Surgery in reptiles: Case studies (Proceedings)
Reptile surgery can be very complicated. Luckily in this day & age of Reptile Medicine, we are afforded several options for anesthetic as well as surgical techniques. This lecture will present a few in order to give an overview of some of the current options available to the practitioner.
Diagnosis and Treatment of Aural Abscesses in Turtles
Here we will discuss the diagnosis, etiologies, and techniques for treating aural abscesses in an Ornate Box Turtle (Terrapene ornata ornata).Signalment
A female, approximately twelve year old, Ornate Box turtle (Terrapene ornata ornata), originally wild caught, kept in captivity for three years.
This turtle presented with slowly progressive swellings on both sides of the turtle's neck, puffiness to both eyes, periodic nasal discharge from both nares, along with decreased appetite and activity.
On presentation, the turtle appeared depressed, weak, and lethargic with significant bilateral aural swellings, mild bilateral blepharoedema, and mild mucopurulent nasal discharge.
Differentials for these clinical signs include the following: bilateral aural abscesses; hypovitaminosis A; upper/lower respiratory tract disease; other infectious; systemic disease; trauma; chemical or parasitic inflammation.
While the exact cause of aural abscesses cannot be definitively stated, most appear to be the result of several predisposing factors. Commonly, affected reptiles are the victims of improper husbandry including chronic suboptimal temperatures and inadequate nutrition. This then results in immunosuppression with development of secondary opportunistic infections. Therefore to arrive at a diagnosis one must begin by taking a thorough history and doing a complete physical examination. Some level of systemic evaluation of the patient is also
indicated, as ancillary diagnostic testing may provide important therapeutic and prognostic data(2,3,20) .
At this time, because of the nature of the reptilian inflammatory response, the location of the inflammatory exudate, and the relative ease of surgical manipulation, a surgical approach appears to be the most appropriate method of treatment(1,11). In the case of chelonians with long standing abscesses and/or those patients with evidence of systemic disease, delaying surgical intervention and instead initiating systemic therapy of antibiotics, fluids, and other appropriately deemed supportive care for three to four days may prove beneficial towards improving the overall outcome of treatment. Delaying surgical intervention while providing needed supportive care tends to decrease the local inflammatory response and may decrease local hemorrhage intraoperatively.
Also, a calculated delay for treatment before surgery may enhance the animal's ability to tolerate the anesthesia through correction of fluid and electrolyteimbalances and may allow time to elevate the patients core body temperature to a point within the preferred optimal temperature zone (POTZ) for that species(8,20).
The author uses the physical and laboratory examination findings to determine the overall health status of the animal. From that point it is determined what degree of supportive care is indicated and when surgical intervention should be planned. Typically most presenting turtles are debilitated and respond to two to three of supportive care prior to the surgery. These turtles are often given warmed intracoelomic fluids, vitamin supplements parenterally as deemed appropriate, and preoperative antibiotics all determined on a case by case basis. They are caged in intensive care where all of their species specific physiologic needs can be met. Surgery is planned when it is determined that the animals are more alert, responsive, and hydrated, and would therefore be better able to tolerate the procedure and anesthesia.
Surgical treatment of aural abscesses should occur using appropriate anesthesia. This allows the surgeon the opportunity to perform thorough debridement of the tympanic cavity and alleviates the pain associated with the treatment of the disease process. Typically the surgical procedure does not take very long, and the author has had good success using Propofol at 10 mg/kg IV (Rapinovet, Pitman-Moore)(4,5). In the author's experience, Propofol provides a quick induction, is short acting, and produces a level plane of anesthesia with a relatively rapid rate of recovery and few side effects. Other anesthetics may also be employed.