Obstruction of equine small intestine associated with focal idiopathic eosinophilic enteritis: an emerging disease?

Idiopathic focal eosinophilic enteritis (IFEE) is a rare disease in the horse and few cases have been reported in the literature. The objective of this paper was to describe the clinical, surgical, histological features and post-operative progress of 12 horses with IFEE, a disease that had not been identified in the authors' hospital population prior to 2000. Diagnosis of IFEE was made at laparotomy and confirmed by histological examination of resected abnormal small intestine. In all 12 horses colic was associated with jejunal obstruction involving visibly striking and palpably thickened serosal plaques or circumferential constrictions. Surgical resection of affected intestine was performed in 10 horses, of which seven completely recovered. In one horse, on which surgical resection was not performed, ingesta re-obstructed post-operatively at one of the lesions. Histological examination of resected intestines revealed, in all cases, severe transmural enteritis in which eosinophilic leucocytes were the predominant inflammatory cells. No helminths were identified and the cause of this lesion is not known. IFEE is an uncommon but significant cause of small intestinal obstruction for which surgical resection can be curative. The gross lesions may be under-recognised and histology is essential for diagnosis.