CHAPTER 90 Cecal Impaction
Cecal impactions may consist of solid ingesta, or they may be fluid filled. On the basis of these clinical findings, it may be more relevant to divide cecal impaction into two syndromes: (1) primary impactions that result from excessive accumulation of solid ingesta in the cecum and (2) secondary impactions that are typically fluid filled, appear to be the result of cecal dysfunction, and are frequently associated with postoperative pain.
In horses with primary cecal impactions, there is typically a 5- to 7-day onset of signs of abdominal pain similar to those seen during development of large colon impaction. During this gradual onset, veterinarians may use treatments for impactions, such as intravenous administration of analgesics and nasogastric administration of laxatives like mineral oil, dioctyl sodium sulfosuccinate, or magnesium sulfate (Epsom salts). However, it is crucial to differentiate between cecal and large colon impactions because cecal impactions have a propensity to rupture before development of severe abdominal pain or systemic evidence of shock. Horses with cecal impaction are best referred as early as possible.
The two types of impactions are differentiated by rectal palpation. Because the cecum is attached to the dorsal body wall by its mesentery, the impacted cecum is always on the right side of the abdomen. In contrast, much of the large colon is not attached to the body wall, and impacted portions can shift from the left to the right side of the abdomen. Because an impaction palpated on the right side of the abdomen can be difficult to interpret, the dorsal surface of a right-sided impaction should be carefully palpated to determine whether it is attached to the dorsal body wall. This is possible in approximately 90% of affected horses. If the impacted viscus is attached to the dorsal body wall, it is best to assume it is a cecal impaction and offer the client a referral. At the referral center, additional medical therapy may be used, including intravenous fluids. However, in my opinion, it is best to manage these horses surgically because it is difficult to determine the full extent of impaction or integrity of the cecal wall on the basis of rectal palpation alone.