Large Colon
Left Dorsal Displacement
Basic Information 
Clinical Presentation
History, Chief Complaint
• Clinical signs of LDDLC are variable depending on the tension on the nephrosplenic ligament, pull on the mesentery, distension of the large colon, and secondary gastric distension. Most affected horses show signs of moderate pain, but severe pain may occur. Some horses may have chronic displacement with little gas distension and little to no signs of discomfort.
• Horses frequently have decreased to absent fecal production and may have abdominal distension. In some horses, the visible distension is confined to the area of the left paralumbar fossa.
Physical Exam Findings
• Because LDDLC is generally a nonstrangulating obstruction, affected horses are cardiovascularly stable.
• Physical examination findings may include tachycardia, abdominal distension, decreased or absent borborygmi, and signs of dehydration.
• As distension becomes more severe, compromise to the cardiovascular system and respiratory system are possible. With chronicity or severe distension, ischemia of the entrapped region of the left colons may occur, and clinical signs and physical examination will reflect the associated cardiovascular compromise.
Etiology and Pathophysiology
• It is likely that changes in motility or gas distension of the large colon result in abnormal migration of the pelvic flexure.
• The left large colon may migrate lateral to the spleen and dorsally until it reaches the nephrosplenic space or the pelvic flexure may migrate cranially and then back caudally to pass through the nephrosplenic space from cranial to caudal.
• Frequently, the left colon rotates 180 degrees such that the left dorsal colon is ventral to the left ventral colon.
Diagnosis 
Differential Diagnosis
• Other causes of moderate abdominal pain: Simple or nonstrangulating obstructions of the gastrointestinal tract such as feed or sand impaction, enterolithiasis, large colon tympany, other large colon displacements, large intestinal intraluminal obstructions, small colon impactions, and ileal impactions
• Other causes of large intestinal distension on examination per rectum: Feed or sand impaction, enterolithiasis, large colon tympany, other large colon displacements, large colon volvulus, and other intraluminal obstructions
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