History
An 8-year-old 54-kg (119-lb) sexually intact male Redbone Coonhound was evaluated for a 2-day history of abdominal distension, vomiting, diarrhea, and lethargy. The dog had no history of trauma.
On physical examination, the dog was bright, alert, and responsive. The dog was tachypneic and had an increase in respiratory effort, abdominal distension, and markedly enlarged superficial cervical lymph nodes. No other abnormalities were detected on the remainder of the physical examination. Initial diagnostic testing revealed a PCV of 38% (reference range, 37% to 55%) and a plasma total protein concentration of 7.5 g/dL (reference range, 5.5 to 7.7 g/dL). Additional findings included hyperglycemia (181 mg/dL; reference range, 76 to 116 mg/dL) and hyperlactatemia (3.0 mmol/L; reference range, 0.5 to 2.5 mmol/L). The mean systolic blood pressure was 134 mm Hg (reference range, 110 to 170 mm Hg), and the dog had a normal sinus rhythm on ECG. An abdominal FAST (focused assessment with sonography for trauma) scan revealed a small amount of anechoic peritoneal fluid. Abdominal and thoracic radiography was performed to investigate the cause of the abdominal distension (Figure 1).
Left lateral (A), right lateral (B), and dorsoventral (C) radiographic images of the abdomen of an 8-year-old sexually intact male Redbone Coonhound evaluated because of abdominal distension, vomiting, diarrhea, and lethargy.
Citation: Journal of the American Veterinary Medical Association 251, 5; 10.2460/javma.251.5.507
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Diagnostic Imaging Findings and Interpretation
The colon is markedly gas distended and malpositioned. The transverse colon is located in the caudal aspect of the abdomen with the descending colon extending cranially in the right side of the abdomen and the ascending colon extending cranially in the left side of the abdomen (Figure 2). The caudal portion of the descending colon is empty and not visible. The cecum is displaced into the left cranial aspect of the abdomen and is visible as a large-diameter gas-distended C-shaped structure. Additionally, there are multiple gas-distended loops of small intestine in the dorsal aspect of the peritoneal cavity just caudal to the stomach. There is a mild decrease in peritoneal serosal detail consistent with a mild amount of abdominal effusion. The retroperitoneal serosal detail is adequate. No evidence of free peritoneal gas is identified. The stomach is mildly distended with gas. The spleen is not visualized. No abnormalities of the kidneys or bladder are evident.
Same radiographic images as in Figure 1. Notice the colon is markedly gas distended and malpositioned. The transverse colon (T) is located in the caudal aspect of the abdomen with the descending colon (D) extending cranially in the right side of the abdomen and the ascending colon (asterisk) extending cranially in the left side of the abdomen. The cecum is located in the left cranial portion of the abdomen (C).
Citation: Journal of the American Veterinary Medical Association 251, 5; 10.2460/javma.251.5.507
The radiographic findings are most consistent with a colonic volvulus. Additional differential diagnoses for a severely gas-distended colon include colitis, typhlitis, intussusception, and cecal inversion; however, these were considered less likely because of the abnormal positioning of the colon on radiographic images and lack of corresponding clinical signs. Colonic distension secondary to causes of mechanical obstruction such as sublumbar lymphadenopathy, prostatomegaly, paraprostatic cyst, intrapelvic mass, or colonic or rectal neoplasia was considered less likely because of lack of colonic fecal distension, the malpositioning of the colon, and lack of a mass effect on radiographic images. Neurologic causes of colonic distension were also considered less likely because of lack of corresponding history or clinical signs.
Treatment and Outcome
Given the radiographic findings suggestive of colonic volvulus, immediate exploratory laparotomy was recommended.
Results of preanesthetic CBC and serum biochemical analysis revealed lymphopenia (0.9 × 103 cells/μL; reference range, 1.5 × 103 cells/μL to 5.0 × 103 cells/μL); anemia (Hct, 32.1%; reference range, 37% to 55%); hyperlactatemia (3.2 mmol/L; reference range, 0.5 to 2.5 mmol/L); hyponatremia (142.7 mmol/L; reference range, 145 to 151 mmol/L), and hypochloremia (106.9 mmol/L; reference range, 110 to 119 mmol/L).
An exploratory laparotomy was performed via a standard midline approach. The colon was identified; it was segmentally distended and mildly reddened without petechiation. The colon was partially decompressed by use of 23 and 20 gauge needles and active suction. The colon was found to have a 180° counterclockwise volvulus and a small degree of torsional rotation. The volvulus was corrected via a clockwise derotation. The small intestine appeared distended and moderately discolored with petechiation noted within the mesentery; however, the color of the small intestine improved following correction of the colonic volvulus. Additional surgical findings included a splenic mass measuring 6.0 cm in diameter that was dark red to brown and smoothly marginated and distorted the splenic capsule. The spleen was removed and placed in neutral-buffered 10% formalin to be submitted for histologic examination. An incisional colopexy and gastropexy were performed prior to closing the abdomen.
A sample of peritoneal effusion was collected during surgery for bacteriologic culture and antimicrobial susceptibility testing. Results of aerobic and anaerobic bacteriologic cultures were negative. Cytologic examination of the peritoneal effusion revealed a purulent exudate with no infectious organisms identified. Histologic examination of the splenic mass revealed a complex nodular hyperplasia with a focal subcapsular hematoma and no evidence of a neoplastic process. The enlarged superficial cervical lymph nodes identified on physical examination were aspirated and cytologic findings were most consistent with lymphoid hyperplasia, which was suspected to be secondary to chronic large bilateral elbow hygromas as no other potential causes were identified.
The patient was hypotensive during surgery and had a substantial amount of blood loss. Supportive fluid therapy, a vasopressor (dopamine), and atropine were administered intraoperatively. A transfusion of packed RBCs (500 mL) was administered after surgery to compensate for ongoing blood loss. The patient continued to be hypotensive after surgery, and was also hypothermic and tachycardic. Additionally, after surgery the dog had moderate hypoalbuminemia (1.3 g/dL; reference range, 3.0 to 4.3 g/dL), which was thought to be the cause of the persistent hypotension. An infusion of canine albumin (25 g) was given that resulted in a substantial increase in the serum albumin concentration (2.4 g/dL; reference range, 3.0 to 4.3 g/dL). The blood pressure and heart rate consequently normalized and the patient became much more alert. With active warming, the hypothermia resolved a few hours after surgery. The patient's condition gradually improved until hospital discharge 6 days after admittance. The dog was doing well 1 month after surgery without any evidence of recurrence.
Comments
This report describes a case of acute large intestinal volvulus in an 8-year-old sexually intact male Redbone Coonhound. The signalment of this patient is consistent with previous cases suggesting that young to middle-aged, medium to large breed male dogs have a predisposition for intestinal torsion and volvulus.1–5 An intestinal torsion is defined as the twisting of a segment of intestine along its long axis. This is in contrast to an intestinal volvulus, which involves a segment of intestine rotating around its mesenteric axis.1–5 Intestinal volvulus and torsion may occur simultaneously. Either of these conditions can lead to a partial or complete obstruction of the affected segment's vascular supply, causing a cascading series of events ultimately resulting in endotoxemia and cardiovascular failure.1,2,4
The frequency at which large intestinal torsion and volvulus occurs in dogs is exceedingly rare.5 To date the exact etiology in dogs is unknown; however, it has been correlated with multiple preexisting conditions including, but not limited to, a previous history of gastric dilatation-volvulus, closed abdominal trauma, gastrointestinal disease, and exocrine pancreatic insufficiency.1,3,4 Findings in a retrospective study on predisposing factors for colonic torsion and volvulus in 6 dogs found that 4 dogs had a history of previous gastric dilatation-volvulus with surgical correction and right-sided gastropexy.1 It was found that of the 4 dogs with a history of gastric dilatation-volvulus, 3 had entrapment of the large intestine around the gastropexy sites.1 Suggested causes for the entrapment of the large intestine included rupture of the duodenocolic ligament or the presence of intestinal adhesions.1 To our knowledge the patient in the present report did not have any of these preexisting conditions including a previous gastropexy.
The clinical signs seen in the dog of the present report, including acute vomiting, abdominal distension, and lethargy, were consistent with previously reported cases.1,4,5 Other commonly reported clinical signs of colonic volvulus include pain, recumbency, tympany, tenesmus, and hypovolemic shock.1,4,5 None of these signs are pathognomonic for colonic torsion and volvulus, making the diagnosis difficult. Diagnostic imaging, particularly abdominal radiography, is an important diagnostic tool; typical radiographic findings for intestinal torsion and volvulus include generalized decrease in serosal margin detail and intestinal dilatation and malpositioning.6 Other reported procedures for diagnosis of colonic torsion and volvulus include barium enema and colonoscopy.2 In the patient of the present report, survey radiographic findings including colonic malpositioning and associated severe gas distension were highly suggestive of colonic volvulus and additional diagnostic testing was determined to be unnecessary prior to surgical intervention.
The treatment protocol for colonic torsion and volvulus includes fluid resuscitation (if the patient is cardiovascularly unstable), administration of antimicrobials and analgesics, and exploratory laparotomy.7 Intraoperative decompression of distended intestine is suggested to help with colonic derotation and assessment of intestinal viability.7 A colopexy is recommended to prevent reoccurrence; however, the rate of recurrence has not been studied.7,8
When diagnosis is delayed, a high mortality rate has been associated with colonic torsion and volvulus in dogs.1–5 Therefore, immediate exploratory laparotomy is the treatment of choice if a colonic torsion and volvulus is suspected on the basis of clinical signs and diagnostic imaging findings.
The recognition of a markedly dilated and malpositioned colon on radiographic images of the patient of the present report facilitated the diagnosis of a colonic volvulus and allowed for expedited surgical intervention. Although the patient had a prolonged recovery from surgery, ultimately the outcome was successful.
Acknowledgments
No support was received for this manuscript, and the authors declare that there were no conflicts of interest.
References
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