Cecal, Caecum Impaction in Horses
An impacted cecum can be palpated on rectal examination in the right flank area. Generally a slow, gradual onset of clinical signs with mild vacillating-type colic. Cecal rupture can be a complication of impaction, leading to peritonitis and death.
The most common sites of impaction are the pelvic flexure region of the left colon, the junction of the right dorsal colon with the transverse colon, and the base and body of the cecum. The pelvic flexure and transverse colon regions are anatomically predisposed to obstruction because of the dramatic changes in size.
Horses with simple impactions of the cecum or large colon exhibit mild intermittent signs of colic, and there is minimal evidence of systemic deterioration unless the impaction has a prolonged course. Generally, the heart rate is only slightly increased. Intestinal sounds are usually heard on auscultation of the abdomen and may be associated with the onset of pain as the affected portion of the intestine contracts against the obstruction.
Cecal impactions tend to be a primary cause of colic in horses >8 yr old. Alternatively, impactions may be seen in horses hospitalized for other reasons and are often associated with abrupt rupture of the cecum in these cases.
The underlying reason for impaction of the cecum is unknown, although it has been speculated that cecal muscular activity is abnormal in affected horses. Other predisposing factors include feed that is too coarse, diseased or poorly managed teeth, and insufficient water intake. In one clinical study, Morgan, Arabian, and Appaloosa breeds were over
- represented among horses with cecal impaction, and it has been proposed that the condition may develop secondary to infection with the tapeworm Anoplocephala perfoliata . Impactions also may develop secondary to other intestinal diseases and may be associated with prolonged hospitalization. Consequently, the fecal output of horses being treated for other abnormalities should be assessed on a routine basis. This is especially important in horses receiving NSAID on a daily basis.
Diagnosis is made on rectal examination. Although the most common site of obstruction is considered to be the pelvic flexure region of the large colon, the impacted ingesta actually fills much or all of the left ventral colon. The impacted mass may be felt extending cranially in the abdomen, and the affected segment of bowel identified by palpating the longitudinal bands on the surface of the ventral colon. Impaction of the cecum is relatively easy to identify because the mass is situated in the right paralumbar region. The cecum can be definitively identified by palpating the taut ventral cecal band and the fat and blood vessels overlying the medial cecal band. Peritoneal fluid analysis may be normal, or the total protein concentration may be increased as the course becomes more prolonged.
References: [Web Reference] PubMed
Southwood LL. Acute Abdomen. Clinical Techniques in Equine Practice 2006;5:112-126 [Web Reference]
Sasaki N et al. Effects of mosapride, a 5-hydroxytryptamine 4 receptor agonist, on electrical activity of the small intestine and cecum in horses. AJVR 2005;66:1321-1323
- Tachycardia, rapid pulse, high heart rate
- Anorexia, loss or decreased appetite, not nursing, off feed
- Congestion oral mucous membranes, erythema, redness oral mucosa
- Decreased amount of stools, absent feces, constipation
- Decreased borborygmi, gut sounds, ileus
- Increased borborygmi, gut sounds
- Palpable dilated bowel internal paplation
- Fever, pyrexia, hyperthermia
- Internal abdominal mass, swellings, adhesions abdomen
- Sweating excessively, hyperhidrosis
- Dullness, depression, lethargy, depressed, lethargic, listless
- Colic, abdominal pain
Consequently, there is some controversy regarding the best method of treatment. Because medical therapy in some clinical studies has been unsuccessful in 50% of the cases, surgical removal of the impacting mass followed by an ileocolostomy has been strongly recommended. Other veterinarians report good results with aggressive medical therapy, particularly if abdominal pain associated with the cecal impaction was the primary reason the horse required veterinary attention.
Medical treatment of horses with cecal or large-colon impaction involves the administration of analgesics as necessary, large volumes of balanced IV fluids, and intragastric administration of either mineral oil or dioctyl sodium sulfosuccinate and water. Feed should be restricted until the impaction is relieved. Many veterinarians consider aggressive fluid therapy to be the mainstay of treatment. Balanced electrolyte solutions are administered to induce movement of fluid from the plasma into the lumen of the intestine.
This form of treatment may require administration of >50 L of fluid/day to a 450-kg horse until the impaction is resolved. Recently, interest has increased in using enteral fluid therapy to treat horses with impactions, primarily because enteral fluid therapy is significantly less expensive than IV fluid therapy. The clinical results with enteral fluid therapy have been rewarding, and the results of experimental work in healthy horses have shown that enteral fluid therapy is more effective than IV fluid therapy in promoting hydration of colonic contents.
If the large-colon impaction fails to resolve with medical management, surgery can be performed. Generally, the impaction is approached via a ventral midline celiotomy, with the affected portion of the colon gently exteriorized and positioned on a sterile colon tray. An enterotomy then is made in the pelvic flexure and the contents of the colon removed.
Surgery for treatment of cecal impactions requires general anesthesia, a ventral midline celiotomy, isolation of the cecum from the celiotomy site, and removal of the contents of the cecum via an enterotomy. Because impactions have recurred after simple evacuation, the cecum is bypassed with an ileocolostomy.
The prognosis associated with impactions involving the large colon is excellent, with a survival rate of >95%. In contrast, the survival rate associated with cecal impactions remains 50-55%, which may reflect the poor prognosis associated with cecal impactions that develop in hospitalized horses.
In some geographic areas, the offending material may be sand, especially if there is an insufficient amount of pasture grass and the horses are fed on the ground. The sand accumulates in the right dorsal colon and transverse colon. Intermittent signs of abdominal pain may occur due to the weight of the sand in the intestine. More severe signs of pain occur when the impaction occludes the lumen of the transverse colon. Under such circumstances, the colon proximal to the obstruction distends with gas, and the horse may become extremely painful. It may not be possible to distinguish this condition from an intestinal displacement or volvulus. Sand also may be identified in the feces by mixing fecal material with water in a plastic rectal examination sleeve.
Treatment of sand impaction may be either medical or surgical. Medical treatment generally involves intragastric administration of psyllium (400 g/500 kg body wt, daily for 7 days) to purge the sand from the lumen. The psyllium flakes are added to 7.5 L of warm water and rapidly pumped into the stomach. These treatments are accompanied by analgesics as needed and IV fluids to promote movement of fluid into the intestinal lumen.
Surgery via a ventral midline celiotomy is necessary if the sand completely obstructs the lumen of the transverse colon. The left colon is exteriorized on a sterile colon tray, and the sand is removed via an enterotomy. The prognosis is usually good. Problems sometimes develop during surgery if the colon was damaged due to the extensive weight of the sand or while the sand is being removed from the intestine.