Enteroliths in Horses—a retrospective study of 30 cases

Abstract

SUMMARY In a retrospective study of selected cases, abdominal colic in 30 horses was attributed to enterolith obstructions of the large intestine. Obstructions caused by “true” enteroliths were confined to horses more than four years old. Prominent clinical features were recurrent mild abdominal pain, inappetance, gaseous distension and minimal intestinal motility. The various aspects of the clinical syndrome, including diagnostic problems and clinical management, are discussed. Most obstructing enteroliths were found near the beginning of the small colon and most horses contained only a single major concretion. Enteroliths were formed by mineral deposition in concentric layers about a central nidus of ingested material and were spherical or tetrahedral in shape. Intestinal concretions were found to consist primarily of ammonium magnesium phosphate. RÉSUMÉ Dans une étude rétrospective de cas sélectionnés, les coliques abdominales de trente chevaux ont été attribuées à l'existence d'obstructions par entérolithes. Les obstructions causées par des entérolithes proprement dits, ont été trouvées chez des chevaux âgés de plus de quatre ans. Les signes cliniques principaux ont été une douleur abdominale d'intensité moyenne et récidivante, de l'inappétence, une distension gazeuse et une motilité intestinale diminuée. Les aspects variés du syndrome clinique sont discutés, y compris les problèmes diagnostiques et cliniques. Les entérolithes les plus gênants ont été trouvés à l'entrée du petit colon et la plupart des chevaux n'avaient qu'une seule concrétion. Ces entérolithes étaient constitués par des dépôts minéraux, en couches concentriques autour d'un noyau central d'ingesta. Leur forme était tantôt sphérique, tantôt tétraédrique. Ces concrétions étaient composées essentiellement de phosphates ammoniaco‐magnésiens. ZUSAMMENFASSUNG In einer retrospektiven Untersuchung ausgewählter Fälle wurde das Auftreten einer abdominalen Kolik bei 30 Pferden enterolithischen Obstruktionen des Dickdarmes zugeschrieben. Obstruktionen verursacht durch “echte” Enterolithen konnten nur bei mehr als 4‐jährigen Pferden beobachtet werden. Hervorstehende klinische Eigenschaften bestanden in milden Abdominalschmerzen, Inappetenz, Blähung und minimaler Darmmotilität. Die verschiedenen Aspekte des klinischen Syndroms, einschliesslich diagnostischer Probleme und Pflege werden diskutiert. Die meisten der Verschlüsse durch Enterolithen wurden nahe beim Uebergang ins kleine Kolon gefunden und bei den meisten Pferden konnte nur ein grösserer Stein festgestellt werden. Die Enterolithen wurden gebildet durch Mineralablagerung in konzentrischen Schichten um einen zentralen Kern von Ingesta. Sie wiesen eine sphärische oder tetrahedrische Form auf. Vor allem bestanden diese Konkremente aus Ammonium‐Magnesium‐Phosphat.

Peritoneal fluid changes in horses subjected to small colon distension

“…Comparable results were obtained with a similar distension model in the rectum, where none of the horses with rectal pressures up to pressures of up to 220mm of Hg demonstrated signs of severe pain (Skarda & Muir 2003). Such results corroborate with previous observations that the deterioration in the clinical status of the equine patient occurs slowly in cases of simple obstruction of the small colon (Datt & Usenik 1975, Blue 1979, Gay et al 1979, Dart et al 1992, Hassel et al 1999, Rhoads et al 1999.…”

“…Horses affected by simple obstruction of the small colon are reported to do not show clinical signs of acute abdominal disease as overtly as horses with diseases in other segments of the gastrointestinal tract (Datt & Usenik 1975, Blue 1979, Gay et al 1979, Dart et al 1992, Hassel et al 1999, Rhoads et al 1999. In addition, blood and peritoneal fluid variables routinely analysed are generally within the normal range values in most of the reported cases of obstructions by ingesta impaction (Rhoads et al 1999), enteroliths (Hassel et al 1999), and foreign bodies (Gay et al 1979).…”

Three cases of obstruction of the small colon by a foreign body

“…In case of dehydration or acidosis, fluids are given i.v. (2,7,13). In such cases a choice is made at our clinic between mineral oil or sodium sulphate.…”

“…After being formed in the large colon, the enterohths usually produce an obstruction in the funnel-shaped part of the transverse colon or farther down the small colon (colon descendens). Because medical therapy is likely to fail in these cases, an operation is suggested (2,7). This is performed on the standing animal through the flank or, with the animal under general anaesthesia, through the linea alba (2,7,8).…”

“…Because medical therapy is likely to fail in these cases, an operation is suggested (2,7). This is performed on the standing animal through the flank or, with the animal under general anaesthesia, through the linea alba (2,7,8). The latter method is recommended because the enteroliths are usually found in the small colon, which because of its anatomical relations is difficult to bring into the operation wound (therefore, after an exploratory laparotomy from the flank, the horse has to be laid down under general anaesthesia and a new incision made in the linea alba (2, 8)).…”