Vet Clin Exot Anim 9 (2006) 589–598 Hepatic Lipidosis in a Black-Headed Python (Aspidites melanocephalus) Mark Simpson, BVSc, MACVSc Sugarloaf Animal Hospital, 67 Carrington Street, West Wallsend, NSW, Australia 2286 Hepatic lipidosis (HL) is a common disease condition of captive reptiles. HL is an endpoint for a number of conditions of metabolic derangement that affect the liver. A modification of Thomson’s original definition of HL (as cited by Carlton and McGavin [1]) as ‘‘an excessive, pathological ac- cumulation of lipid in hepatocytes’’ best describes the main features of the condition in reptiles. It is likely that species-specific predisposing factors lead to HL. Many of the predisposing factors leading to these metabolic de- rangements may result directly from aspects of captive husbandry. Some species may be at more risk for this type of hepatopathy than others. Australian pythons of the genus Aspidites (the woma, A ramsayi, and the black-headed python, A melanocephalus) are highly prized captive snakes. In the wild these snakes can be ophiophagous, that is, they eat snakes, as well as lizards and small rodents (Fig. 1). These prey items are generally small and lean, if not emaciated. Black-headed pythons and womas have a low fasting metabolic rate, even in comparison with other pythons [2]. They have evolved to inhabit some of the most unreliable environments in Australia and even in good years may only feed four times. They are active hunters but can, at times when it is metabolically appropriate, spend long periods (even months) im- mobile. In captivity these snakes are generally maintained on diets of rats and rabbits fed weekly to monthly, and they are rarely exercised. These fac- tors are likely to predispose members of this genus in captivity to obesity, and hence to HL, at a greater rate than other reptiles. Case report A 7-year-old, captive-bred female black-headed python was presented for lethargy and anorexia. This snake was part of a large collection owned by an experienced herpetoculturist. It was kept in a wooden box measuring 1800 mm E-mail address: [email protected] 1094-9194/06/$ - see front matter Ó 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.cvex.2006.05.013 vetexotic.theclinics.com 590 SIMPSON Fig. 1. A black-headed python (Aspidites melanocephalus) consuming a juvenile lace monitor (Varanus varius), demonstrating the importance of reptile prey to this species in the wild. (Cour- tesy of John Weigel.) long, 750 mm wide, and 750 mm high. Heat was supplied by a 60-Watt incandescent globe at one end of the enclosure, so that immediately be- neath the globe the temperature was 34C, and at the cool end the thermal gradient dropped to 24C. The snake had been routinely treated annually for ascarids with fenbendazole, and previous routine fecal flotation tests had shown no evidence of parasites. Approximately 7 months before presentation, the snake had been cooled for 8 weeks with a view to stimulating reproductive activity. Cooling was ef- fected by leaving the enclosure light off so that the enclosure was maintained at 24C, which was the background temperature of the snake room. In the pre- vious two breeding seasons, this snake had successfully mated, become gravid, and laid two clutches, each of eight eggs, which had successfully hatched. Although in previous seasons this snake had had an observable ovulation associated with successful reproduction, no evidence of ovulation had been detected in the 5 months since warming. The snake was normally fed a large rat every 10 days. Feeding ceased on cooling, so no prey were offered at this time. The snake failed to resume eat- ing on warming, and, despite attempts to stimulate appetite with novel prey items and altered thermal environment, it remained anorexic. On presenta- tion, therefore, it had not eaten for 7.5 months. No history of other health issues existed. On physical examination, the snake had a snout-vent length (SVL) of 1880 mm, weighed 8.2 kg, and was assessed as being obese. Muscle tone was mildly decreased. Droppings were eliminated during examination and demonstrated significant biliverdinuria, with scant fecal component. Other physical findings were unremarkable. HEPATIC LIPIDOSIS IN A BLACK-HEADED PYTHON 591 Cloacocolonic lavage performed at presentation was unremarkable, with no parasites or their eggs detected. Special attention was given to examina- tion for flagellate protozoa and Entamoeba, but none were found. A hematocrit performed at presentation revealed a packed cell volume of 0.31 L/L and a distinct green discoloration to the serum, indicating a biliverdinemia. A complete blood count demonstrated a normal erythron and unremarkable white cell population. Biochemistry revealed modest elevations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and cholesterol, as well as mild decreases in total protein and glucose. A hepatopathy was considered most likely, and the snake was taken to surgery to obtain a liver biopsy to establish a definitive diagnosis. The snake was premedicated with 3.2 mg butorphanol, injected intramuscu- larly. After 30 minutes, an uncuffed 3-mm endotracheal tube was placed, and anesthesia was induced with manual intermittent positive pressure ventilation (IPPV) every 15 seconds with 4% isoflurane in oxygen. Once the snake was anesthetized, the left jugular vein was cannulated and the cannula connected to a warmed bag of Ringer’s solution delivered by fluid pump at 8 mL/h. Anesthesia was maintained using IPPV every 20 seconds with 2.8% isoflurane in oxygen and was monitored using an ultrasonic Doppler flow detec- tor (Parks Medical Electronics, Aloha, Oregon) to assess cardiac blood flow. Using the tables of McCracken [3], which provide a ratio of the SVL for each organ in the body, the liver was estimated to lie on the right side of the coelom, between 840 mm and 865 mm from the snout. This area was prepared for sterile surgery. A 35-mm paramedian cutaneous incision was made in a scalloped pattern between the first two rows of lateral scales im- mediately dorsal to the ventral scutes, beginning about 850 mm from the snake’s snout. The muscle of the body wall was incised parallel, and approx- imately 3 mm ventral, to the skin incision to avoid the tips of the ribs. The liver was immediately exposed, and three wedge biopsy specimens were col- lected and placed in 10% phosphate-buffered formalin. Hemorrhage was minimal and easily controlled with digital pressure. The muscle layer was closed with single interrupted sutures of 4/0 mono- filament polyglyconate (Maxon, Syneture, Zaltbommel, The Netherlands) and the skin closed to effect eversion using horizontal mattress sutures of the same material. The snake was then ventilated with room air once a min- ute, until spontaneous ventilation began about 12 minutes later. The snake was extubated and placed in a special recovery cage with the temperature maintained at an even 30C across the enclosure. After gradual recovery for 6 hours, surgical fluid therapy was discontinued and the jugular cannula removed. After 36 hours, the snake was transferred to a hospital cage with similar thermal characteristics to the snake’s usual enclosure. A 120-mm deep bed of pelletized, recycled newspaper kitty litter (Breeders’ Choice Cat Litter, FiberCycle, Toowoomba, Australia) with a topping of dried eu- calyptus leaves was provided so that the snake could hide. 592 SIMPSON Histopathologic examination of the liver biopsy specimens revealed marked generalized lipidosis, with moderate portal fibrosis. Occasional mononuclear inflammatory cells were found in the portal areas, as was considerable bile pigment accumulation in macrophages, attesting to the chronic nature of the pathologic condition. Eight days after coeliotomy, enteral nutrition was begun using a carnivore recovery diet (A/D, Hill’s Pet Nutrition, Baulkham Hills, Australia) mixed with an equal volume of 50% dextrose in water (Baxter Healthcare, Toon- gabbie, Australia) to make a slurry and warmed to 30C. Eighty milliliters of this slurry were delivered by soft, red rubber gavage tube (Cook Veteri- nary Products, Toowoomba, Australia) to the midesophagus, approxi- mately 600 mm from the snout. Gentle handling and gravity (encouraging the snake to climb up a branch) were employed to move the slurry to the stomach. This process was then repeated weekly for 5.5 months. Crushed and mixed with the slurry at the first instance, and once each month thereafter, were 2 g of carnitine and 500 mg of methionine. At the time of the initial tube feeding, 100 mg of vitamin C and 0.3 mL of vitamin B complex were administered intramuscularly. Each week, on the day before gavage feeding, the snake was taken onto the lawn and encouraged to wander in the sunshine for 30 minutes. The snake would consistently head toward a low, dark garden border, which it presumably felt would provide cover. By gently and repeatedly picking the snake up and placing it in the center of the lawn, one could make it move actively for the entire 30 minutes. The snake completed ecdysis twice during recovery, at 4 and 7 months after surgery. The shed skin had to be moistened and removed manually from the surgical site the first time, but subsequent shedding was uneventful. Twenty-three weeks after the biopsy and 10 days after the last gavage feed, a killed mouse was offered as prey and was eagerly consumed. It had been 12 months since the snake’s last voluntary meal. The snake’s weight at this time was 7 kg. A recommendation was made to the owner at this stage for a repeat of the liver biopsy, but it was declined. The snake was fed a pre-killed adult mouse every 21 days for the next 12 months.