Cholelithiasis in adult bearded dragons: retrospective study of nine adult bearded dragons (Pogona vitticeps) with cholelithiasis between 2013 and 2015 in southern Germany

Abstract

SummaryWith an increased number of pet reptiles, many diseases occur due to nutritional disorders. Between 2013 and 2015, irregular gallbladder contents (sludge/choleliths) in adult bearded dragons (Pogona vitticeps) were recorded in many of the routinely conducted necropsies at the reptile rescue station in Munich (Auffangstation f€ ur Reptilien, M€ unchen e.V., Munich, Germany). Nine animals, six from the rescue station and three from an associated veterinary practice (Tier€ arztliche Praxis f€ ur Exoten, Augsburg, Germany), were studied. Gallbladder contents from all animals were analysed at the Institute for Clinical Chemistry in Zurich, Switzerland. In three of nine animals, one cholelith composed of 100% calcium carbonate (CaCO 3 ) was detected and it precipitated either as pure calcite or as a calcite:vaterite combination. In the remaining six animals, analyses suggested a protein-based material. The detection of choleliths/sludge was not anticipated at necropsy or surgery in eight of nine animals. The diet of the six animals from the rescue station was retrospectively described as mainly insects, whereas the diet of the three animals from the veterinary practice also contained little plant matter. Fed insect species were mealworm larva (Tenebrio molitor), house cricket (Acheta domestica), migratory locust (Locusta migratoria) and zophobas larva (Zophobas morio), all high in protein and fat. In other species, a nidus must be present for CaCO 3 to precipitate. As a protein-based sludge was detected in six gallbladders, it is possible that a high-protein diet could lead to such a nidus and subsequently to cholelith formation. Cholelithiasis seems to be a rising problem in adult bearded dragons and is likely underdiagnosed, as many choleliths were found at necropsy. This rise in cholelithiasis may correlate with an unnatural high-protein, high-fat insect-based diet instead of a balanced plant-based diet.

Diagnosis and Surgical Management of Cholecystolithiasis in Two Adult Inland Bearded Dragons (Pogona vitticeps)

“…The true prevalence of choleliths in bearded dragons is currently unknown. This condition has been reported in seven adult bearded dragons (one individual in Ritzman and Garner [2009]; six of nine individuals in Gimmel et al [2017]), in addition to the two cases presented herein.…”

“…Postmortem evaluation was necessary to identify irregular gallbladder contents such as sludge and choleliths in eight of nine adult bearded dragons in a previous study, whereas the antemortem sonographic evaluation revealed a gallbladder cholelith in only one individual (Gimmel et al, 2017). Cholecystolith was present in 6 of 9 cases, sludge in 3 of 9 cases, and both cholecystolith and sludge in 1 of 9 cases.…”

“…The remainder of the physical examination was unremarkable. Differential diagnoses included digestive impaction (Mans, 2013); neoplasia, such as neuroendocrine gastric carcinoma/ somatostatinoma (Ritter et al, 2009) and gallbladder (Jakab et al, 2011) or hepatic (Griswold, 2001) neoplasms; and cholelithiasis (Gimmel et al, 2017). Dorsoventral and lateral whole-body radiography was unremarkable.…”

“…1). The ultrasonographic appearance of the markedly distended gallbladder was highly suggestive of cholecystolithiasis (Wachsmann, 2010;Bucy et al, 2015;Gimmel et al, 2017). Although cholecystostomy was considered, risk of recurrence and function of the gallbladder was questionable given the severe distension of the organ.…”

“…Information on the diagnosis and treatment of cholelithiasis, and in particular cholecystolithiasis, in lizards is scarce. Surgical removal of choleliths has been reported in three adult bearded dragons who subsequently successfully recovered (Ritzman and Garner, 2009;Gimmel et al, 2017). However, in these cases, the surgical procedure was not thoroughly described.…”