Large meal obstruction in a ball phython (Phyton regius)

Exotics Medicine

Irindi Çitaku,1 DVM, Enrique Yarto,2 DVM, Msc, Cinthia Rodriguez,2 DVM,

1 Albanian Veterinary Association of Exotic and Wild Animals, Tirana, Albania

Centro Veterinario Mexico, Mexico City

 

Abstract

Snakes have a great ability to adapt to a wide range of environmental conditions and due to their fascinating appearance have become common companion pets. Snakes are carnivorous reptiles that show considerable intervals in gastrointestinal transit time and digestion and also display a surprising dilation ability of the esophagus which also is relatively longer than other taxa.1,3

Also, it is known that the stomach of snakes may be small to appropriately accommodate a large prey so the esophagus may storage some of the food items if needed where enzymes may also start the digestion of the prey.In healthy reptiles, the skeletal musculature assists in passage of food.Appropriate digestion of the food through hydrochloric acid prevents putrefaction and can be carried out in the stomach only.4

Lack of owner´s knowledge on digestion time, prey size and prey nutritional-quality may severely affect the snake husbandry and well-being. Precise information to reptile owners as for the frequency of feeding and the appropriate size of the preys is still scarce. It is believed that bigger the prey the better for the animal, but this in fact may result in a number of digestive problems.

Obstruction and gastritis or enteritis due putrefaction of meals in the gastrointestinal tract because of husbandry issues like dehydration or a meal that is too large for the snake is possible and has been documented. 3Lack of owner´s knowledge on digestion time, prey size and prey nutritional-quality may severely affect the snake husbandry and well-being. Ectothermy is strictly linked to husbandry parameters which if disrupted consequently affect digestion and lead to gastrointestinal disturbances in reptiles including maldigestion. Proper husbandry and dietary management of snakes are essential for the well-being of pet snakes.

Clinical case

A 1.8 year-old female ball python (Python regius) presented to the hospital with a history of a two previous feedings on a two-day apart scheme on two hamsters smaller in size than other preys the owner used to supply, lethargy and a distended appearance in the second third of the snake at the level of the stomach (Figure 1). The snake lived in a 60cm large x 40cm wide plastic box. The source of radiation was a ceramic lamp along with a thermal plate below the bottom of the plastic box.

After 5 days of the first feeding the snake showed depressed and had not defecated as it used after each meal approximately five-seven days later which is common after the ingestion of only one prey.A complete physical examination was performed showing a distended celom in the area of the stomach. Palpation of the celomic cavity showed gas along the second and third part of the longitudinal ventral portions of the snake. No other findings were considered of relevance.

Radiographs were taken which revealed the skeletal body of one of the preys surrounded by a considerable amount of gas in the second third of the body. Gas was also present in the last third of the snake compatible with gastritis/enteritis due to bloating and possible intestinal obstruction owing to a foreign body caused by the second prey offered (Figure 2).

The patient was placed in an ICU with a constant ambient temperature of 28°C and 55% humidity. Lactated Ringer´s solution was administered subcutaneously at 15 ml/kg/24h and PO Sucralfate was added to the initial stabilization therapy. Meloxicam was injected i.m. at 0.5 mg/kg after 4 hours of warming and fluid administration.

Fig.1

Figure 1. The distended appearance of the stomach area is seen in this picture previous to the surgical procedure. Head aimed to the upper part of the image.

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Fig.2

Figure 2. Dorsoventral views of the three thirds of the snake showing the stomach occupied by an undigested prey surrounded by gas. The last third shows a considerable amount of gas in the intestinal tract from small to large bowel compatible with bloating.

Exploratory celiotomy was suggested the next day to extract the foreign body (undigested prey) and relieving the gas content. The patient was prepared for surgery after administering antibiotic (Ceftazidime 20 mg/kg i.m) and subcutaneous fluids at the same rate than the previous day.The anesthesia protocol included: midazolam 0.5 mg/kg, alfaxolone 9 mg/kg, and dexmedetomidine 0.075 mg/kg. All drugs were administered i.m. in the epaxial muscles of the second third of the patient. Premedication with midazolam and alfaxolone were administered at the same time. Ten minutes later the snake was sedated so we proceeded to inject dexmedetomidine. A 17G over-the-needle polyurethane catheter was used as endotracheal tube to maintain the anesthesia with isoflurane 0.5 % and 1 L/min of 100% oxygen (Figure 3). Atipamezolat a dose of 0.375 mg/kg was used for the reversal of dexmedetomidine after the surgery which lasted approximately 95 minutes.

The snake was placed over an electric heating pad covered with a towel to protect the skin of the patient while contributing to maintain body temperature. Intermittent positive pressure ventilation at a rate of 2-3 breaths/min were provided all along the anesthesia. Monitoring of the patient all through the procedure was performed with a cloacal probe to asses body temperature. Heart rate was assessed using an ultrasonic doppler and ECG through a SpO2 trends and EtCO2 were monitored and any adjustment needed was carried out.

Fig.3

Figure 3. A 17 G over-the-needle polyurethane catheter was inserted in the trachea as an endotracheal tube to maintain inhaled anesthesia and oxygenation during the entire procedure.

The preparation of the surgical area was performed as routinely with any patient. Celiotomy was performed through a paramedial longitudinal incision at the level of the second third row of scales in the celomic region to approach the stomach for a gastrotomy, just above the area of ​​obstruction, beginning with skin and muscle layers to enter in the celomic cavity and externalize the stomach. Gastrotomy was performed by completely removing the foreign body causing the obstruction. A surgical lavage was performed in the stomach cavity and celomic cavity, with warm Hartmann´s solution.To closure the stomach a continuous suture pattern using non-cutting PDS 4-0 was done, checking the adequate closed organ by means of a leak test. The skin wound closure is best achieved with an inverted suture pattern such as horizontal or vertical mattress, using absorbable sutures inside the cavity and nylon in the outside layer (Figure 4 A-D).

Postsurgical treatment consisted of continued administration of ceftazidime i.m. every 72 hrs, and meloxicam 0.3 mg/kg i.m.every 48 hrs, 5 more applications each.

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Figure 4. Images of the surgical approach for gastrotomy.

A) A paramedial longitudinal incision is done in the second row of scales at the level of the stomach. B) Externalization of the stomach to perform the gastrotomy; C) Extraction of the undigested prey from the stomach; D) Closure of the stomach.

Discussion

Some authors consider the stomachs of healthy reptile predators may accommodate large and intermittent meals since they are distensible.4 However, it has been suggested that juvenile snakes should be fed once every 2-7 days with one prey each time waiting for the animal to defecate before offering the next prey. Adult snakes can be fed every 1-3 weeks.5

Maldigestion has been identified due to meals too large for the snake or preys consumed when carnivorous reptiles do not have access to their preferred optimum temperature zone or those undergoing dehydration.4

 Dehydration in snakes as in other reptiles is linked to inappropriate temperature gradient and low humidity in the enclosure which is particularly important in tropical species.6Putrefaction leading to necrotic gastritis, enteritis and endotoxemia due to gas-producing bacteria are feasible as a cause of maldigestion in snakes.4

Pythons have shown an interesting and selective digestive strategy known as the specific dynamic action or SDA, which allows these snakes to digest the protein components first covering their SDA needs; afterwards digestion of lipids occur more slowly.7

Feeding snakes and other carnivorous reptiles has always been considered straightforward making these reptiles popular and demanded in the reptile trade. Nonetheless, vertebrate animals to feed reptiles and other species must be produced under strict controlled environments to meet the nutritional needs of the predator.

Either fresh and humanely euthanized or frozen/thawed appropriately, rodents of different sizes and life stages should be available for reptile owners to have access to.7 Veterinarians also should identify vendors or sources of rodents to advise their clients on the best source to provide their reptiles a high-quality nutrition.

 

References:

  1. Klaphake E. Reptile gastrointestinal medicine. AAZV Conference, 2015.
  2. Behavioral differences following ingestion of large meals and consequences for management of a harmful invasive snake: A field experiment https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6206181/
  3. De Voe R. Gastroenterology-Oral Cavity, Esophagus, and Stomach. In Divers SJ and Stahl SJ (eds), Mader´s Reptile and Amphibian Medicine and Surgery. 3rd ed, St. Louis, 2019.
  4. Welle KR. Gastrointestinal System. In Current Therapy in Exotic Pet Practice. Mitchell MA and Tully TN (eds), Elsevier, St. Louis, 2016.
  5. Mitchell MA. Snakes. In Manual of Exotic Pet Practice. Mitchell MA and Tully TN (eds), Elsevier, St. Louis, 2009.
  6. Mans C, Braun J. Update on Common Nutritional Disorders of Captive Reptiles. Vet Clin ExotAnim 17 (2014) 369-395.
  7. Boyer TH, Scott PW. Nutrition. In Divers SJ and Stahl SJ (eds), Mader´s Reptile and Amphibian Medicine and Surgery. 3rd ed, St. Louis, 2019.

 

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