Exotic mammal renal disease: diagnosis and treatment

Disease Overview of the Urinary Tract in Exotic Companion Mammals and Tips on Clinical Management

Diseases of the urinary tract are reviewed, covering infectious (bacterial, viral, parasitic), degenerative, congenital, metabolic, nutritional, neoplastic, obstructive, and toxic causes. Some clinical presentations and diagnostic procedures are described for ferrets, rabbits, guinea pigs, hamsters, mice, rats, chinchillas, hedgehogs, and sugar gliders, as well as therapies.

BILATERAL HYDRONEPHROSIS IN A SUGAR GLIDER (PETAURUS BREVICEPS)

An adult, intact male sugar glider ( Petaurus breviceps ) presented for acute caudal abdominal swelling. Treatment by the referring veterinarian included aspiration of urine from the swelling. On physical examination, mild depression, pale mucus membranes, and caudal abdominal swelling were noted. Focused ultrasonographic assessment revealed a fluid-filled caudal abdominal structure and subjective bladder wall thickening. The following day, the sugar glider was severely depressed. Hematology results included hypoglycemia, hyperkalemia, hyponatremia, and azotemia. Ultrasonography revealed bilateral hydronephrosis and hydroureter. Despite supportive care, the animal died. Postmortem examination confirmed bilateral ureteral dilation, renal petechial hemorrhage, and dilation of the right renal pelvis. Submucosal edema, hemorrhage, and lymphoplasmacytic infiltration of the urinary bladder, ureters, and renal pelvises were noted. Hyperplasia of the urinary bladder and ureteral epithelium, coupled with inflammation, may have caused functional obstruction leading to bilateral hydronephrosis and hydroureter. This is the first reported case of hydronephrosis in a marsupial.

A randomized controlled trial of factors influencing fire occurrence during laser surgery of cadaveric rodents under simulated mask anesthesia

OBJECTIVE

To determine whether face mask fit during anesthesia affects the occurrence of fire episodes during laser surgery in nonintubated cadaveric rodents under volatile anesthesia.

DESIGN

Adaptive single-center randomized controlled trial with an interim analysis.

SAMPLE

100 dead rats intended for animal consumption.

PROCEDURES

Rat carcasses were randomly allocated to undergo simulated anesthetic procedures with 2 face masks: open mask versus tight-fitting mask. Under volatile anesthesia, 4 cutaneous surgeries were performed (skin biopsies at 3 different sites and resection of a pinna) by means of a diode laser on each carcass. A single interim analysis of 50 rats was planned a priori to drop an arm of the study in the case of a highly significant difference in the incidence of fire events. Surgeries would have continued with the other face mask until completion of the study. Univariate and multivariate analyses were performed.

RESULTS

Overall, 25 surgeries were performed with open face masks and 75 with tight-fitting masks. During 400 surgical procedures on 100 rat carcasses, 11 (11%; 95% confidence interval, 5.62% to 18.83%) fire events occurred. Ten fire events occurred with the open masks, and 1 fire event occurred with the tight-fitting masks (relative risk, 30.0; 95% confidence interval, 4.0 to 222.8). All of the fire events occurred on different carcasses when cheek skin biopsy was performed. Procedure time, body weight, and surgeon did not significantly concur in the prediction of fire events.

CONCLUSIONS AND CLINICAL RELEVANCE

Modification of open masks by the addition of a latex diaphragm significantly reduced the occurrence of fire ignition during laser surgery. Results suggested that open masks should not be used for laser surgery of nonintubated rodents during volatile anesthesia. Additionally, results indicated that surgical lasers should be avoided for facial surgery of nonintubated anesthetized rodents, even if tight-fitting masks are used.

Lateral approach to nephrotomy in the management of unilateral renal calculi in a rabbit (Oryctolagus cuniculus)

CASE DESCRIPTION

A 5-year-old 2.23-kg (4.91-lb) spayed female Lop rabbit (Oryctolagus cuniculus) was evaluated because of a history of lethargy, polyuria, and polydipsia of 1 month's duration. The referring veterinarian made a presumptive diagnosis of hypercalcemia of unknown etiology on the basis of a plasma total calcium concentration of 14.0 mg/dL.

CLINICAL FINDINGS

Physical examination findings were unremarkable. Hematologic and plasma biochemical analysis revealed nonregenerative, normocytic, normochromic anemia (PCV, 28%) with heteropenia (23%; 1,334 heterophils/mL) and a total plasma calcium concentration of 16 mg/dL. Radiographic and ultrasonographic examination revealed radiodense and hyperechoic structures in both renal pelves and right unilateral nephrolithiasis.

TREATMENT AND OUTCOME

Nephrotomy was performed via laparotomy with a right lateral approach. A nephrolith composed of calcium carbonate and carbonate apatite was removed from the right renal pelvis. The rabbit's plasma tested positive for antibodies against Encephalitozoon cuniculi by means of an indirect immunofluorescence assay, and fenbendazole (20 mg/kg [9.1 mg/lb], p.o., q 24 h) was administered for 28 days. Although plasma calcium concentration was not substantially decreased after treatment (values were 14.1 and 15.1 mg/dL 1 week and 3 months after surgery, respectively), the patient did not have clinical signs of hypercalcemia and died of unrelated causes approximately 1 year after surgery.

CLINICAL RELEVANCE

To the authors' knowledge, this is the first report of a nephrotomy performed in a rabbit via a lateral abdominal approach. This approach allowed easy location of the kidney and also reduced manipulation, thus decreasing the risk of damaging the abdominal viscera and potentially decreasing postoperative pain.

Urine specific gravity values in clinically healthy young pet ferrets (Mustela furo)

OBJECTIVES

To determine urine specific gravity values in clinically healthy pet ferrets and explore possible associations with sex, sampling techniques, hydration status and urine analytes.

METHODS

Sixty-nine entire ferrets of both sexes, under one year of age, were included in this study. Physical examination, complete blood count, blood biochemistry, urine microscopy, urine dipstick and urine specific gravity were performed on all ferrets. Urine specific gravity was determined using a handheld urine refractometer. Statistical analysis was performed to determine urine specific gravity value intervals and to test for associations with sex, sample collection method, packed cell volume, plasma total protein concentrations and urine analytes.

RESULTS

Urine specific gravity differed by sex in ferrets as females exhibited a lower urine specific gravity (P<0·001). There was no significant correlation between urine specific gravity, sampling method, packed cell volume/total protein and urine dipstick analytes. Mean urine specific gravity reported in this study was 1·051 for entire males (sd ±9; range 1·034 to 1·070) and 1·042 for entire females (sd ±8; range 1·026 to 1·060).

CLINICAL SIGNIFICANCE

Results of this study may allow clinicians to have a more accurate evaluation of the ability of those animals to concentrate urine by comparing their urine specific gravity results to those obtained from this cohort of clinically healthy animals.

Advanced diagnostic approaches and current management of internal disorders of select species (rodents, sugar gliders, hedgehogs)

African pygmy and European hedgehogs, sugar gliders, and rodents such as rats, mice, gerbils, hamsters, guinea pigs, and chinchillas are becoming increasingly popular as pets in the United States, and more practitioners are being asked to examine, diagnose, and treat these animals for a bevy of disorders and diseases. Many procedures and techniques used in traditional small and large animal medicine are used for these species, with minor adaptations or considerations. This article examines available diagnostic tools and treatment methodologies for use in hedgehogs, sugar gliders, and selected rodents.

Unilateral nephrectomy for hydronephrosis in a pet rabbit

A young rabbit was diagnosed with unilateral hydronephrosis. The affected kidney was surgically removed. Nearly 3 years after the nephrectomy, the rabbit is doing well. The diagnosis, surgery, and pathophysiology of unilateral renal obstruction are discussed in this article.