History
A 2-year-old male German Shepherd Dog was evaluated because of vomiting of 4 days’ duration. The dog had vomited > 6 times during this period. The patient had been seen 2 days earlier by the referring veterinarian, who had prescribed a bland diet. The vomitus initially consisted of food and then progressed to watery, bile-stained fluid with a fetid odor. The patient had mild diarrhea without evidence of melena or hematochezia. The patient had undergone a jejunal resection and anastomosis 3 weeks previously for mechanical obstruction secondary to foreign body ingestion. The patient had a history of food allergies to some types of grain and poultry.
No abnormalities were detected on abdominal palpation or rectal examination. The patient had mild periorbital and periauricular alopecia that was presumed to be secondary to the reported food allergies. The patient's overall body condition was considered good, with a body condition score of 4 of 9. A CBC revealed a stress leukogram and moderately high Hct. Serum biochemical analysis findings were consistent with dehydration and vomiting with respiratory compensation of metabolic alkalosis (BUN concentration, 53 mg/dL [reference range, 9 to 30 mg/dL]; creatinine concentration, 1.5 mg/dL [reference range, 0.7 to 1.3 mg/dL]; albumin concentration, 4.2 g/dL [reference range, 2.8 to 3.7 g/dL]; Na concentration, 134 mEq/L [reference range, 143 to 152 mEq/L]; K concentration, 3.1 mEq/L [reference range, 3.4 to 4.5 mEq/L]; Cl concentration, 84 mEq/L [reference range, 110 to 119 mEq/L]; CO2 concentration, 26 mEq/L [reference range, 18 to 25 mEq/L]; and anion gap, 27.1 mEq/L [reference range, 12.3 to 18.5 mEq/L]). Results of canine pancreas-specific lipasea and amylase tests were within reference ranges. Radiographs of the abdomen were obtained (Figure 1).
Lateral (A and B) and ventrodorsal (C and D) radiographic views of the abdomen of a 2-year-old sexually intact male German Shepherd Dog with a 2-day history of vomiting.
Citation: Journal of the American Veterinary Medical Association 241, 3; 10.2460/javma.241.3.319
Lateral (A and B) and ventrodorsal (C and D) radiographic views of the abdomen of a 2-year-old sexually intact male German Shepherd Dog with a 2-day history of vomiting.
Citation: Journal of the American Veterinary Medical Association 241, 3; 10.2460/javma.241.3.319
Lateral (A and B) and ventrodorsal (C and D) radiographic views of the abdomen of a 2-year-old sexually intact male German Shepherd Dog with a 2-day history of vomiting.
Citation: Journal of the American Veterinary Medical Association 241, 3; 10.2460/javma.241.3.319
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Diagnostic Imaging Findings and Interpretation
The stomach is moderately distended with gas and fluid (Figure 2). The descending and ascending duodenum, best seen on the left lateral projection, are also severely distended with gas and fluid. The maximum small intestinal diameter measures approximately 2.5 times the minimum height of the L5 vertebral body. The gas within the small intestine is centrally located within the lumen. The remaining small intestine appears fluid filled and normal in diameter. Evidence of a radiopaque foreign body is not seen.
The same lateral radiograph of the cranial aspect of the abdomen as in Figure 1. There is severe fluid and gas dilation of the descending and ascending duodenum (dotted line and white arrows). The descending duodenum diameter measures approximately 2.5 times the height of the L5 vertebral body.
Citation: Journal of the American Veterinary Medical Association 241, 3; 10.2460/javma.241.3.319
The same lateral radiograph of the cranial aspect of the abdomen as in Figure 1. There is severe fluid and gas dilation of the descending and ascending duodenum (dotted line and white arrows). The descending duodenum diameter measures approximately 2.5 times the height of the L5 vertebral body.
Citation: Journal of the American Veterinary Medical Association 241, 3; 10.2460/javma.241.3.319
The same lateral radiograph of the cranial aspect of the abdomen as in Figure 1. There is severe fluid and gas dilation of the descending and ascending duodenum (dotted line and white arrows). The descending duodenum diameter measures approximately 2.5 times the height of the L5 vertebral body.
Citation: Journal of the American Veterinary Medical Association 241, 3; 10.2460/javma.241.3.319
The primary differential diagnosis for the severe segmental ileus was a mechanical obstruction; however, no cause was identified radiographically. Abdominal ultrasonography was performed and confirmed the dilated stomach and duodenum, but a reason for the obstruction was not evident. No other ultrasonographic abnormalities were recognized, so an exploratory laparotomy was performed.
Comments
Radiography is often performed on vomiting animals to rule in conditions requiring surgery, such as mechanical obstruction. The first step in diagnosing mechanical obstruction on radiographs is to detect abnormally dilated small intestine. Small intestine is considered abnormally dilated when the serosa-to-serosa diameter is > 1.6 times the minimum height of the L5 vertebral body.1 Mechanical ileus is usually distinguished from functional ileus on the basis of the presence of a segmental pattern of ileus. With mechanical ileus, the small intestine is typically dilated proximal to an obstruction, with the distal portion of the small intestine appearing normal in diameter. Patients with a functional ileus will most often have generalized dilation. Common rule outs for mechanical ileus include intestinal foreign body, intussusception, intestinal neoplasia, stricture, hernia, volvulus, and adhesions.
Ultrasonography is useful when findings on survey radiographs are not conclusive.2 For the dog of the present report, abdominal radiography and ultrasonography findings were consistent with intestinal obstruction; however, a cause of obstruction was not seen. An exploratory laparotomy was performed; numerous abdominal adhesions, including a strand of fibrous tissue tightly encircling loops of the distal portion of the duodenum and proximal portion of the jejunum and causing an obstruction was found. The strand was excised and removed. A prophylactic incisional gastropexy was performed because of the dog's signalment (ie, deep-chested breed) and gas- and fluid-filled stomach. The dog recovered well after surgery.
In the dog of the present report, a foreign body was not palpable on physical examination. Abdominal radiography may help to support a clinical diagnosis of small intestinal obstruction, which was the case in the dog of the present report. Normal findings on abdominal radiographs do not exclude mechanical obstruction, particularly involving lesions of the proximal portion of the small intestine. Patients with obstructions of the proximal portion of the small intestine may reflux gas and fluid into the stomach, which acts as a reservoir, or gas and fluid may be vomited. These patients may have small intestinal diameters that are within reference limits. When the radiographic diagnosis of a foreign body is uncertain, a gastrointestinal contrast study can be performed. However, these studies are time-consuming and, as a result of persistent vomiting and inadequate contrast volume administered, often nondiagnostic. A barium contrast study to evaluate the proximal portion of the gastrointestinal tract is contraindicated if a perforation is suspected.
In veterinary patients, ultrasonography is replacing the use of radiographic contrast studies in the evaluation of some gastrointestinal tract conditions. Ultrasonography has been shown to be more accurate than plain radiography at diagnosing gastrointestinal obstruction and better at assessing the level of obstruction and the presence of strangulation.3–5 Ultrasonography also provides specific information regarding alterations to the wall of the gastrointestinal tract, including viability. In the patient of the present report, localization of the level of intestinal obstruction on ultrasonography was similar to that on radiography, but no cause of obstruction could be recognized and no other ultrasonographic lesions were appreciated.
Intra-abdominal adhesions are almost inevitable to some extent after major abdominal surgery. Adhesion-related complications, such as intestinal obstruction, have been reported in up to 10% of human patients undergoing laparotomy.6 Dogs and cats have an active fibrinolytic system that usually prevents adhesion formation from becoming a clinical problem after laparotomy. During surgery, a variety of measures are taken to prevent adhesions from developing, including atraumatic tissue handling, minimization of spillage of abdominal contents, and moistening of tissues. If postoperative adhesions do cause an intestinal obstruction, treatment includes surgery with or without intestinal resection and anastomosis.
The dog of the present report was discharged from the hospital 2 days after surgery, and communication with the owners 9 months after surgery revealed no further abdominal problems. Although abdominal adhesions are rarely a problem after surgery in small animals, it should be included as a differential diagnosis for dogs with clinical and imaging signs of gastrointestinal obstruction.
Snap cPL test, IDEXX Laboratories, Westbrook, Me.
1 Graham JP, Lord PF, Harrison JM. Quantitative estimation of intestinal dilation as a predictor of obstruction in the dog. J Small Anim Pract 1998; 39:521–524.
2 Tyrrell D & Beck C. Survey of the use of radiography vs. ultrasonography in the investigation of gastrointestinal foreign bodies in small animals. Vet Radiol Ultrasound 2006; 47:404–408.
3 Ko YT, Lim JH, Lee DH, et al. Small bowel obstruction. Sonographic evaluation. Radiology 1993; 188:649–653.
4 Ogata M, Mateer JR, Condren RE. Prospective evaluation of abdominal sonography for the diagnosis of small bowel obstruction. Ann Surg 1996; 223:237–241.
5 Czechowski J. Conventional radiography and ultrasonography in the diagnosis of small bowel obstruction and strangulation. Acta Radiol 1996; 37:186–189.
6 Schippers E, Tittel A, Ottinger A, et al. Laparoscopy versus laparotomy: comparison of adhesion-formation after bowel resection in a canine model. Dig Surg 1998; 15:145–147.
