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

Summary 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 foals. Study design Clinical case series. Methods Analysis of the clinical and anatomical features of two foals and three adults presenting with volvulus nodosus. Results Clinical presentation between foals and adults differed mainly in the mild or absent pain shown 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 did not involve the mesentery that instead forms a hernia sac in foals. Further, in adults, there was no involvement of the ileum, but two loops of jejunum resulted in one wrapped around another in all three cases. After accurate analysis of one case at necropsy, we found that in adults, one loop acts as a ‘post’ around which another loop turns. The weight of this loop then causes the formation of a half‐hitch formed by the two loops and their mesentery. This causes strangulation and necrosis of two separate tracts 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 resolve selected cases of small intestinal strangulation in adult horses.