Figure 6.8 Resected segment of intestine submitted for histopathologic analysis from a four‐year‐old, male castrated Shih Tzu that was evaluated for an acute onset of vomiting, lethargy, and anorexia for three days and a one‐day history of hematochezia. The dog was diagnosed with an intussusception based on physical examination and an abdominal ultrasound. At surgery, an approximately 10‐cm segment of jejunum was invaginated upon itself. A resection and anastomosis was performed. Final histopathology revealed mild lymphoplasmacytic enteritis, but no masses or apparent cause for the intussusception.

      Source: Reproduced with permission from T. Donovan.

Following removal of the resected section of intestine, it is advisable to submit the section for histological examination (Figure 6.8). In a study of the histopathology reports of 49 animals (31 dogs and 18 cats) with intussusception, histopathology was able to detect abnormalities that may have contributed to intussusception in 47% of cases [39]. If biopsy specimens from additional segments of bowel (other than the resected segment) were also submitted, a potential contributing histological finding was documented in 85% of patients. The most common underlying abnormality in dogs was found to be inflammatory disease, while cats were significantly more likely to have neoplastic lesions [39].

Postoperative Care and Complications

      Following surgery, patients should be closely monitored with respect to hydration, perfusion, comfort level, electrolyte and acid–base status. Electrolytes and acid–base parameters should be evaluated once daily, and potentially more frequently, depending on the degree of derangements preoperatively. Opioid analgesia is important not only for patient comfort but may play a role in preventing reoccurrence of intussusception. In a study of dogs undergoing renal transplantation, the rates of intussusception dropped from 17% to 3% in dogs receiving butorphanol in the postoperative period [40]. It is hypothesized that opioids increase the tone of the intestines, as well as the amplitude of the non‐propulsive contractions that may decrease local bowel wall inhomogeneity and segmental ileus [41]. Patients may experience nausea and regurgitation postoperatively, which can be managed with antiemetics and gastric acid reducers, such as proton pump inhibitors (pantoprazole, esomeprazole, omeprazole) or H2‐blockers (famotidine). Prokinetic agents, such as metoclopramide and erythromycin or azithromycin, should be considered if ileus and enteral feeding intolerance are suspected or documented.

      Initiation of feeding is begun as patients are alert and awake, usually within 12 hours following surgery. A significant number of dogs with gastroesophageal intussusception may have persistent regurgitation and significant esophageal dilation following repair, which may require elevated feeding [8]. In debilitated patients, or those remaining anorectic, nutritional support should be provided. Early enteral nutrition (within 24 hours of surgery) in children undergoing GI resection was associated with lower rates of complications, shorter hospitalization time and quicker postoperative GI function recovery [42]. This has not been corroborated in dogs, but studies did report on benefits of early enteral nutrition (within 48 hours of admission) in dogs with pancreatitis where it has been shown to decrease GI intolerance and expedite voluntary intake in dogs with pancreatitis [43]. A nasogastric tube is the least invasive method of enteral nutrition that does not require anesthesia for placement and may be a simple way of providing the patient's nutritional needs during convalescence. Other options include esophagostomy, gastrostomy, or enterostomy tubes (see Chapter 21, Feeding tubes). Ideally, placement of a feeding tube should be considered at the time of the initial surgery, depending on the patient's nutritional status, healing potential, and appearance of the GI tract at surgery. Parenteral nutrition should be considered in patients who have refractory enteral feeding intolerance or in those who are severely malnourished and may have delayed ability to achieve full resting energy requirements solely via enteral route. Important surgical complications to monitor for include dehiscence, peritonitis, and short‐bowel syndrome if a large portion of intestine is resected, as well as reoccurrence of intussusception or obstruction secondary to enteroplication [41].

Prognosis

      Prognosis is favorable following uncomplicated reduction or resection. Reoccurrence rates range from 3% to 27% [2, 21] and are usually noted within three days of surgery but have been reported to occur up to three weeks following the procedure in dogs and 12 months after the initial surgery in cats [2, 7]. It appears that reoccurrence may be more frequent in patients undergoing manual reduction rather than resection and anastomosis but no other specific risk factors for reoccurrence have been identified [21]. Persistent regurgitation may occur in animals with gastroesophageal intussusception, in part because of megaesophagus, and adjustments to the feeding regimen may be required to decrease the chance of aspiration. Treatment for any underlying disease process identified should be addressed to minimize reoccurrence of intussusception. Enteroplication may diminish this risk but is not without the potential for serious complications.