Effects of allopurinol on plasma uric acid levels in normouricaemic and hyperuricaemic green iguanas (Iguana iguana )

CLINICAL AND PATHOLOGIC FINDINGS IN IGUANIDS WITH SODIUM URATE CHOLELITHIASIS

Four green iguanas (Iguana iguana) and one blue iguana (Cyclura lewisi) from five facilities were diagnosed with sodium urate cholelithiasis. One case was diagnosed antemortem via ultrasonography, and the iguana underwent a choledochotomy for treatment. The other four cases were identified at necropsy. Pathologic hepatic and biliary changes were present in four of the five cases at necropsy. Histologically, four iguanas had hepatic fibrosis, three had bile duct hyperplasia, and one had cholangiohepatitis and pancreaticocholedochitis. Two iguanas had pathologic renal changes. This is the first report of sodium urate cholelithiasis in reptiles. This case series highlights the potential significant clinical disease caused by sodium urate cholelithiasis and the importance of biliary system evaluation. Further investigation is recommended to explore the pathogenesis of reptilian sodium urate cholelith formation.

Investigation of the effects of cricket ingestion on plasma uric acid concentration in inland bearded dragons (Pogona vitticeps)

OBJECTIVE

To determine whether plasma uric acid concentration in inland bearded dragons (Pogona vitticeps) was affected by recent ingestion of a meal of crickets.

ANIMALS

12 healthy adult inland bearded dragons.

PROCEDURES

Food was withheld for 48 hours prior to experiments. Animals (6/group) were randomly assigned to receive a meal of crickets (equivalent to 1% of the animal's body weight; 10 g/kg [4.5 g/lb]; treatment group) or have food withheld for an additional 48 hours (control group). Blood samples were collected for plasma uric acid measurement just before (time 0) and 4, 24, and 48 hours after feeding. Effects of feeding and time on the targeted measurement were assessed by repeated-measures ANOVA.

RESULTS

Mean plasma uric acid concentration for the treatment group was significantly increased from the time 0 value (2.5 ± 1.5 mg/dL) 24 hours following meal ingestion (6.5 ± 1.2 mg/dL), but not at the 4-hour time point, and returned to the time 0 value by the 48-hour time point. No significant changes in plasma uric acid concentration were detected for the control group.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested food should be withheld for ≥ 48 hours prior to blood collection if inland bearded dragons are used to establish reference intervals for plasma uric acid concentration or if feasible when obtaining samples from these animals for clinical evaluation. Veterinarians should consider the time from last meal consumption when interpreting plasma uric acid concentration for this species and potentially other terrestrial insectivorous and omnivorous lizards.

Nephromegaly due to Disruption of Nephrons in the Green Iguana (Iguana iguana)

We describe a fatal kidney disease in green iguanas (Iguana iguana), associated with severe nephromegaly. Affected animals have enlarged kidneys, which fill the pelvic cavity, leading to compression of adjacent organs, obstipation and, ultimately, death. The pathological features of this disease have been poorly described and its aetiology is unknown. We performed detailed gross and histological analyses of 17 green iguanas with a clinical diagnosis of nephromegaly, and compared the results with those of eight healthy controls. Grossly, the kidneys of all 17 individuals were markedly enlarged and the distal colons were distended and overfilled with faecal contents. Histopathological examination revealed that these enlarged kidneys consisted mainly of tubular hyperplasia, resembling poorly developed proximal segments. The nephrogenic zones were either poorly developed or absent. There was a reduction in the density of glomeruli and the distal segments were reduced in number. There was no histological evidence of an aetiology for the nephron disruption and nephromegaly.

Sub-lethal effects induced by a mixture of different pharmaceutical drugs in predicted environmentally relevant concentrations on Lithobates catesbeianus (Shaw, 1802) (Anura, ranidae) tadpoles

The increasing consumption of medications by humans has negative effects such as the increased disposal of these compounds in the environment. Little is known about how the disposal of a "drug mix" (DM) in aquatic ecosystems can affect their biota. Thus, we evaluated whether the exposure of Lithobates casteibeianus tadpoles to a DM composed of different medication classes (antibiotic, anti-inflammatory, antidepressant, anxiolytic, analgesic, and antacid drugs)-at environmentally relevant concentrations-may change their oral morphology, trigger behavioral disorders, and have mutagenic effects on erythrocyte cells. Based on our data, animals exposed to the DM showed changes in mandibular sheath pigmentation, dentition, and swimming activity, as well as atypical behavior in the social aggregation test [with co-specific and interspecific (Physalaemus cuvieri) individuals] and antipredatory defensive response deficit (chemical stimulus from Odonata larvae), after 15 exposure days. The mutagenic analysis revealed higher frequency of nuclear abnormalities in the erythrocytes of tadpoles exposed to the DM (e.g., multilobulated, blebbed, kidney-shaped, notched nucleus, binuclear, and micronucleated erythrocytes). Given the chemical complexity of the DM, we assumed that several organic functions may have been affected, either by the isolated, synergistic, antagonistic, or additive action of DM compounds. Finally, our study confirms the toxicological potential of DM in L. catesbeianus tadpoles, with emphasis to impacts that can affect the fitness of individuals and their natural populations. Thus, we suggest that more attention should be given to the disposal of medications in the environment and reinforce the need of improving water and sewage treatment systems.

Articular gout and suspected pseudogout in a Basilisk lizard (Basilicus plumifrons)

A 9-yr-old male Basilisk lizard (Basilicus plumifrons) with a history of painful and limited mobility for approximately 4 mo, which had seemed to be more pronounced in the front limbs, was presented for necropsy. The animal had exhibited moderate weight loss and anorexia before euthanasia. Postmortem examination revealed yellow-to-white, soft-to-semifirm nodules within the periarticular fascia and musculature of the left and right shoulder joints, hip joints, and stifle joints. Several other joints, including the left and right tarsi, left and right elbow joints, and the left carpus had calcified, white material present on the articular surfaces. Histopathologic evaluation of representative sections of all organs and the joints confirmed tophaceous articular gout and articular pseudogout. The differentiation between articular gout and pseudogout was based on histologic appearance, histochemical staining for calcium, and birefringence under polarized light.