Volvulus nodosus of the small intestine: differences in foals and adults

Background: Volvulus nodosus is a strangulating lesion of the small intestine described only in foals and in just one case in older horses. Huskamp et al (1982, 1998) described the pathophysiology of volvulus nodosus in foals, but to date there is no description of the pathophysiology of volvulus nodosus in adults. Objectives: to describe the different features of volvulus nodosus in adult horses and in foals. Study design: Clinical case series. Methods: Analysis of the clinical and anatomical features of 2 foals and 3 adults presenting with volvulus nodosus. Results: Clinical presentation between foals and adults differed mainly for the mild or absent pain showed by older horses. Clinical and ultrasonography findings were similar. At surgery or necropsy we found anatomical differences between adults and foals. In adults the volvulus didn’t involve the mesentery that instead forms a hernia sac in foals. Further, in adults, there wasn’t involvement of the ileum, but two loops of jejunum resulted one wrapped around another in all 3 cases. After accurate analysis of one case at necropsy, we found that in adults one loop act as a “post” around which another loop turns around. The weight of this loop causes then the formation of a half-hitch formed by the two loops and their mesentery. This cause strangulation and necrosis of two separate tract of jejunum. Main limitations: Small number of cases included. Conclusions: Volvulus nodosus may occur in adult horses with significant differences compared to foals. Knowing the presentation and pathophysiology of volvulus nodosus may help equine surgeons to resolve selected cases of small intestinal strangulation in adult horses.