History
A 5-year-old 28-kg (61-lb) neutered male Standard Poodle was evaluated because of an acute onset of vomiting, diarrhea, and hyporexia. The dog was receiving prednisone, mycophenolate, and cyclosporine for immune-mediated thrombocytopenia, which had been diagnosed 1 year earlier. The dog's vital signs were within reference ranges, and physical examination revealed mild dehydration and a distended abdomen. A CBC indicated mild anemia (Hct, 28.9%; reference range, 37.3% to 61.7%) and moderate thrombocytopenia (90,000 platelets/μL; reference range, 148,000 to 484,000 platelets/μL). Slightly high alkaline phosphatase (618 U/L; reference range, 23 to 212 U/L), γ-glutamyltransferase (55 U/L; reference range, 0 to 11 U/L), and lipase (2,016 U/L; reference range, 200 to 1,800 U/L) activities were detected on serum biochemical analysis. No free abdominal fluid was observed on a focused abdominal ultrasonographic evaluation (ie, FAST [fast assessment with sonography for trauma]). Survey abdominal radiographs were subsequently taken (Figure 1).
Right lateral (A) and ventrodorsal (B) radiographic views of a 5-year-old 28-kg (61-lb) neutered male Standard Poodle with an acute history of vomiting, diarrhea, and hyporexia.
Citation: Journal of the American Veterinary Medical Association 251, 1; 10.2460/javma.251.1.37
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Radiographic Findings and Interpretation
The liver is mildly to moderately enlarged. The spleen appears of normal size with unusual folding of the body of the spleen within the left cranial portion of the abdomen. The stomach contains a small amount of gas. Most of the small intestine contains small amounts of fluid and gas and is of normal diameter. A segment of intestine within the right cranial to mid aspect of the abdomen, most consistent with small intestine, has extensive, linear gas opacities within the intestinal wall (Figure 2). Thoracic radiography was also performed (images not shown), and no abnormalities were detected.
Same radiographic images as in Figure 1. Notice the well-defined, irregularly shaped, radiolucent gas inclusions within a small intestinal segment in the right cranial to mid aspect of the abdomen (arrows).
Citation: Journal of the American Veterinary Medical Association 251, 1; 10.2460/javma.251.1.37
Abdominal ultrasonography was subsequently performed, which revealed numerous hyperechogenic intramural lesions that caused a reverberation artifact within the mucosal layer of the small intestinal wall (Figure 3). Findings on abdominal radiography and ultrasonography were indicative of pneumatosis intestinalis.
Transverse ultrasonographic image of the abdomen of the dog in Figure 1. Notice a segment of small intestine with a focal area of hyperechogenicity (arrow) with associated reverberation artifact within the mucosal layer, indicating the intramural presence of gas. This area is distinct to the intraluminal gas surrounding it. The image was obtained transabdominally with a 3- to 6-MHz linear transducer.
Citation: Journal of the American Veterinary Medical Association 251, 1; 10.2460/javma.251.1.37
Treatment and Outcome
The dog was hospitalized and treated with IV fluids and gastroprotectant drugs, including maropitant, famotidine, and sucralfate. Antimicrobial treatment was instituted with metronidazole and enrofloxacin. Treatment with immunosuppressive drugs was continued with dexamethasone, cyclosporine, and mycophenolate. On the following day, the dog's appetite had greatly improved, and abdominal radiography was repeated, which revealed radiographic resolution of the pneumatosis intestinalis. The dog was discharged from the hospital 3 days after admission to receive a 2-week course of metronidazole (10 mg/kg [4.54 mg/lb], PO, q 12 h) and enrofloxacin (10 mg/kg, PO, q 24 h). At a 6-month follow-up examination, the dog was found to be in good health with no known relapses.
Comments
Gastrointestinal pneumatosis is a rare condition characterized by the presence of gas within the wall of the gastrointestinal tract or portomesenteric vasculature, with variations dependent on the anatomic location of the gas (ie, gastric pneumatosis, pneumatosis intestinalis, and pneumatosis coli). Gastric pneumatosis has been described in a cat following laparotomy to remove multiple intestinal foreign bodies, and has been reported to occur in dogs with gastric dilatation-volvulus syndrome.1,2 To our knowledge, only 1 report3 has been published describing pneumatosis intestinalis in a dog; however, in that report, the dog died of cardiac arrest soon after hospital admission as a result of concurrent illness. Dogs affected with pneumatosis coli generally respond well to supportive and medical treatments and survive to hospital discharge.4,5
Two main theories attempt to explain the etiology of gastrointestinal pneumatosis, proposing either a bacterial or a mechanical origin for the disease. The bacterial model suggests bacterial infiltration across the mucosa or submucosa, resulting in intramural gas production. This theory is supported by the presence of hydrogen gas—an indicator of anaerobic bacterial activity—within intestinal wall cysts as well as high breath hydrogen concentrations in patients with pneumatosis intestinalis.6 The mechanical theory describes the dissection of gas into the intestinal wall from either the mediastinum or intestinal lumen as a result of an increase in pressure. Conditions such as emphysema, intestinal obstruction, vomiting, and diarrhea are believed to contribute to the development of gastrointestinal pneumatosis by the mechanical theory.7
Lesions associated with gastrointestinal pneumatosis are typically readily apparent on radiographic or ultrasonographic studies, although abdominal CT has been shown to be the gold standard imaging modality in people.7,8 Care must be taken when interpreting radiographs alone, as pneumatosis lesions may appear similar to those of a gas-trapping foreign body.
In human patients with gastrointestinal pneumatosis, treatment relies largely on supportive care and surgical resection if necessary8 Treatment recommendations for gastrointestinal pneumatosis in the veterinary literature include resolution of the primary inciting cause, gastrointestinal and nutritional support, and potentially antimicrobial treatment that includes anaerobic coverage.1,2,4,5
To our knowledge, the case described in the present report is the only report of pneumatosis intestinalis in a dog that survived to hospital discharge. The extremely rapid resolution of both the clinical signs and radiographic findings suggest that the inciting cause of the pneumatosis intestinalis was addressed in a timely fashion before deleterious secondary effects occurred. Possible causes for the dog's condition included acute gastroenteritis, corticosteroid administration, and anaerobic bacterial overgrowth.
References
1. Lang LG, Greatting HH, Spaulding KA. Imaging diagnosis—gastric pneumatosis in a cat. Vet Radiol Ultrasound 2011; 52:658–660.
2. Fischetti AJ, Saunders HM, Drobatz KJ. Pneumatosis in canine gastric dilatation-volvulus syndrome. Vet Radiol Ultrasound 2004; 45:205–209.
3. Song YM, Lee JY, Lee JW, et al. Ultrasonographic findings of pneumatosis intestinalis in a dog. J Vet Clin 2013; 30:138–141.
4. Aste G, Boari A, Guglielmini C. What is your diagnosis? Pneumatosis coli. J Am Vet Med Assoc 2005; 227:1407–1408.
5. Russell NJ, Tyrell D, Irwin PJ, et al. Pneumatosis coli in a dog. J Am Anim Hosp Assoc 2008; 44:32–35.
6. Togawa S, Yamami N, Nakayama H, et al. Evaluation of HBO2 in pneumatosis cystoides intestinalis. Undersea Hyperb Med 2004; 31:387–393.
7. Ho LM, Paulson EK, Thompson WM. Pneumatosis intestinalis in the adult: benign to life-threatening causes. AJR Am J Roentgenol 2007; 188:1604–1613.
8. Hoot NR, Pfennig CL, Johnston MN, et al. An incidental finding? Pneumatosis intestinalis after minor trauma. J Emerg Med 2013; 44:e145–e147
