Bearded dragon with hepatic disease

17 Bearded dragon with hepatic disease




INITIAL PRESENTATION


Reduced appetite in a bearded dragon.



Introduction


Reptiles often present with vague clinical signs that may have many differential diagnoses, often with multifactorial aetiologies. As ectotherms, their metabolism is slower than mammals and, as such, progression of disease (and resolution of problems) is more prolonged. This case took several months to resolve, requiring great commitment from the owner.



CASE PRESENTING SIGNS


A 1-year-old male bearded dragon (Pogona vitticeps, Box 17.2) presented with a 2 week history of reduced appetite and dysecdysis, and 1 day of dyschezia.



BOX 17.2 Ecology of bearded dragons



• Central bearded dragons originate from Central Australia.

• Their native habitat is semi-arid or arid woodland, and rocky desert.

• They are mostly arboreal, and spend a large amount of time basking on branches or rocks.

• Head bobbing and colour change of the ‘beard’ (throat frill) are used for communication.

• Free-ranging bearded dragons are omnivorous. They mainly eat invertebrates, but may also consume small vertebrates. As they mature, they eat more plant material (e.g. green leaves, fruits, vegetables and flowers).

• Most water intake is via their food.

• Sexual maturity is reached at approximately 18 months of age. The female lays 5–30 eggs per clutch. Males develop prominent pre-femoral pores and bilateral swellings over the hemipenes caudal to the cloaca (Fig. 17.1).

image

Figure 17.1 (a) Cloacal region of a female bearded dragon. (b) Male bearded dragon with prominent pre-femoral pores and hemipenal bulges.



Husbandry


The bearded dragon was housed in a large glass vivarium (1.4 × 0.6 × 0.8 m). The substrate was sand, although linoleum was used in the feeding area to reduce the risk of ingestion of sand and resultant gastrointestinal impaction. Cage furniture included a hide area (synthetic material) and wooden branches for climbing (sited near the basking lamp).


A ceramic bulb, attached to a thermostat, provided supplemental heating. A digital thermometer was used to monitor temperature variations, and showed an ambient temperature in the enclosure of 21°C with a basking temperature under the bulb of 35–41°C. A UV striplight was provided (Box 17.1), positioned approximately 30 cm above the substrate. The light cycle was routinely 12 hours/day.



BOX 17.1 UV lighting for reptiles



• Most reptiles require access to ultraviolet light in the UV-B range, specifically 290–315 nm wavelength, for vitamin D synthesis. (Carnivorous species obtain vitamin D and calcium from the bones in their prey, and some herbivores may also absorb vitamin D from their diet.)

• Artificial UV lights for captive reptiles are usually in the form of a striplight or bulb, some of which also produce heat. These lights produce both visible light and light in the UV range.

• UV production wanes with the age of artificial lights, and it is recommended to replace most every 6–12 months. More accurately, a UV meter can be utilized to gauge UV output and determine when replacement is necessary.

• The lights are usually positioned approximately 12 inches (30 cm) above the reptile. Further away will greatly reduce the quantity of UV reaching the animal’s skin and any closer may result in ocular damage.

The bearded dragon was fed on invertebrates (locusts and silk worms) and fresh vegetables (kale, butternut squash and spring greens). Invertebrates were fed on fruit and vegetables, and dusted with a calcium supplement daily. Vitamin supplements were added to food twice weekly. A shallow water bowl was provided but the animal was not seen drinking from it.



Case History


The owner acquired the bearded dragon from a petshop at approximately 1 month of age. Ecdysis occurred roughly every 10 weeks. Urine/urates/faeces were regularly passed every other day. Endoparasites (oxyurids) had previously been detected and treated (with fenbendazole) in the individual. There had been no recent changes in husbandry.


The current presenting complaints were:


• Reduced appetite for 2 weeks

• Dysecdysis, with intermittent shedding (skin lost piecemeal)

• Straining to pass faeces for 24 hours.


Clinical Examination


Initial examination on presentation revealed:


• Good body condition (weight 540 g)

• Abdominal palpation: no abnormalities palpated, bilateral abdominal fat pads present (normal)

• Oral examination: no abnormalities detected

• No current dysecdysis.


DIFFERENTIAL DIAGNOSES


The differentials for reduced appetite are varied, but may commonly include the following in reptiles:


• Husbandry problems, e.g. inappropriate temperature (too hot or too cool), light or relative humidity

• Gastrointestinal obstruction, endoparasites, or enteritis

• Stomatitis, dental disease (common in captive bearded dragons), or other lesions resulting in oral discomfort

• Offering an inappropriate diet, e.g. herbivorous diet to a carnivore, feeding terrestrial species in a high location

• Hepatic disease, e.g. hepatic lipidosis

• Nutritional disease, e.g. hypocalcaemia, hypovitaminosis A

• Urogenital disease, e.g. renal failure, follicular stasis or egg retention

• Physiologically normal anorexia, e.g. males of certain species in the breeding season, gravid females, hibernation or aestivation, snakes during shedding

• Post-hibernation anorexia (chelonia)

• Respiratory disease, e.g. upper respiratory tract infection, rhinitis/sinusitis, pneumonia

• Metabolic disease

• Intra- or inter-specific aggression

• Viral infections, e.g. herpesvirus (chelonia), paramyxovirus (snakes)

• Sensual deprivation, e.g. blind (e.g. cataracts, corneal lipidosis), loss of smell (e.g. upper respiratory tract [URT] infection)

• Postoperative or post-traumatic ‘stress’

• Psychological, e.g. excess noise, excessive handling (particularly shy specimens), disruptive light patterns, maladaption syndrome in wild-caught individuals, lack of a hide box for visual security

• Terminal neoplasia.


The differentials for dysecdysis are



• Husbandry problems affecting the process of ecdysis
• Excessive environmental temperature

• Low relative humidity

• Lack of rough surfaces to abrade skin

• Poor conditions such as overcrowding may result in immunosuppression, predisposing individuals to infection

• Dehydration

• Ectoparasites, e.g. mites, ticks

• Malnutrition, e.g. hypovitaminosis A (chameleons)

• Dermatitis, bacterial or fungal infection

• Scarring, e.g. from burns or other wounds.


The differentials for dyschezia are



• Constipation (cloacolith or faecolith): owing to reduced gastrointestinal motility in association with hypocalcaemia (husbandry causes), dehydration, or an inappropriate diet

• Enteritis, e.g. endoparasitism, bacterial enteritis

• Poor husbandry, e.g. chronic low environmental temperature

• Gastrointestinal obstruction: foreign body (often substrate ingestion) or gastrolith, intussusception

• Cystic calculi

• Dystocia (females)

• Organomegaly resulting in a space-occupying lesion in the coelomic cavity, e.g. renomegaly with nephritis, abscess(es), neoplasia

• Narrow pelvic canal after trauma or MBD (metabolic bone disease)

• Lethargy.


Case Work-Up



Radiographs


Two projections were taken, a dorso-ventral view using a vertical beam and a lateral view using a horizontal beam (Fig. 17.2). Gas was present within the gastrointestinal tract, but there was no evidence of foreign bodies or other obstruction. There was a suspicion of respiratory disease, with patchy lung fields present (although no respiratory signs had been noted). Increased abdominal volume suggested the presence of faeces, a mass lesion or effusion. A lack of serosal detail precluded a clear picture of the gastrointestinal tract, and may have reflected the presence of fluid or inflammation.


image

Figure 17.2 (a) Lateral and (b) dorso-ventral radiographs of the bearded dragon. In the mid-coelomic cavity, the gas-filled stomach is visible, also seen as a gas-filled dome on the lateral view. The fat bodies appear hazy and further coelomic structures cannot be easily identified. The lung fields appear mildly patchy with uneven borders and the size of the lung fields appears reduced.

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Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Bearded dragon with hepatic disease

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