Surgical treatment for acute small intestinal obstruction caused by Parascaris equorum infection in 15 horses (2002-2011).

Reasons for performing study: There is a consensus in the veterinary literature that Parascaris equorum (ascarid) impaction carries a poor prognosis. Hence surgery is often delayed and foals are often subjected to euthanasia after diagnosis of ascarid impaction is established. Our clinical impression was that ascarid impaction carries a better prognosis than previously reported.

Objectives: Our expectation was that manually evacuating the impaction into the caecum, thus refraining from opening the small intestine, would improve the prognosis for survival of horses with ascarid impaction. The aim of this study was to examine medical records of horses treated surgically for ascarid impaction, record their clinical findings and evaluate the association of outcome with the method of relieving the impaction.

Methods: The medical records of all horses presented to our hospital between October 2002 and December 2011 that underwent exploratory celiotomy for ascarid impaction were reviewed. Information retrieved from the medical record included surgical findings, surgical technique, complications, short- and long-term survival. The association between categorical variables was assessed using the Fisher's exact test. A P value < 0.05 was considered statistically significant.

Results: Fifteen horses fulfilled the inclusion criteria. Eighty percent of horses (12/15) survived to discharge and 60% (6/10) survived for at least one year. Five horses are doing well but are still in convalescence. Horses that underwent small intestinal enterotomy or resection and anastomosis (n = 5) were less likely to survive to discharge (P = 0.022).

Conclusions: In our study, manual evacuation of ascarid impaction into the caecum, while refraining from opening the small intestine resulted in significantly improved survival in horses with ascarid impaction.

Potential relevance: Refraining from opening the small intestine may be the key to improving surgical outcome in horses with ascarid impaction.