Ultrasonographic anatomy of reproductive female leopard geckos (Eublepharis macularius)

Metastasizing dysgerminoma in an inland bearded dragon (Pogona vitticeps)

BACKGROUND

Malignant dysgerminomas are infrequently reported ovarian neoplasms in animals, especially in exotic pets (non-traditional companion animals [NTCAs]). In the few published case reports on reptilian species, examples are primarily postmortem without antemortem (clinical) assessment.

PATIENT PRESENTATION

An adult, 13-year-old, spayed female inland bearded dragon (Pogona vitticeps) presented with lethargy, a right-sided head tilt, unilateral exophthalmos and ventrotemporal strabismus on the right eye. On examination, a palpable mass (approximately 3.5 cm in diameter) was detected within the mid coelomic cavity. Computed tomography revealed a retrobulbar swelling and lytic bone lesions affecting the right frontal bone and several vertebrae (T11, T13, and T14). Multiple nodules of soft tissue opacity were also detected within the lungs, liver, and coelomic fat bodies. Haematology revealed leukocytosis with heterophilia and toxic granulation of heterophils. On the basis of these results, differential diagnoses included disseminated abscesses, granulomas (e.g., due to mycobacteriosis) and neoplasms. The lizard was subsequently euthanized due to end-stage disease and a poor prognosis. Postmortem gross examination and histopathology revealed a primary ovarian dysgerminoma with evidence of widespread metastasis as well as localized tissue destruction affecting the right retrobulbar space and frontal bone, the spinal column, the lungs, the liver, and both coelomic fat bodies.

CONCLUSIONS

This report describes a case of malignant dysgerminoma with widespread intraosseous and visceral metastases in a captive inland bearded dragon (Pogona vitticeps).

Folliculectomy for the treatment of pre-ovulatory follicular stasis in three illegally captured West Coast green geckos (Naultinus tuberculatus) to enable wild rehabilitation

CASE HISTORY

In 2023, the New Zealand Department of Conservation seized 63 endemic reptiles that were being held without a permit. This group included three adult female West Coast green geckos (Naultinus tuberculatus) that had been illegally removed from the wild 2 years earlier. They had been held in an outdoor enclosure with a pair of goldstripe geckos (Woodworthia chrysosiretica).

CLINICAL FINDINGS

On physical examination, all three geckos had at least two soft palpable masses in the coelom. Repeated ultrasonographic examination over several months confirmed the diagnosis of pre-ovulatory follicular stasis (POFS) in each gecko, and in subsequent weeks, more ovarian follicles developed in each animal.

LABORATORY FINDINGS

All three geckos were negative on culture of cloacal swabs for Salmonella spp., and negative on PCR assay of a cloacal flush for Cryptosporidium spp., despite other reptiles in the seized group showing positive results for multiple Salmonella spp., and one other gecko being positive for Cryptosporidium parvum, subtype IIcA5G3.

TREATMENT AND OUTCOME

For all three geckos, para-midline ventral coeliotomy was performed under general anaesthesia, and folliculectomy of degenerate ovarian follicles was performed. Post-operative complications were seen in all three animals, which developed suture-line infections following disruption of normal skin shedding and entrapment of shed keratin in the surgical sites. A second surgery was undertaken to remove impacted keratin and caseous inflammatory material from the surgical wounds of all three animals and buried sutures were placed to close the coelomic wounds. The geckos were treated with 20 mg/kg ceftazidime IM every second day for 2 weeks post-operatively. Subsequent ecdysis (skin shedding) occurred without complication and the geckos were released back to the wild 10 months after admission.

CLINICAL RELEVANCE

The recommended treatment for POFS in reptiles is ovariectomy, which is not appropriate for wild animals. The use of folliculectomy to resolve preovulatory follicular stasis should be considered for animals where retaining reproductive ability is essential.

UNILATERAL OVARIAN TORSION IN FIVE GECKOS: CLINICAL AND ULTRASOUND FINDINGS

Few cases of antemortem ovarian torsion and diagnosis have been described in reptiles. This case series reports clinical and ultrasound findings in five adult (aged 1-6 yr) female geckos (three leopard geckos [Eublepharis macularius], one crested gecko [Correlophus ciliatus], and one gargoyle gecko [Rhacodactylus auriculatus]) diagnosed with unilateral ovarian torsion between 2019 and 2023. All animals presented with acute weakness associated with coelomic distension, and one suffered from chronic diarrhea and cachexia. Coelomic ultrasound examination (12-MHz linear probe) revealed signs of bilateral follicular stasis and oophoritis in all cases (heterogenic follicles ≤1.3 cm diameter) associated with a large anechoic periovarian rim and a hyperechoic chord, consistent with twisted ovarian vessels. Blood supply to ovarian structures was not detected using a Doppler flow, and a unilateral ovarian torsion was diagnosed in all geckos. A bilateral ovariectomy was performed under general anesthesia in all five animals. The mass of the excised ovaries varied between 7 to 15 g (12.7-22.2% of body weight). One gecko died 1 d postsurgery; the four remaining animals were healthy 6 mon postsurgery. Gekkonids are unique among reptiles in that they undergo a monoautochronic ovulation (only one follicle is recruited by each ovary during each ovarian cycle); the presence of multiple vitellogenic follicles on each ovary facilitates the diagnosis of follicular stasis. This condition was present in all five geckos and was suspected to have led to ovarian torsion. This case series emphasizes the value of ultrasound examination for antemortem diagnosis of reproductive disorders in reptiles.

GROSS AND ULTRASONOGRAPHIC ANATOMY OF THE COELOMIC ORGANS OF HEALTHY AXOLOTLS (AMBYSTOMA MEXICANUM)

The objectives of this study were to describe the gross anatomy and ultrasonographic appearance of coelomic organs in subadult and adult axolotls (Ambystoma mexicanum), to describe an ultrasound technique, and to test correlations of ultrasonographic measurement with body length, width, and weight. Necropsies of coelomic organs were conducted on 10 axolotls (females = 5; males = 5) and ultrasound on 11 (males = 5; females = 6). Animals were kept in water and maintained conscious during ultrasound. The heart, caudal vena cava, liver, gallbladder, spleen, esophagus, stomach, colon, kidneys, ovaries, and fat bodies were identified in all study subjects, although testicles were identified in only 6/7 subjects. The pancreas and adrenal glands could not be identified in any animals, either during necropsy or ultrasonography. Coelomic and pericardial effusion was present in all animals. Ultrasonographic measurements of the liver, spleen, myocardial thickness, and right and left kidney length were highly repeatable (correlation value [CV] < 5%) and the esophagus, spleen, caudal vena cava, fat bodies, gallbladder, colon thickness, right kidney height and width, and right testicle diameter were statistically repeatable (CV < 10%).

Sex Determination in Two Species of Anuran Amphibians by Magnetic Resonance Imaging and Ultrasound Techniques

The objective of the present study was to evaluate whether gender determination in two amphibian species (Kaloula pulchra and Xenopus laevis) can be reliably carried out by means of magnetic resonance imaging (benchtop magnetic resonance imaging; BT-MRI) or ultrasound (high-resolution ultrasound; HR-US) techniques. Two species of healthy, sexually mature anurans have been used in the present study. Eight Kaloula (blind study) and six Xenopus were used as controls. Magnetic resonance imaging experiments were carried out on a low-field (1 Tesla) benchtop-MRI (BT-MRI) system. HR-US examination was performed with high-resolution equipment. Low-field BT-MRI images provided a clear and quantifiable identification of all the sexual organs present in both genders and species. The HR-US also allowed the identification of testes and ovaries in both species. Results indicate that BT-MRI allowed a very precise sex identification in both anuran species, although its use is limited by the cost of the equipment and the need for anesthesia. HR-US allowed an accurate identification of ovaries of both species whereas a precise identification of testes is limited by the ultrasonographer experience. The main advantages of this technique are the possibility of performing it without anesthesia and the higher availability of equipment in veterinary and zoo institutions.

Inside the shell: body composition of free-ranging tortoises (Testudo hermanni)

Body condition indices (BCI - mass scaled by size) are widely used in ecological studies. They presumably reflect variations of endogenous fat reserves in free-ranging animals. In the field, however, accurately quantifying internal body reserves is a difficult task. This is especially true in armoured animals where convenient clues that may guide BCI assessment (e.g. visible subcutaneous fat deposits) remain inaccessible. Alternatively, inclusive dissections may provide anatomical abacuses to estimate body reserves in living individuals. Sacrificing animals for this purpose is not acceptable. We opportunistically tested the ability of BCI to estimate body reserves in 13 free-ranging Hermann's tortoises (Gmelin, 1789) dissected soon after they died from natural causes. On average, BCI values were lower in dissected tortoises relative to living individuals (N > 10,000 measurements), but they remained within the range of variation of the studied populations. Shell mass relative to body mass was high and showed considerable inter-individual variation (33.5% to 52.3%). Stomach and digestive tract content represented another important and variable part of total body mass (4.4% to 14.5%). The contribution of fat bodies was negligible (0.0% to 0.5%). Overall, in the studied tortoises, variations of body condition are weakly determined by variations of fat stores. Other endogenous (e.g. muscles, visceral tissues, liver) and "exogenous" (e.g. digestive tract content, clutch) elements should be considered to better understand age and sex specific life-history trade-offs faced by chelonians.

Diagnostic Imaging of the Reptile Urinary System

Reptiles can develop various diseases of the urinary tract, including, but not exclusively, urolithiasis, gout, acute and chronic kidney injury, and secondary renal hyperparathyroidism. Diagnostic imaging is instrumental in differentiating and diagnosing these ailments. This article describes the current diagnostic imaging approaches used in reptile medicine for evaluation of urinary tract disease. The use of radiographs, ultrasonography, computed tomography, MRI, and endoscopy is discussed and compared for the evaluation of urinary tract disease in reptiles.

Ultrasonographic appearance of the coelomic cavity organs in healthy veiled chameleons (Chamaeleo calyptratus) and panther chameleons (Furcifer pardalis)

Veiled chameleons (Chamaeleo calyptratus) and panther chameleons (Furcifer pardalis) are the most popular chameleons over the world, and consequently, two of the most frequent species presenting to veterinary practices. However, published studies on normal ultrasonographic anatomy for these lizards are currently lacking. The objectives of this prospective anatomic study were to develop an ultrasound protocol for evaluation of the coelomic cavity in these species and describe the normal ultrasonographic anatomy of the coelomic organs. Seventeen healthy veiled chameleons and 15 healthy panther chameleons were included. A linear 18 MHz transducer was used. Chameleons were sedated and restrained in right lateral recumbency by an assistant. Longitudinal and transverse images were acquired, and authors recorded qualitative and quantitative ultrasonographic characteristics of the coelomic structures. The kidneys, liver, caudal vena cava, hepatic veins, portal vein, gallbladder, wall of the stomach and intestine, gonads and, when distended, urinary bladder could be visualized during ultrasonography of the coelomic cavity in both species. The spleen, pancreas, and adrenal glands could not be identified. Findings from the current study supported the use of ultrasonography for veiled chameleons (Chamaeleo calyptratus) and panther chameleons (Furcifer pardalis) with suspected intracoelomic diseases and provided normal reference information for future studies of these chameleon species.

Specific anatomy and radiographic illustration of the digestive tract and transit time of two orally administered contrast media in Inland bearded dragons (Pogona vitticeps)

The aim of this study was to describe the specific gross and radiographic anatomy of the digestive tract of inland bearded dragons (Pogona vitticeps). Eleven bearded dragon cadavers of both sexes (6 females, 5 males) were dissected to examine, measure, and document the specific gross anatomy of the alimentary canal. Measurements collected from the cadavers included snout-vent length, total length of the alimentary canal, and the lengths of the individual sections of the gastrointestinal tract, including the esophagus, stomach, small intestine, ampulla coli, isthmus coli, rectum, and the distance from the coprodeum to the vent opening. Twenty-two healthy adult bearded dragons (13 females, 9 males) maintained under standardized husbandry conditions underwent a physical examination, blood collection, and whole-body dorsoventral and lateral survey radiographs; these animals were used to provide the radiographic images of the complete digestive tract. For the subsequent contrast passage studies, two different contrast media, barium sulfate (BaSO₄, Barilux suspension) and an iodinated ionic radiocontrast agent (Sodium meglumine amidotrizoate [SMAT], Gastrografin), were used. Water-diluted Barilux suspension (dose 9 ml/kg) was administered orally to 5 bearded dragons, while Gastrografin (dose 5ml/kg) was administered orally to 21 bearded dragons. Four animals were used for both contrast media studies, but received a break of four weeks in between. Dorsoventral and laterolateral radiographs were collected at 0 (baseline), 15, 30, and 45 minutes and 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 30, and 36 hours after each contrast medium was administered. Both contrast media were found to illustrate the alimentary tracts in the adult bearded dragons. Transit time was substantially faster with SMAT, and SMAT illustrated the entire gastrointestinal tract within 36 hours; BaSO₄ did not fully illustrate the gastrointestinal tract in 36 hours. These results might serve as a guideline for the interpretation of subsequent contrast studies in this lizard species.