Abstract

Gastrointestinal strictures are characterized by an abnormal narrowing of the intestinal lumen due to cicatricial tissue resulting in an accumulation of gastrointestinal contents, partial or complete obstruction, and subsequent dilation or diverticulum formation proximal to the stricture.^1,3 Intestinal strictures caused by neoplasia have been previously reported in a corn snake (Elaphe guttata guttata) and a green sea turtle (Chelonia mydas); otherwise, strictures are infrequently documented in reptiles.^2,4

Intestinal or cloacal strictures resulting in gastrointestinal obstruction were diagnosed in six green sea turtles from three rehabilitation facilities and two zoological parks. The exact cause for the intestinal or cloacal strictures in the cases reported here are unknown but are likely multifactorial, and etiologies are likely to be different between the free-ranging and aquarium-maintained green sea turtles. Anatomical adaptations of the gastrointestinal tract unique to the green turtle's herbivorous diet, paired with causes of reduced intestinal motility, and exposure to a wide range of foreign bodies in the environment may predispose the species to intestinal damage and subsequent obstructive intestinal disease, such as strictures or intestinal volvulus. In aquarium-maintained green turtles, inappropriate diet, enterocolitis, cloacitis, obesity, and neurological disorders acquired from previous traumatic events might also be considered potential contributing factors.

Clinical, radiographic, and hematological abnormalities common among most of these sea turtles include: positive buoyancy, lethargy, inappetence, regurgitation, obstipation, radiographic evidence of ileus and distended bowel, anemia, hypoglycemia, hypoalbuminemia, hypocalcemia, and elevated creatine kinase, aspartate aminotransferase, and blood urea nitrogen. Although these abnormalities are nonspecific with many possible contributing factors, gastrointestinal disease including strictures should be considered a differential in wild and aquarium-maintained green sea turtles demonstrating all or a combination of these clinical findings.

Lower gastrointestinal contrast studies were successfully performed in two cases by instilling the contrast rectally via endoscope. This technique was useful in identifying the exact location of obstruction. While diagnostic imaging including radiographs, computed tomography, or magnetic resonance imaging are important in determining a cause for suspected gastrointestinal disease and identifying an anatomical location of obstruction, intestinal strictures were not identified utilizing these imaging modalities. Adjusting slice thickness, three-dimensional reconstruction, and utilizing contrast might enhance detection in some cases. This underlines the importance of other modalities such as colonoscopy and exploratory coeliotomy in cases where commonly used imaging techniques do not lead to a definitive diagnosis. Colonoscopy was important in acquiring further clinical information in cases where the obstruction was located in the distal portion of the intestinal tract and was instrumental in visually diagnosing intestinal stricture in one case.

Identification of intestinal strictures, when possible, might improve surgical planning and prognosis. While partial strictures of the cloacal opening may be identified grossly and managed with appropriate medical treatment, surgical intervention or humane euthanasia are likely the only options for sea turtles once small or large intestinal strictures have formed. Medical therapy, although palliative for a time in some instances, ultimately was not successful for these described cases so surgical intervention was pursued; however, the surgeries were difficult or unsuccessful due to severe preexisting gastrointestinal adhesions.

Acknowledgements

The authors thank the Georgia Sea Turtle Center, Disney's Animal Science and Environmental Line of Business, the University of Florida College of Veterinary Medicine, North Carolina State University College of Veterinary Medicine, the Karen Beasley Sea Turtle Rescue and Rehabilitation Center, Mote Marine Laboratory Sea Turtle Rehabilitation Hospital, and Minnesota Zoological Gardens for sharing their cases. The authors thank Drs. Andrew Jackson, James F. Wellehan, Jr., Alexander E. Gallagher, David J. Reese, and Paige Brock for their clinical and surgical assistance, and pathologists Drs. Scott Terrell, Nancy L. Stedman, William L. Castleman, Arno Wünschmann, and Anibal G. Armien for their histological examination of the cases. The authors also thank Steven Nelson, Sarah Purcell, Pia Oresjo, Patrick Thompson, Jane Capobianco, Lynne Byrd, Dr. Gregory Lewbart, and Dr. Donald Neiffer for their assistance with acquiring medical records.

References

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2.  Helmick KE, Bennett A, Ginn P, DiMarco N, Beaver DP, Dennis PM. Intestinal volvulus and stricture associated with a leiomyoma in a green turtle (Chelonia mydas). J Zoo Wildlife Med. 2000;31:221–227.

3.  Jones TC, Hunt RD, King NW. Disturbances of circulation. In: Cann C, ed. Veterinary Pathology. 6th ed. Baltimore, MD: Lippincott Williams & Wilkins; 1997:159–176.

4.  Latimer KS, Rich GA. Colonic adenocarcinoma in a corn snake (Elaphe guttata guttata). J Zoo Wildlife Med. 1998;29:344–346.