Quantitative Analysis of 4468 Uroliths Retrieved from Farm Animals, Exotic Species, and Wildlife Submitted to the Minnesota Urolith Center: 1981 to 2007

Chronic Kidney Disease and Kidney Stone in a Wild Chimpanzee (Pan troglodytes verus) in Côte d'Ivoire

An older wild female chimpanzee (Pan troglodytes) was found dead with a large calcium oxalate stone in the renal pelvis. Histopathological changes included glomerulosclerosis, interstitial nephritis and fibrosis, focal mineralization, and medial hypertrophy. Urinary albumin-creatinine-ratio showed increased values from 15 months before death. Causes of the kidney disease remain unconfirmed.

Lower Urinary Tract Diseases in Guinea Pigs: A 14-Year Retrospective Study (2004-2018)

The clinical records of all guinea pigs diagnosed with a lower urinary tract disease in a single veterinary hospital, over a period of 14 years (2004−2018), were retrospectively searched in order to characterize this population and investigate the potential association between the epidemiological and clinical variables. A total of 117 clinical cases were identified, corresponding to 57 animals. Urolithiasis was the most common diagnosis (n = 52; 44.4%), followed by cystitis and/or a urinary tract infection (UTI). Several statistically significant associations (p < 0.05) were found between different variables, showing that female guinea pigs were more likely than the male ones to have a previous family history of urinary disease, to present dysuria and stranguria at admission, and to suffer recurrence. Moreover, males were more prone to urolithiasis and females to cystitis/UTI, and animals diagnosed with cystitis/UTI frequently had more clinical urinary signs and abdominal pain on palpation compared to those diagnosed with urolithiasis. Finally, the use of potassium citrate and the urethrotomy approach were associated with a better therapeutic response. Further studies are needed in larger populations of guinea pigs to confirm the present findings, especially as some of them were described for the first time.

Urolithiasis in a captive Siberian chipmunk (Eutamias sibiricus)

This clinical case describes struvite urolithiasis in a pet chipmunk. Physical examination revealed the presence of two ovoid palpable masses in the caudal part of the abdomen, which were later confirmed by radiography as urinary bladder stone. The animal underwent ventral midline laparotomy and uroliths were successfully removed. Uroliths analysis revealed the presence of struvite and bacteriology showed the presence of Proteus mirabilis. Little is known about aetiology and incidence of urolithiasis in chipmunks. Client education about husbandry, dietary needs, and animal behaviour is necessary, especially when dealing with less commonly kept exotic companion mammals. This is the first report of struvite urolithiasis in a pet chipmunk.

RADIOLOGIC MEASUREMENT AND DETERMINATION OF KIDNEY-TO-VERTEBRA RATIOS AS A METHOD OF ESTIMATING RENAL SIZE IN SERVALS (LEPTAILURUS SERVAL)

Numerous conditions, from acute to chronic renal changes, have the potential to alter the renal size on radiographs. However, current literature does not provide any radiographic reference range for the normal renal size in the serval (Leptailurus serval). This retrospective study includes 13 healthy adult servals, seen between 2004 and 2017 at the UTCVM Veterinary Medical Center, deemed healthy based on physical examination and blood work. Orthogonal radiographs were anonymized, calibrated, and evaluated blindly by three observers of different experience levels. Renal and individual lumbar vertebral body lengths were measured on both orthogonal views, and ratios of kidney length to each lumbar vertebral length were calculated on both views. On the ventro-dorsal projection, the kidney length to L5 vertebra ratio had the lowest standard deviation (SD) with a mean of 1.82, SD of 0.27, and 95% confidence interval (CI) (1.63-2.00). On the lateral view, the kidney length to L3 vertebra ratio had the lowest SD with a mean of 2.03, SD of 0.25, and 95% CI(1.86-2.20). Statistically, all three observers were shown to be in agreement, indicating reproducibility of the measurements among observers with different levels of expertise.

The effect of antimicrobial treatment on mortality associated with urinary tract disease in mink kits (Neovison vison)

Mink urinary tract disease (MUTD) often presents as urolithiasis and/or cystitis and is known as an important cause of mortality in mink kits during the early growth season. Antimicrobial flock treatment has been routinely applied as preventive/therapeutic protocol on Danish mink farms with increased mortality associated with MUTD. The therapeutic effect of this treatment strategy has not previously been investigated. In this study, we applied controlled parallel group treatment trials to assess the effect of sulfadiazine/trimethoprim and amoxicillin treatment on mortality associated with MUTD in mink kits. On farm A, eight mink kits were diagnosed with MUTD post mortem in the treatment group (n = 1920, sulfadiazine/trimethoprim treatment: 30 mg/kg, q 24 h, P.O for 5 days) compared to 16 in the untreated control group (n = 1920). No significant difference in mortality associated with MUTD were found between  the treatment and the control group using the Fisher’s exact test (P = 0.15). Treatment group 2 (n = 1920, amoxicillin treatment: 14 mg/kg q 24 h, P.O for 5 days) and treatment group 3 (n = 2088, amoxicillin treatment: 7.5 mg/kg q 24 h, P.O for 5 days) were investigated on farm B. Eight and four mink kits were diagnosed with MUTD post mortem in group 2 and 3, respectively. No difference between occurrence of MUTD were found between the control group and treatment group 2 (P = 0.42) or treatment group 3 (P = 0.75). No significant difference between final body weights or weight gain were found between treatment and control weighing groups on farm A or B. In conclusion, antimicrobial treatment administered in the feed showed no significant effect on weight gain or mortality associated with MUTD on the farms included in this study.

Ultrasound-guided percutaneous antegrade pyelography for suspected ureteral obstruction in 6 pet guinea pigs (Cavia porcellus)

Objectives

To describe the feasibility and safety of ultrasound-guided percutaneous antegrade pyelography (US-PAP) in pet guinea pigs (Cavia porcellus) with suspected ureteral obstruction.

Materials and methods

Six adult pet guinea pigs (4 females and 2 males, all intact) were evaluated for suspected ureteral obstruction. The mean weight of the guinea pigs was 0.8 ± 0.25 kg (range 0.4–1.1 kg), and mean age was 4.07 ± 1.63 years (range 2–7 years). All animals were free from comorbid diseases, had clinical signs of urologic disease and were referred based on either strong clinical suspicion of, or diagnostic imaging of ureteral obstruction. Data on signalment and clinical examination findings, response to anaesthesia and imaging findings were recorded.

Results

Partial ureteral obstruction was confirmed in all guinea pigs but one, in which a complete ureteral obstruction occurred. Uroliths were in both ureters of 5 cases and in both the left renal pelvis and ureters in 1 case. All guinea pigs showed a normal appetite and regular defaecation within 2 h following the procedure. No intraoperative or immediate postoperative complications were encountered after the procedure. The only complication was contrast medium leakages in the subcapsular perinephric, retroperitoneal and, in one case, peritoneal space, which caused no overt clinical consequences afterwards. In one male patient, mobilisation of the ureteral calculus occurred and the urolith was found in the urinary bladder on the radiograph taken after contrast medium injection.

Clinical significance

The US-PAP technique is a useful, safe and easy-to-perform diagnostic tool in guinea pigs with hydronephrosis and hydroureter.

Associations between biochemical parameters and referral centre in pet rabbits with urolithiasis

OBJECTIVES

To determine the association between signalment, selected haematologic and biochemical parameters and referral centre in pet rabbits with imaging evidence of urolithiasis presented to two veterinary teaching hospitals in North America.

MATERIALS AND METHODS

The medical record database of two veterinary teaching hospitals was searched from 2009 to 2019 for records of pet rabbits that received both imaging studies and plasma biochemistry profiles. Information regarding signalment, bodyweight, packed cell volume, total solids, and plasma biochemistry profiles was obtained. Univariable and multivariable logistic regression models were performed to identify statistically significant parameters associated with imaging evidence of urolithiasis.

RESULTS

Of the 324 examined rabbits, 33 (10.2%) had confirmed evidence of urolithiasis on imaging. Increasing plasma calcium and sodium concentrations and referral centre were significantly associated with the presence of urolithiasis on the univariable logistic regression model. However, only plasma calcium concentration and the referral centre demonstrated significant associations on the multivariable logistic regression model.

CLINICAL SIGNIFICANCE

Results indicate that urolithiasis in pet rabbits that receive imaging is associated with mildly increasing plasma calcium concentration and referral centre. The association with referral centre may indicate there are geographic influences on urolithiasis or on imaging. However, the identified associations have low predictive value for the diagnosis of urolithiasis, indicating the need for additional diagnostic modalities.

Survey of tortoises with urolithiasis in Japan

Urolithiasis is a disease often seen in tortoises at veterinary hospitals, however there have been no comprehensive research reports of tortoises with urolithiasis in Japan. In this study, we analyzed tortoises diagnosed with urolithiasis at three domestic veterinary hospitals. Based on medical records, we assessed the diagnostic method, species, sex, body weight, dietary history, husbandry, clinical signs, clinical examination, treatment for urolithiasis, and clinical outcome. The total number of cases in the 3 facilities was 101. As for species of tortoises, the most common was the African spurred tortoise (Centrochelys sulcata) with 42 cases (41.6%), followed by the Indian star tortoise (Geochelone elegans) with 30 cases (29.7%). Six other species were confirmed to have calculi. Almost all cases (99 cases, 98%) had a single calculus, and only 2 had multiple calculi. The prevalence of urolithiasis for the total number of tortoises having visited to one institution during the same period was 5.1%. Of the 86 cases that underwent calculi removal, 64 (74.4%) were successfully removed via the vent, and the efficacy of this method was confirmed. Nineteen cases (22%) were approached via plastronotomy, among which only 2 died postoperatively. In this study, we could not clarify the relationship between calculi formation and diets or other husbandry factors.

Animal models of naturally occurring stone disease

The prevalence of urolithiasis in humans is increasing worldwide; however, non-surgical treatment and prevention options remain limited despite decades of investigation. Most existing laboratory animal models for urolithiasis rely on highly artificial methods of stone induction and, as a result, might not be fully applicable to the study of natural stone initiation and growth. Animal models that naturally and spontaneously form uroliths are an underused resource in the study of human stone disease and offer many potential opportunities for improving insight into stone pathogenesis. These models include domestic dogs and cats, as well as a variety of other captive and wild species, such as otters, dolphins and ferrets, that form calcium oxalate, struvite, uric acid, cystine and other stone types. Improved collaboration between urologists, basic scientists and veterinarians is warranted to further our understanding of how stones form and to consider possible new preventive and therapeutic treatment options.

Management of nephrolithiasis by pyelotomy and pyeloscopy in an Asian small-clawed otter (Aonyx cinereus)

CASE DESCRIPTION

A captive adult sexually intact female Asian small-clawed otter (Aonyx cinereus) was evaluated because of diarrhea and signs of abdominal discomfort on arrival at the quarantine area of a zoological park.

CLINICAL FINDINGS

Radiographic and ultrasonographic examinations revealed the presence of a large nephrolith in the left kidney. Mild nephrolithiasis was detected in the right kidney. Results of hematologic and serum biochemical analyses were within references intervals. Intravenous pyelography was used for functional assessment of the urinary system and revealed normal renal excretory function bilaterally.

TREATMENT AND OUTCOME

Unilateral (left-sided) pyelotomy was selected as a treatment option to preserve maximal functional renal tissue. Pyeloscopy was successfully used for detection of some small nephroliths that were not removed by repeated flushing of the renal pelvis. Surgical treatment of the right kidney was not considered necessary. The otter recovered fully from anesthesia and surgery. Renal function was considered normal when assessed at 3 and 7 days and at 1 and 12 months after surgery.

CLINICAL RELEVANCE

To the authors' knowledge, pyelonephrotomy in otters has not been reported and may be considered as a potential surgical solution for nephrolithiasis. Pyeloscopy allowed the identification of small uroliths that were not removed by repeated flushing of the left renal pelvis following removal of the large nephroliths.

Urolithiasis and cystitis associated with Staphylococcus delphini group A and mortality in post-weaning mink kits (Neovison vison)

Mortality of mink kits represents a significant loss to production. However, causes of post-weaning mortality in mink kits in modern Danish mink production systems are still relatively poorly documented. We performed a cross-sectional mortality study on eight Danish mink farms including 1893 post mortem examinations of mink kits found dead or euthanized. We assessed the prevalence of cystitis and urolithiasis leading to mortality. Gross pathological findings as well as animal characteristics were recorded and associations with post mortem microbiology (using culture and MaldiTof-MS Vitek MS system) were investigated. Cystitis and/or urolithiasis were associated with death in 33 % (n = 476) and 37 % (n = 166) of the examined mink kits in 2015 and 2017. On farm level, the prevalence of cystitis and/or urolithiasis leading to mortality varied from 0.25 % to 1.27 % with a low overall mortality of 0.9-4.5 %. The bacterial agent most frequently isolated in post mortem bladder swabs from mink with a post mortem diagnosis of urolithiasis and cystitis was Staphylococcus delphini group A (51/283) with a significant (p < 0.0001, CI = [19.5;4745.7]) association to gross pathological findings in the urinary tract. Staphylococcus delphini group A was cultured from 70 % of the skin swabs obtained from apparently healthy mink euthanized at pelting (n = 222). In conclusion urinary tract disease (cystitis and urolithiasis) was the most prevalent post mortem diagnosis during the growth period and was associated with Staphylococcus delphini group A.

Update on Diseases in Chinchillas: 2013-2019

Chinchillas have been used mostly as fur animals and as animal models for human ontological diseases and only recently have been recognized as excellent, long-lived, and robust pet rodents. This review aims to provide updated information on emerging disease conditions in pet chinchillas, such as Streptococcus equi subsp zooepidemicus and Pseudomonas aeruginosa. Furthermore, this review article provides updated information on previously documented disorders, such as urolithiasis and middle ear disease, in chinchillas. This article is intended to serve as a complement to the current veterinary reference literature and to provide valuable and clinically relevant information for veterinarians treating chinchillas.

XANTHINE NEPHROLITHIASIS IN JUVENILE CAPTIVE GIANT OTTERS (PTERONURA BRASILIENSIS)

Nephrolithiasis has been reported in several aquatic mammals including bottlenose dolphins (Tursiops truncatus), small clawed otters (Amblonyx cinereus), European river otters (Lutra lutra), North American river otters (Lontra canadensis), northern elephant seals (Mirounga angustirostris), Florida manatees (Trichechus manatus latirostris), and California sea lions (Zalophus californianus). Compositions of calculi in previous cases were predominantly calcium oxalate or ammonium acid urate. Xanthine urolithiasis is rare in veterinary medicine. Primary cases (without exposure to xanthine dehydrogenase inhibitors) occur as a consequence of hereditary xanthinuria, although the causal mutation has only been discovered in a subset of cases. Five captive juvenile giant otters (Pteronura brasiliensis) from two facilities were diagnosed with nephrolithiasis: three siblings from one set of parents and two siblings from another pair. Serum analyte assays revealed renal compromise in affected individuals. Computed tomography (CT) confirmed the presence of nephrolithiasis in one individual. Postmortem evaluation identified extensive bilateral nephrolithiasis on gross necropsy in four of five cases. Calculus analyses identified 100% xanthine composition. Histologic examination revealed marked nephrolithiasis with associated tubular necrosis and gastric mineralization. Nutrient composition of the diet including mineral and purine content was assessed. No association between diet and nephroliths was found in this study. This is the first report of xanthine nephrolithiasis in aquatic mammals. The potential role of diet and genetics in xanthine nephrolithiasis in the small inbred population of giant otters under human care needs further investigation to assess the implications of this disease process for the long-term captive management of this species.

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.

Rats and Mice

This chapter provides an overview of the natural history, anatomy, physiology, clinical examination, common diseases, and treatment of rats (Rattus norvegicus) and mice (Mus musculus) in the context of veterinary medicine. Guidelines for the care and feeding of rats and mice can provide owners with information to help prevent disease in their pets. Useful techniques for restraint, clinical examination, and diagnostic sample collection are provided to aid veterinarians in thorough evaluation of these small rodents. Common diseases and treatments are discussed separately for each species, organized by organ system. Zoonotic diseases are also discussed to provide guidance for rat and mouse pet owners.

UROLITH PREVALENCE AND RISK FACTORS IN ASIAN SMALL-CLAWED OTTERS ( AONYX CINEREUS)

Uroliths (urinary stones) are routinely found in both domestic and exotic animals kept under human care. In zoos, Asian small-clawed otters (ASCOs, Aonyx cinereus) have been identified as being particularly prone to this disease. Risk factors are thought to be nutritional; however, recommendations contradict each other, depending on which physiological model was used. Our study aimed to determine the prevalence of uroliths in ASCOs under human care and to evaluate which feeding patterns and nutrients may be linked to their occurrence. Questionnaires were sent to zoos holding ASCOs in North America (AZA), Europe (EAZA), and Japan and Southeast Asia (Asia) asking about diets and medical histories of all ASCOs alive or dead within the last 10 yr. A risk-factor style binary logistic regression was conducted on these data. A total of 94 questionnaires were received; however, only 56 were usable (15.6% return rate), representing 161 otter cases. AZA had the significantly highest incidence of kidney stones (62.8%), followed by EAZA (12.9%) and Asia (9.4%). Age and calcium were risk factors, whereas crude protein and sodium were protective. Therefore, calcium may need to be controlled within their diet. A diet high in fish and crustaceans may be beneficial and is consistent with wild ASCO diets. The feline model may be the best choice out of other models; however, many factors cannot be compared with ASCO, such as urinary pH.

Hereditary xanthinuria in a goat

A 2-year-old mixed breed goat was presented for a 1-day history of anorexia and 1 week of weight loss. Serum biochemistry disclosed severe azotemia. Abdominal ultrasound examination showed decreased renal corticomedullary distinction, poor visualization of the renal pelves, and dilated ureters. On necropsy, the kidneys were small, the pelves were dilated, and the medulla was partially effaced by variably sized yellow nephroliths. Histologically, cortical and medullary tubules were distended by yellow-brown, multilayered crystals. Stone composition was 100% xanthine. Exonic sequencing of xanthine dehydrogenase (XDH) and molybdenum cofactor sulfurase (MOCOS) identified 2 putative pathogenic variants: a heterozygous XDH p.Leu128Pro variant and a homozygous MOCOS p.Asp303Gly variant. Variant frequencies were determined in 7 herd mates, 12 goats undergoing necropsy, and 443 goats from genome databases. The XDH variant was not present in any of these 462 goats. The MOCOS variant allele frequency was 0.03 overall, with 3 homozygotes detected. Hereditary xanthinuria is a recessive disorder in other species, but the XDH variant could be causal if the case goat is a compound heterozygote harboring a second variant in a regulatory region not analyzed or if the combination of the XDH and MOCOS variants together abolish XDH activity. Alternatively, the MOCOS variant alone could be causal despite the presence of other homozygotes, because hereditary xanthinuria in humans often is asymptomatic. Ours is the first report describing the clinical presentation and pathology associated with xanthine urolithiasis in a goat. The data support hereditary xanthinuria, but functional studies are needed to conclusively determine the causal variant(s).

Geobiology reveals how human kidney stones dissolve in vivo

More than 10% of the global human population is now afflicted with kidney stones, which are commonly associated with other significant health problems including diabetes, hypertension and obesity. Nearly 70% of these stones are primarily composed of calcium oxalate, a mineral previously assumed to be effectively insoluble within the kidney. This has limited currently available treatment options to painful passage and/or invasive surgical procedures. We analyze kidney stone thin sections with a combination of optical techniques, which include bright field, polarization, confocal and super-resolution nanometer-scale auto-fluorescence microscopy. Here we demonstrate using interdisciplinary geology and biology (geobiology) approaches that calcium oxalate stones undergo multiple events of dissolution as they crystallize and grow within the kidney. These observations open a fundamentally new paradigm for clinical approaches that include in vivo stone dissolution and identify high-frequency layering of organic matter and minerals as a template for biomineralization in natural and engineered settings.

An experimental model for calcium carbonate urolithiasis in goats

BACKGROUND

Calcium carbonate is a common urolith type in small ruminants with no high-yield experimental model to evaluate animal susceptibility or preventative measure response.

HYPOTHESIS

That novel plastic winged implants would allow accumulation and quantification of calcium carbonate calculus formation in goats on a high-calcium diet and identify individual variation between goats in the mass of calculi produced.

ANIMALS

Eight nonpregnant 3- and 4-year-old Boer-cross does, weighing 22.3-39.5 kg, determined to be healthy based on physical examination, were used in these experiments.

METHODS

Prospective cohort study for in vivo experimental model development. Implants were placed into the urinary bladder lumen in 8 goats over 2 evaluation periods. The alfalfa-based ration had a total ration Ca : P of 3.29 and 3.84 : 1, respectively. Urine was collected at 0, 28, 56, and 84 days in the 1st experiment; blood and urine at those timepoints in the 2nd experiment. For each evaluation period, the implants were removed 84 days after implantation and weighed. Accumulated calculi mass was calculated and compared between goats and was analyzed for composition.

RESULTS

Implant retention was 100% and 86% in the 2 studies. All goats with retained implants accumulated calcium carbonate at a mean implant gain per day across studies ranging from 0.44 to 57.45 mg. Two goats accumulated (0.44-7.65 mg/day and 33.64 & 57.45 mg/day) significantly more urolith material than the cohort across both studies (P = .047). No routine analytes on blood or urine were found to be explanatory for the difference observed.

CONCLUSIONS AND CLINICAL IMPORTANCE

These findings form a basis for implant and diet selection for use in future studies of urolithiasis development and for studies regarding individual susceptibility to urolithiasis.

PREVALENCE OF CYSTINURIA IN SERVALS ( LEPTAILURUS SERVAL) IN THE UNITED STATES

Cystinuria is a condition caused by defects in amino acid transport within the kidneys and small intestines. It has been reported in humans, dogs, domestic cats, ferrets, nondomestic canids, and nondomestic felids, including servals ( Leptailurus serval). Genetic mutations have been identified in dogs, humans, and domestic cats. Cystinuria usually follows an autosomal recessive inheritance, although it can be autosomal dominant and sex linked. The primary objective of this study was to screen urine samples dried on filter paper from captive servals in the United States for cystinuria by using the cyanide-nitroprusside screening test. A second objective was to determine whether cystinuria is inheritable in servals. Servals were initially recruited for the study by survey. Owners and institutions interested in participating were sent a second survey and filter paper for collecting urine samples. Samples were collected from 25 servals. One additional serval with confirmed cystine urolithiasis was added for a total sample size of 26 servals. Twenty-seven percent (7/26) were positive, 54% (14/26) were weakly positive, and 19% (5/26) were negative. Sex, reproductive status, and urine collection method had no significant association with test results. This condition is likely underreported in servals and should be ruled out in any serval with nonspecific signs of illness; neurologic signs such as lethargy, ataxia, or seizures; ptyalism; or signs of lower urinary tract disease such as dysuria, hematuria, stranguria, pollakiuria, or urethral obstructions.

Perineal urethrostomy to treat obstructive urolithiasis in a captive hand-raised steenbok (<i>Raphicerus campestris</i>)

The steenbok (Raphicerus campestris) is a small antelope of the family Bovidae native to the African continent. Urolithiasis, the formation of urinary calculi in the urinary tract, can be caused by a variety of factors such as diet, dehydration, infection and anatomical predisposition. Urolithiasis, with uroliths identified as magnesium calcium phosphate carbonate in composition, was diagnosed in a hand-reared 5-month-old steenbok. Perineal urethrostomy was performed as a component of the broad treatment regime that included fluid therapy, antibiotic and anti-inflammatory treatment. However, the animal died 4 days later as a result of systemic hypoxia and energy depletion because of stress and cachexia. The challenges of post-surgical treatment, the importance of positive energy balance in small ruminants under stressful circumstances, as well as the role of diet of hand-reared antelope in predisposition to urolith formation are highlighted.

No stone unturned: The presence of kidney stones in a skeleton from 19th century Peoria, Illinois

During the excavation of the 19th century Peoria City Cemetery (Peoria, Illinois), a skeleton of a female, aged 20-30 years old, was found with large, bilateral calcified masses in the abdominal region. The masses were analyzed by Fourier transform infrared (FTIR) spectroscopy, and the results compared to published clinical data in an effort to determine the etiology of the stones. The calcified masses were determined to be staghorn struvite uroliths, which commonly result from chronic urinary tract infection and likely impacted the overall health of this individual.

UROLITHIASIS IN A GROUP OF VISAYAN WARTY PIGS (SUS CEBIFRONS NEGRINUS)

Four cases of obstructive urolithiasis occurred in male Visayan warty pigs (Sus cebifrons negrinus) during a 12-mo period. One animal died, two were euthanized, and one was treated successfully with a tube cystotomy procedure and a subsequent urinary acidification diet. Uroliths from two cases of urethral obstruction were analyzed and confirmed as calcium carbonate. A fifth nonobstructive case was suspected in an adult female in which calcium carbonate crystalluria was diagnosed, and that case was resolved with medical management. Possible causes of these uroliths included reduced water intake, increased calcium in the diet through use of lucerne hay, and concurrent urinary tract infections. Changes to the diet and access to water were correlated with cessation of further cases, and no recurrence has been seen to date. To the authors' knowledge, this is the first report of calcium carbonate urolithiasis and the first use of a tube cystotomy in a nondomestic pig species.

Mineral Composition of Uroliths Obtained from Sheep and Goats with Obstructive Urolithiasis

Background

Knowledge of the mineral composition of the causative urolith is important to develop preventative strategies. Advances in analytic techniques have led to detection of urolith components not previously recognized.

Hypothesis/Objectives

The objectives of this study were to characterize uroliths in sheep and goats structurally and clinically. We hypothesized that amorphous magnesium calcium phosphate (AMCP) would be a naturally occurring urolith type in sheep and goats.

Animals

Forty‐nine sheep and goats presenting for obstructive urolithiasis from June 15, 2014 through June 14, 2016 were reviewed along with the demographic data of all small ruminants admitted during that same period.

Methods

Medical records were reviewed for demographic and historical data, and 36 uroliths obtained from these cases during diagnostic or therapeutic procedures were analyzed by infrared spectroscopy to determine chemical composition.

Results

AMCP is a naturally occurring urolith type in obstructed male sheep and goats and was the most common urolith type in this study, where it occurred as a majority component with struvite (39% of uroliths) or as a pure component (11%). Pure struvite was found in 1 urolith (2%). Calcium carbonate was the second most frequent urolith with 31% of uroliths being pure calcium carbonate.

Conclusions and Clinical Importance

This study demonstrates that uroliths, which appear consistent with struvite, could actually be calcium‐containing AMCP. Urolith analysis is critical in determining mineral content of uroliths to guide dietary recommendations for prevention.

Cystinuria Associated with Different SLC7A9 Gene Variants in the Cat

Cystinuria is a classical inborn error of metabolism characterized by a selective proximal renal tubular defect affecting cystine, ornithine, lysine, and arginine (COLA) reabsorption, which can lead to uroliths and urinary obstruction. In humans, dogs and mice, cystinuria is caused by variants in one of two genes, SLC3A1 and SLC7A9, which encode the rBAT and bo,+AT subunits of the bo,+ basic amino acid transporter system, respectively. In this study, exons and flanking regions of the SLC3A1 and SLC7A9 genes were sequenced from genomic DNA of cats (Felis catus) with COLAuria and cystine calculi. Relative to the Felis catus-6.2 reference genome sequence, DNA sequences from these affected cats revealed 3 unique homozygous SLC7A9 missense variants: one in exon 5 (p.Asp236Asn) from a non-purpose-bred medium-haired cat, one in exon 7 (p.Val294Glu) in a Maine Coon and a Sphinx cat, and one in exon 10 (p.Thr392Met) from a non-purpose-bred long-haired cat. A genotyping assay subsequently identified another cystinuric domestic medium-haired cat that was homozygous for the variant originally identified in the purebred cats. These missense variants result in deleterious amino acid substitutions of highly conserved residues in the bo,+AT protein. A limited population survey supported that the variants found were likely causative. The remaining 2 sequenced domestic short-haired cats had a heterozygous variant at a splice donor site in intron 10 and a homozygous single nucleotide variant at a branchpoint in intron 11 of SLC7A9, respectively. This study identifies the first SLC7A9 variants causing feline cystinuria and reveals that, as in humans and dogs, this disease is genetically heterogeneous in cats.

Risk factors for calcium carbonate urolithiasis in goats

OBJECTIVE

To identify demographic or signalment factors associated with calcium carbonate urolith formation in goats.

DESIGN

Retrospective case series and case-control study.

ANIMALS

354 goats with calcium carbonate uroliths (case animals) and 16,366 goats without urinary tract disease (control animals).

PROCEDURES

Medical records of the Minnesota Urolith Center were reviewed to identify case goats for which samples were submitted between January 1, 1984, and December 31, 2012. Control goats evaluated at US veterinary teaching hospitals in the same time period were identified by searching Veterinary Medical Database records. Age, breed, sex, reproductive status, geographic location, season, and anatomic location of collected uroliths were analyzed to identify risk or protective factors associated with calcium carbonate urolithiasis.

RESULTS

Nigerian dwarf goats had higher odds of developing calcium carbonate uroliths than did Pygmy goats (reference group). Several breeds had lower odds of this finding, compared with Pygmy goats; odds were lowest for mixed, Anglo-Nubian, and Toggenburg breeds. Breeds of African origin (Pygmy, Nigerian Dwarf, and Boer) comprised 146 of 275 (53%) case goats with data available. Goats of African descent had a higher risk of developing calcium carbonate uroliths than did goats of non-African descent (reference group). Males and neutered goats had higher odds of calcium carbonate urolithiasis, compared with females and sexually intact goats, respectively. Age category, geographic location, and season were associated with detection of calcium carbonate uroliths.

CONCLUSIONS AND CLINICAL RELEVANCE

Goats with calcium carbonate uroliths were typically neutered males, > 1 year of age, and of African descent. This study identified factors associated with calcium carbonate urolithiasis in goats; however, these associations do not allow conclusions regarding cause-and-effect relationships.

EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY AND ENDOSCOPIC URETERAL STENT PLACEMENT IN AN ASIAN SMALL-CLAWED OTTER (AONYX CINEREA) WITH NEPHROLITHIASIS

Urolithiasis is a significant disease concern in Asian small-clawed otters (Aonyx cinerea), with over 60% of captive animals affected. Bilateral ureteral stent placement, using endoscopic and fluoroscopic guidance, and extracorporeal shock wave lithotripsy (ESWL) were performed as salvage procedures in a 13-yr-old intact female Asian small-clawed otter following a 7-yr history of nephrolithiasis and progressive renal insufficiency. Following the procedure, radiographs revealed a slight shifting of urolith position, although a decrease in urolith mass was not observed. As a result of declining quality of life related to severe osteoarthritis, the otter was euthanized 5 wk after the procedure. While this treatment approach was unsuccessful in this case, the technique was clinically feasible, so ESWL and ureteral stent placement may remain a consideration for other individuals of this species presented earlier in the course of this disease.

The urothelium: anatomy, review of the literature, perspectives for veterinary medicine

Over time, much knowledge has been accumulated about the active role of the urothelium, principally in rodents and human. Far from being a mere passive barrier, this specialized epithelium can alter the ion and protein composition of the urine, is able to sense and respond to mechanical stimuli such as pressure, and react to mechanical stimuli by epithelial cell communication with the nervous system. Most of the specialized functions of the urothelium are linked to a number of morpho-physiologic properties exhibited by the superficial umbrella cells, including specialized membrane lipids, asymmetric unit membrane particles and a plasmalemma with stiff plaques which function as a barrier to most substances found in urine, thus protecting the underlying tissues. Moreover, the entire mucosa lining the low urinary tract, composed of urothelium and sub-urothelium, forms a functional transduction unit, able to respond to eso- and endogenous physical and chemical stimuli in a manner assuring an adequate functional response. This review will summarize the available information on each area of inquiry from a morpho-functional point of view. Possible considerations pertaining to species of veterinary interest are reviewed as well. The review was prepared consulting the electronic databases PubMed and Cab Abstracts and retrieving all pertinent reports and the relative reference lists, in order to identify any potential additional studies that could be included. Full-length research articles and thematic reviews were considered. Information on the urothelium of some domestic animal species was also included.

Nephrectomy in an Asian small-clawed otter (Amblonyx cinereus) with pyelonephritis and hydronephrosis secondary to ureteral obstruction

A 10-yr-old, captive, intact male Asian small-clawed otter (Amblonyx cinereus) with a history of bilateral nephrolithiasis was presented for acute-onset lethargy and inappetance of 5 days duration. On physical examination, the otter was about 8% dehydrated and a palpable fluid wave was present in the abdomen. An abdominal ultrasound revealed hydronephrosis of the left kidney and a hyperechoic structure present within the lumen of the left ureter, causing an obstruction. A urinalysis revealed struvite crystalluria, bacteriuria, and an elevated pH. Following 4 days of antibiotic therapy, a left ureteronephrectomy was performed. Upon opening the kidney to retrieve calculi, a large amount of purulent material was noted within the renal pelvis. To the authors' knowledge, this is the first documented case of a nephrectomy in an Asian small-clawed otter. Nephrectomy should be considered as a viable option for treatment of ureteral obstruction, hydronephrosis, or severe pyelonephritis.

Urolithiasis in a captive group of Tammar wallabies (Macropus eugenii)

Urolithiasis is a well-known disease of the urogenital system in domestic animals, and it has also been described in captive and free-ranging wildlife. This article reports 15 cases of urolithiasis in a captive group of Tammar wallabies (Macropus eugenii) between 2004 and 2011. The analyzed stones were composed of pure calcium carbonate (n = 5), calcium carbonate with traces of calcium phosphate (n = 6), carbonate apatite (n = 2), and carbonate apatite mixed with calcium oxalate (n = 2). In 12 out of 15 cases uroliths were situated only in the renal pelvis; in two cases they were found in the renal pelvis and the ureter; while in one case in the ureter only. No common infectious agents were identified either by microbiological or histopathological methods. Although the exact cause remains unknown, the repetitive occurrence of calcium carbonate urolithiasis suggests husbandry-related causes. To the best of the authors' knowledge, this is the first report on recurrent appearance of urolithiasis in a captive group of Tammar wallabies.

Recurrent calcium phosphate urolithiasis in a black-and-white ruffed lemur (Varecia variegata)

An adult intact male black-and-white ruffed lemur (Varecia variegata) suffered recurrent bouts of urethral blockage over a 3-yr period caused by calcium phosphate (apatite form) uroliths. Surgical intervention was required in two of the three instances. Various attempts at medical management failed to control formation of the stones, and the underlying etiology remains unclear. In addition, there have been consistent, multiple, unchanging renal mineralizations over the course of the case. Medical management failed to significantly alter the urinary pH; although, to date, no further problems have been noted. To the authors' knowledge, this is the first known report of calcium phosphate stones in a prosimian species.

Update on diseases of chinchillas

Chinchillas have been successfully maintained in captivity for almost a century. They have only recently been recognized as excellent, long-lived, and robust pets. Most of the literature on diseases of chinchillas comes from farmed chinchillas, whereas reports of pet chinchilla diseases continue to be sparse. This review aims to provide information on current, poorly reported disorders of pet chinchillas, such as penile problems, urolithiasis, periodontal disease, otitis media, cardiac disease, pseudomonadal infections, and giardiasis. This review is intended to serve as a complement to current veterinary literature while providing valuable and clinically relevant information for veterinarians treating chinchillas.

Cystine urolithiasis in a caracal (Caracal caracal)

In July 2009, a 14-yr-old male caracal (Caracal caracal) at the National Zoological Gardens of South Africa was found, on abdominal ultrasound, to have a single large cystolith. The cystolith was removed, and the composition was determined to be 100% cystine. Blood and urine samples were also collected from three other apparently healthy caracals at the zoo and were submitted, together with the samples from the affected animal, for analysis using gas chromatograph mass spectrometry for cystine, lysine, alanine, and ornithine levels. The cystine levels in the urine, the fractional excretion of cystine, and the normalized excretion of cystine (micromol/g of creatinine) were all higher in the affected caracal than in the healthy animals. Only a single other case of cystine urolithiasis has been previously reported in any wild felid in the literature.