integrity can lead to secondary peritonitis. Objectives- To identify changes in peritoneal fluid secondary to colitis, and to identify the percentage of positive cultures from peritoneal fluid. Animals- 27 adult horses (>2 years of age) with colitisMethods- Prospective clinical study enrolling horses hospitalized with colitis. Initial laboratory data were recorded including peripheral WBC and neutrophil count, lactate, albumin, glucose and creatinine. Peritoneal lactate and protein were measured and fluid was submitted for culture, cell count, and cytology. Variables were compared between survivors and non-survivors using a Mann-Whitney test (p ≤ 0.05). Previously established reference ranges (Brownlow et al, 1981) for peritoneal cell count and protein were compared with colitis cases using unpaired t-tests. Results/Findings- 20/27 (74.1%) horses survived to discharge. Median peritoneal cell count was 2.0*103 cells/L (range 0.3-205.3*103 cells/L). Median peritoneal lactate was 1.9 mmol/L (range 0.4-14.7 mmol/L). Median peritoneal protein was 2.6 g/dL (range 0-5.6 g/dL) and median peripheral lactate was 1.4 mmol/L (range 0.6-13.3 mmol/L). 6/22 (27.3%) peritoneal fluid cultures yielded positive bacterial growth. Peritoneal protein was increased compared to the normal reference range. There were no significant differences between survivors and non-survivors. Conclusions and Clinical Importance- Increased protein can be present in peritoneal fluid from colitis cases which is not related to survival. Positive bacterial cultures were obtained in several horses but did not influence the outcome.