Intestinal obstruction - intestinal foreign bodies, intussusception, and intestinal torsion
Small intestinal obstruction most often results from foreign bodies such as peach pits, corn cobs, toys, and fish hooks in dogs and linear foreign bodies in cats. Other differential diagnoses for intestinal obstruction include intussusception, intestinal torsion, and neoplasia.
The clinical findings of intestinal obstruction are related to the site, severity, and cause of the obstruction. Complete upper intestinal obstruction results in severe acute vomiting, which is associated with fluid loss and dehydration and, if left untreated, can lead to circulatory shock. Partial obstructions can be more challenging to diagnose, as they often present with an insidious onset of vomiting and intermittent chronic diarrhea. The history is sometimes helpful in raising the suspicion of a foreign body. Intussusceptions are commonly seen in young animals, particularly in conjunction with severe acute enteritis, such as parvovirus infection (Figure 5.9) or ascarid infestation, but can also be seen in cases of chronic diarrhea, such as IBD.74 Intestinal neoplasia (see5.3.10 and 9.3) is more commonly seen in middle-aged to older animals, but single lymphoma lesions can also be seen in young patients, particularly in cats. Intestinal torsion (volvulus) is a rare disorder in dogs, which involves intestinal rotation at the root of the mesentery, with complete occlusion of the cranial mesenteric artery. This results in bowel necrosis, release of toxins and life-threatening shock. Most cases have been reported in adult, medium to large breed male dogs.75
A thorough physical examination is important in all cases, which includes a meticulous examination of the base of the tongue for linear foreign bodies, especially in cats. Abdominal palpation sometimes reveals the site of intestinal obstruction. Immediate radiographic and/or ultrasonographic examination is also indicated (see 1.3). Complete intestinal obstruction and intestinal volvulus are readily visible on abdominal radiographs by the presence of diffusely distended bowel loops. It is important to identify signs of a possible bowel perforation, such as decreased serosal detail and free abdominal gas. A minimum blood chemistry database to characterize the fluid and electrolyte losses should be performed and fluid therapy should be initiated before exploratory laparotomy.
Treatment of intestinal obstruction involves removal or resection of the cause of the obstruction. Antibiotics should be given to patients with signs of intestinal perforation or those at risk of intestinal bacterial translocation. Antibiotic protocols vary, but one example is the combination of ampicillin and metronidazole. The prognosis depends on the cause of obstruction and the severity of complications associated with it. For intestinal volvulus, the prognosis is usually grave unless immediate exploratory laparotomy is performed.75
5.3.5