History
A 10-week-old female Jersey calf was evaluated because of anorexia of 12 hours’ duration and the presence of a focal swelling on the caudal aspect of the thorax and cranial aspect of the abdomen on the left side. The owner reported no history of trauma. Several calves on the same farm had diarrhea during the season, and a small number had died. Salmonella hindmarsh had been isolated from 2 of these calves, and a vaccination program had commenced. No other calves had developed abdominal or thoracic swellings.
On physical examination, the calf was mildly pyrexic (39.7°C [103.5°F]; reference range, 38.0° to 39.5°C [100.4° to 103.1°F]), tachycardic (128 beats/min; reference range, 72 to 100 beats/min), and tachypneic (112 breaths/min; reference range, 20 to 40 breaths/min). On the left ventral aspect of the abdomen, a 17.0 (craniocaudal dimension) × 20.0 (dorsoventral dimension) × 2.5-cm (thickness), nonpainful, fluctuant swelling was present. The swelling extended from the 9th to 13th rib and from the sternum approximately 20 cm dorsally. No evidence of bruising was identified. The calf received treatment for pyrexia of unknown origin.
On the third day of hospitalization, the calf developed melena and bruxism. A brief ultrasonographic examination performed by the clinical service identified the swelling as a fluid pocket, but the origin could not be determined. Fine-needle aspirates of the swelling yielded fluid that grossly resembled gastric content. No protozoa were identified microscopically to confirm a ruminal origin. Helical CT of the abdomen was performed.a Images were acquired at the level of the eighth thoracic to second coccygeal vertebrae with the patient in dorsal recumbency. The calf was sedated prior to CT with xylazine (0.2 mg/kg [0.09 mg/lb], IM). The CT images were obtained before and after IV administration of 120 mL of iohexol solution (350 mg/mL) and reconstructed in bone and soft tissue algorithms. Postcontrast CT images of the abdomen in a soft tissue algorithm are shown (Figure 1).
Postcontrast axial CT images of the abdomen of a 10-week-old female Jersey calf with anorexia of 12 hours’ duration and a focal swelling on the left caudal aspect of the thorax and cranial aspect of the abdomen. Images were reconstructed in a soft tissue algorithm (window width, 233 Hounsfield units [HU]; window level, 44 HU) at the level of T13 (A), L3 (B), the cranial aspect of L5 (C), and the caudal aspect of L5 (D). Image acquisition parameters were 120 kV, 300 mA, 1.4 pitch (ratio), and 3-mm slice thickness.
Citation: Journal of the American Veterinary Medical Association 248, 10; 10.2460/javma.248.10.1117
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Diagnostic Imaging Findings and Interpretation
On CT images, the left caudoventral aspect of the abdominal wall is moderately enlarged (approx 17.0 × 2.5 cm) and expanded by a moderate volume of a mixture of fat and fluid (−35 Hounsfield units [HU]) and gas (−692 HU) attenuations and a small volume of amorphous mineral (100 HU) attenuation (Figure 2). As a point of reference, typical HU values for CT are the following: gas, −1,000 HU; fat, −100 to −50 HU; water, 0 HU; CSF 15 HU; blood, 30 to 45 HU; liver, 40 to 60 HU; trabecular bone, 700 HU; and cortical bone, 3,000 HU.
Same CT images as in Figure 1. A—Notice the swelling of the left caudoventral aspect of the abdominal wall (thick arrow) with dissecting gas (thin arrows), mineral within the lamina of the omasum, and a floating foreign body (arrowhead) within the ventral compartment of the rumen. B—A fluid line is present within the subcutaneous swelling (thin arrow), with free peritoneal gas (thick arrows). Folds are visible within the abomasum, which is displaced on the left between the rumen and body wall. C—Fluid and gas dissect caudally within the subcutaneous tissues (thin arrow), with free peritoneal gas (thick arrows) and a defect within the pyloric part of the abomasum communicating with the peritoneal space (asterisk). D—Free peritoneal gas is again noted (thick arrows), and the subcutaneous fluid (thin arrow) communicates with the pyloric part of the abomasum through a large defect (asterisk) on the left side. a = Abomasum. o = Omasum. p = Pylorus. rdc = Dorsal compartment of rumen. rvc = Ventral compartment of rumen.
Citation: Journal of the American Veterinary Medical Association 248, 10; 10.2460/javma.248.10.1117
A meniscus sign is present at the gas-fluid interface within the swelling, consistent with positioning of the patient in dorsal recumbency. The swelling extends cranially to the level of the sternum and caudally to the flank, dissecting through the subcutaneous tissue. The peripheral internal soft tissue margins of the swelling are mildly irregular. At the medial aspect of the swelling, a 3.0 × 1.6-cm defect is present that communicates with the lumen of the abomasum. The abomasum and omasum are displaced laterally to the left, lying between the dorsal and ventral sacs of the rumen medially and the left body wall laterally. A second defect in the medial caudoventral aspect of the wall of the abomasum communicates with the peritoneal space, which contains a large volume of gas and a small volume of fluid attenuation (Figure 3). Within the ventral sac of the rumen, a nondependent (buoyant), 2.8-cm, ovoid, fat-attenuating (HU, −128 to −200) structure is present. Within the rumen, reticulum, and omasum, a small volume of amorphous mineral attenuating debris is present.
Dorsal plane reconstructed CT image at the level of the abomasal-subcutaneous fistula in the calf of Figure 1. Fluid dissects within the left subcutaneous tissues (thin arrows), communicating with abomasum and peritoneal space (thick arrows). Notice the position of the abomasum on the left side displacing the rumen from the body wall.
Citation: Journal of the American Veterinary Medical Association 248, 10; 10.2460/javma.248.10.1117
Findings were consistent with abomasal ulceration, pneumoperitoneum, peritoneal effusion, left abomasal and omasal displacement, and a left-sided abomasal-subcutaneous fistula with cellulitis. The foreign body within the rumen was suspected to be a trichobezoar on the basis of its nondependent location within the ruminal fluid (Figure 2).
Treatment and Outcome
The calf was anesthetized, and a midline celiotomy was performed. A single large abomasal ulcer was identified that was adhered to the abdominal wall on the left side. The adhesions were manually broken down, and the abomasal ulcer was inverted and repaired. No other abomasal defects were found during surgery. Gross contamination of the abdominal cavity was removed, and the abdominal cavity was lavaged. At the end of surgery, an indwelling sealed peritoneal drainage system was placed in the peritoneal space.
Antimicrobials and meloxicam were administered daily. On the first day after surgery, the calf had a good appetite, produced normal feces, and had an improved demeanor. The calf subsequently developed melena and signs of pain (eg, bruxism and respiratory grunts), with progressive abdominal distention. On the second day after surgery, the calf developed regurgitation, and aspiration pneumonia was suspected on the basis of findings on thoracic auscultation (ie, increased bronchovesicular sounds). Fluid from the peritoneal drain at this time point was straw colored and contained a small amount of fibrin. Feces were mucus covered but of normal consistency. The patient died later that evening.
On necropsy, gastrointestinal contents were found within the peritoneal cavity. The abomasal surgical site was intact. The swelling on the left caudoventral aspect of the abdominal wall was dissected; abomasal content was found along the ribs and fascial planes of the intercostal, transversus abdominis, and rectus abdominis muscles. The surfaces of the cavity within the abdominal wall were thickened and erythematous with extensive fibrin deposition. A trichobezoar was identified within the rumen. There was no gross evidence of aspiration pneumonia.
Comments
This report describes an abomasal-subcutaneous fistula secondary to abomasal displacement and ulceration in a calf.
Abomasal ulcers are most commonly seen in calves < 8 weeks of age and are typically located in the pyloric region.1 Causes of mucosal ulceration include mechanical damage by rough feeds, abomasal trichobezoars, stress, decreased abomasal pH, mycosis, and dietary imbalances such as selenium deficiency.1 A reported 32% to 76% of healthy veal calves and 0.2% to 5.7% of beef calves develop abomasal ulcers but lack clinical signs.1 Because of the absence of clinical signs in many patients, a definitive diagnosis is often not made without an antemortem exploratory laparotomy or necropsy.1
Several causes of abomasal-subcutaneous fistulae have been reported for calves, including congenital defects and left abomasal displacement and ulceration.2,3 The clinical history and imaging findings in the case described in the present report are most consistent with left abomasal displacement and ulceration as the inciting cause of an acquired abomasal-subcutaneous fistula.
In human medicine, acquired gastrointestinal fistulae can be classified as external (cutaneous) if they drain onto the skin surface and internal if they involve the gastrointestinal system (intestinal) or another organ system (extraintestinal).4 Although contrast radiography, fluoroscopy, and fistulography remain the standard diagnostic methods, CT is often used to provide additional information in human patients with gastrointestinal fistulae.4 Compared with conventional radiography, CT is more sensitive in detecting gas in the peritoneal cavity, which can be an indicator of gastrointestinal perforation.5
Ultrasonography can be useful in the detection of left displaced abomasum in adult cattle.6 Described ultrasonographic findings include medial displacement of the rumen by the abomasum, with decreased visualization of the left ruminal longitudinal groove in the midabdomen, and identification of a dorsally located abomasal gas cap at the level of the 9th to 12th intercostal spaces.6 Identification of fluid or fibrin adjacent to the abomasum can provide corroborative evidence for abomasal perforating ulceration.6 In the calf of the present report, definitive ultrasonographic localization of the origin of the flank swelling was not possible.
For the calf of the present report, CT provided excellent anatomic detail, allowed discrimination of the origin of the swelling, and allowed visualization of gastric compartment displacement and the presence of abomasal ulceration and perforation. Although availability of CT remains limited in veterinary medicine, it may be a useful modality for investigation of gastrointestinal disease in calves.
Footnotes
Philips Brilliance 16-slice multidetector helical CT scanner, Philips Healthcare, Eindhoven, The Netherlands.
References
1. Marshall TS. Abomasal ulceration and tympany of calves. Vet Clin North Am Food Anim Pract 2009; 25: 209–220.
2. Mueller K, Merrall M, Sargison ND. Left abomasal displacement and ulceration with perforation of abdominal musculature in two calves. Vet J 1999; 157: 95–97.
3. Sharma A, Upadhye SV, Kour K. Congenital abomasal fistula in a buffalo calf and its successful treatment. Buffalo Bulletin 2011; 30: 1–3.
4. Pickhardt PJ, Bhalla S, Balfe DM. Acquired gastrointestinal fistulas: classification, etiologies, and imaging evaluation. Radiology 2002; 224: 9–23.
5. Zhonghua S, Al-Naami A, Ligat AK. Perforated duodenal ulcer associated with anterior abdominal abscess: a case report. Australas Med J 2012; 5: 14–17.
6. Streeter RN, Step DL. Diagnostic ultrasonography in ruminants. Vet Clin North Am Food Anim Pract 2007; 23: 541–574.
