Ultrasonography of the abdomen in the horse with colic

Abstract

Ultrasonography has proven to be very useful for evaluation of the urinary and gastrointestinal tracts in foals and adult horses. Gastric distension, small intestinal ileus, inflammation of the large intestine, right dorsal colitis, intraabdominal masses and neoplasia, intraabdominal abscesses, intussusceptions, ileal muscular hypertrophy, intraluminal ascarids, inguinal herniation, impactions, entrapment of the large colon in the nephrosplenic space, liver lobe torsions, colelithiasis, diaphragmatic hernias, displacement of the colon, peritonitis, intraabdominal hemorrhage, and bowel rupture can be detected by abdominal ultrasound. Ultrasound can be used to guide liver biopsies and abdominocentesis. For the latter, accumulations of peritoneal fluid can be localized and inadvertent puncture of the spleen and intestine can be avoided. Assessment of peristalsis by ultrasonography is subjective but valuable, and horses with small intestinal obstruction in this study had either pendular peristalsis or complete atony. In 67 horses with small intestinal obstruction in this study, all cases were diagnosed beforehand by ultrasonography, whereas 10% were missed by rectal palpation. Four horses were incorrectly diagnosed with nephrosplenic ligament entrapment of the large colon by ultrasonography (false positive), but ultrasonographic absence of this lesion in other horses was confirmed at surgery. Percutaneous ultrasound is non invasive, is not restricted to foals, ponies, or others that are too small for rectal palpation, requires little time, and can be useful in the decision for surgical or medical treatment.