Relationship of nutritional factors to the cause, dissolution, and prevention of canine uroliths

Rescue and rehabilitation of maned wolf (Chrysocyon brachyurus) in Paraguay: Case description

The maned wolf, Chrysocyon brachyurus, is the largest South American canid, with a natural distribution that stretches across Peru, Bolivia, Brazil, Argentina, Paraguay and Uruguay. The present study reports the case of a rescued specimen of maned wolf that underwent a rehabilitation process in Paraguay, starting in October 2020 with its rescue, and finalising in May 2021 with the reintroduction. Herein, we document findings regarding the general management, biometrics, feeding and environmental enrichment; chemical immobilisation and monitoring; haematology, blood biochemistry and specific serology-relevant pathogens; skin examination and bone marrow cytology; orthopaedic, ophthalmological and dental evaluation; abdominal and cardiac ultrasonography; radiology and copro-parasitology. Main findings include the feeding habits of the individual and enrichment opportunities. The animal weighed 7 kg on arrival, with an estimated age of 5 months, and 18 kg on reintroduction, with an estimated age of 1 year. The animal tested negative to serologic tests for Brucella canis, Dirofilaria, canine distemper, Toxoplasmosis and canine parvovirus. Leptospira testing showed antibodies against L. grippotyphosa on both samplings, L. wolffi and L. ictero on the first sampling, and L. pomona on the second sampling. Abdominal organs were examined and measured through ultrasound evaluation and kidneys showed no alterations. Echocardiography showed preserved mitral, tricuspid and aortic valve flows, but turbulent pulmonary valve flow. Copro-parasitology reported the presence of Lagochilascaris sp. and Balantidium sp. All the information gathered aided in diagnosing the health status of the individual, and the response to environmental enrichment helped assess the behaviour, which led to the suggestion of reintroducing the animal. These data constitute the first published health check of a maned wolf in Paraguay, which can contribute to the species' conservation in the country. The protocol presented in this study can serve as a basis for developing an action plan for the maned wolf in Paraguay.

Cystinuria in Dogs and Cats: What Do We Know after Almost 200 Years?

The purpose of this review is to summarize current knowledge on canine and feline cystinuria from available scientific reports. Cystinuria is an inherited metabolic defect characterized by abnormal intestinal and renal amino acid transport in which cystine and the dibasic amino acids ornithine, lysine, and arginine are involved (COLA). At a normal urine pH, ornithine, lysine, and arginine are soluble, but cysteine forms a dimer, cystine, which is relatively insoluble, resulting in crystal precipitation. Mutations in genes coding COLA transporter and the mode of inheritance were identified only in some canine breeds. Cystinuric dogs may form uroliths (mostly in lower urinary tract) which are associated with typical clinical symptoms. The prevalence of cystine urolithiasis is much higher in European countries (up to 14% according to the recent reports) when compared to North America (United States and Canada) where it is approximately 1-3%. Cystinuria may be diagnosed by the detection of cystine urolithiasis, cystine crystalluria, assessment of amino aciduria, or using genetic tests. The management of cystinuria is aimed at urolith removal or dissolution which may be reached by dietary changes or medical treatment. In dogs with androgen-dependent cystinuria, castration will help. In cats, cystinuria occurs less frequently in comparison with dogs.

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.

Prediction of Mineral Composition in Commercial Extruded Dry Dog Food by Near-Infrared Reflectance Spectroscopy

The pet food industry is interested in performing fast analyses to control the nutritional quality of their products. This study assessed the feasibility of near-infrared spectroscopy to predict mineral content in extruded dry dog food. Mineral content in commercial dry dog food samples (n = 119) was quantified by inductively coupled plasma optical emission spectrometry and reflectance spectra (850-2500 nm) captured with FOSS NIRS DS2500 spectrometer. Calibration models were built using modified partial least square regression and leave-one-out cross-validation. The best prediction models were obtained for S (coefficient of determination; R² = 0.89), K (R² = 0.85), and Li (R² = 0.74), followed by P, B, and Sr (R² = 0.72 each). Only prediction models for S and K were adequate for screening purposes. This study supports that minerals are difficult to determine with NIRS if they are not associated with organic molecules.

Urolitíase por cistina em cães no Brasil

O presente trabalho tem como objetivo relatar três casos de urolitíase canina por cistina, atendidos no Hospital Veterinário da Universidade Estadual de Londrina entre o período de 2007 a 2009. O diagnóstico de urolitíase foi baseado na anamnese, no exame físico e nos exames laboratoriais e radiográficos, e a confirmação do tipo de urólito envolvido foi realizada no Centro de Urólitos de Minnesota-USA, por meio de análise quantitativa, revelando cálculos puros de cistina. A terapia instituída incluiu a remoção cirúrgica dos urólitos e a prevenção de recidivas, por meio do aumento da solubilidade da cistina na urina com dieta comercial própria, aumento da ingestão hídrica e alcalinização medicamentosa da urina.

An integrated epidemiologic and radiographic algorithm for canine urocystolith mineral type prediction

Research involved 2 databases. One database (occurrence frequency) comprised the age, breed, gender and urocystolith mineral type (pure chemical types only) from 2041 canine patients submitted to the Minnesota Urolith Center. The other database (imaging) comprised the maximum size, surface (rough, smooth, and smooth with blunt tips), shape (faceted, irregular, jackstone, ovoid, and round) and internal architecture (lucent center, random-nonuniform, and uniform) from 434 canine patients imaged in a urinary bladder phantom. The imaging database was a partial subset of the occurrence frequency database. Imaging techniques simulated were survey radiography and double contrast cystography. The databases were compared using multivariate analysis techniques. Equations were developed to use clinically-relevant characteristics (age, breed, gender, maximum size, surface, shape, and internal architecture) to predict urocystolith mineral types. The goal was to assess the accuracy of the various techniques in predicting the urocystolith mineral types. The combination of signalment (age, breed, gender) and simulated survey radiographic findings does not improve mineral type prediction accuracy (average across all mineral types is 69.9%) beyond that achievable with signalment alone (average across all mineral types is 69.8%). However, the combination of signalment and double contrast cystography does improve mineral type prediction accuracy (average across all mineral types is 75.3%). For comparison, mineral type prediction accuracy without signalment from survey radiographs only was 65.7% across all mineral types. The clinical utility of the algorithm is the option to distinguish urocystolith mineral types requiring surgical vs. medical treatment.

Relevance of sonographic artifacts observed during in vitro characterization of urocystolith mineral composition

Nine pure mineral type canine uroliths (bladder or urethral origin only) were imaged ultrasonographically using 3.5 MHz, 5.0 MHz, and 7.5 MHz fixed focus, mechanical sector transducers in a urinary bladder phantom. The uroliths studied were those composed of 100% magnesium ammonium phosphate, calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate appatite, and calcium hydrogen phosphate dihydrate (brushite), ammonium acid urate, sodium acid urate, cystine, and silica. The occurrence of both reverberation/streak and acoustic shadowing artifacts were compared to urocystolith mineral type (classified by effective atomic number), urocystolith width, urocystolith height (thickness), and ultrasonographic imaging frequency. No predictable relationship was found between either of the artifacts seen beyond the urocystolith (reverberation/streak or the acoustic shadowing) and urocystolith mineral type. There was no statistical relationship between the occurrence of reverberation/streak artifact and the size (width or height) of the urocystolith or the ultrasonographic frequency. There was, however, a statistically relevant relationship between ultrasonographic imaging frequency and the occurrence of acoustic shadowing and between urocystolith height (thickness) and the occurrence of acoustic shadowing. However, regardless of ultrasound frequency, acoustic shadowing was observed less than 35% of the time in any of the urocystolith mineral types examined. Based on the imaging of the bladder phantom supporting apparatus (7.0 mm bolts covered by plastic), the accurate characterization of a curved object surface directly facing the transducer was found to be directly related to the frequency of sound used for imaging and at best predictably limited to curved vs flat. Accurate measurement of the maximum transverse dimension of an echogenic curved object or accurate characterization of the lateral borders of such an object was considered unlikely with general ultrasonographic equipment of the frequencies studied. Therefore, detailed architectural characterization of urocystoliths suitable for mineral composition prediction is considered highly unlikely with general pulse-echo ultrasonographic techniques.

Medical dissolution of struvite nephrolithiasis using amino acid preparation in dogs

A new chemolytic therapy with amino acid preparation was tried for use on struvite renal stones in two dogs, which were admitted to Azabu University Veterinary Teaching Hospital. No other special diet, for the purpose of dissolving the stones, was fed during the treatment. Dissolution of the stones began at week 1, and no stone was detected on radiography at week 4 in both cases. The amino acid preparation thereafter has been administered every 2-3 days to prevent formation of the stones. After 6 months from treatment, complete dissolution was confirmed, and no relapse has been observed. Therefore, it is concluded that chemolytic therapy with amino acid preparation might be useful for the treatment of nephrolithiasis with struvite renal stones in dogs.

Loss of urocystolith architectural clarity during in vivo radiographic simulation versus in vitro visualization

Urocystoliths of 9 mineral types from 434 canine patients submitted to the University of Minnesota Urolith Bank were imaged in a urinary bladder phantom. Imaging techniques simulated were survey radiography and double contrast cystography. Morphologic characteristics visually observed in vitro or by interpretation of high-resolution specimen radiographs were compared to those seen using the simulated in vivo imaging techniques. Shape characteristics that were accurately detected > or = 25% of the time on simulated survey or double contrast radiography were faceted, irregular, jackstone, ovoid, and round. Surface characteristics that were accurately detected > or = 25% of the time on simulated survey or double contrast radiography were rough, smooth, and smooth with blunt tips. Internal architecture characteristics that were accurately detected > or = 25% of the time on simulated survey or double contrast radiography were lucent center, random-nonuniform, and uniform. Shapes such as bosselated, faceted-ovoid, and rosette; surfaces such as botryoidal, and knife-edged; and internal architecture characteristics such as dense center, dense shell, laminated, and fissures were of almost no value either due to poor detectability or poor accuracy of recognition. Based on optimized simulated survey and double contrast radiographic procedures, it appears that a number of shape, surface, and internal architecture characteristics may be of limited or no value in discriminating among urocystolith mineral types under clinical circumstances. Shapes and surfaces were more accurately characterized by the simulated double contrast technique, but for internal architecture, the simulated survey radiographic technique seemed slightly superior overall.

Contrast medium-related artifacts observed during in vitro radiographic characterization of urocystolith mineral composition

Nine pure mineral types of canine uroliths (bladder or urethral origin only) were exposed to sequential increasing concentrations of iodinated, radiographic contrast medium in petri dishes. The uroliths studied were those composed of 100% magnesium ammonium phosphate, calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate appatite, and calcium hydrogen phosphate dihydrate (Brushite), ammonium acid urate, sodium acid urate, cystine, and silica. Two phenomena were observed. First, there was a tendency for selected urocystoliths to undergo radiopacity augmentation beyond that expected for just contrast medium superimposition. This was termed, contrast medium adhesion, which persisted despite repeated washing of the urocystoliths. Second, there was a tendency for bubbles to form on or near selected urocystolith chemical types. These observations prompted careful scrutiny for their occurrence in subsequent clinical simulation of radiographic procedures using these same urocystoliths in a urinary bladder phantom. Imaging techniques simulated were survey radiography, pneumocystography, double contrast cystography (two iodine concentrations). The contrast medium adhesion occurrence found in the petri dish studies was compared to urocystolith mineral type. Similar comparisons were made for contrast medium adhesion occurrence in the bladder phantom. The detection of contrast medium adhesion in the bladder phantom differed from that observed in the petri dish experiments. While contrast adhesion occurred across a fairly broad range of the urocystolith mineral types in the petri dish studies, it was observed primarily for sodium acid urate and cystine urocystoliths in the bladder phantom. Prompted by the observation of bubbles in association with a limited number of urocystolith types in the petri dish studies, bubble occurrence in the bladder phantom was compared to the urocystolith type. Bubble formation on or near the urocystoliths, although uncommonly observed, was seen only with either cystine or silica urocystoliths. The potential clinical utility and clinical caveat aspects of these phenomena are discussed.

Urocystolith detection: comparison of survey, contrast radiographic and ultrasonographic techniques in an in vitro bladder phantom

Urocystoliths of 9 mineral types from 437 canine patients submitted to the University of Minnesota Urolith Bank were imaged in a urinary bladder phantom. Imaging techniques simulated were survey radiography, pneumocystography, double contrast cystography (two iodine concentrations) and real-time ultrasonography (3.5 MHz, 5.0 MHz, 7.5 MHz). Imaging techniques were compared for accuracy of urocystolith detection, accuracy of urocystolith enumeration, and tendencies for over or undercounting. Across urocystolith mineral types, the false negative rates (no urocystoliths detected in a given case) for survey radiographs range from 2 to 27%. Pneumocystographic techniques are one-half as likely to yield false negative results as are survey radiographic techniques. Underestimates of urocystolith numbers and false negatives are likely using 80 mg iodine/ml double contrast cystography because calcium-based urocystoliths are isopaque in this contrast medium dilution. The 200 mg iodine/ml double contrast cystographic techniques are unlikely to yield false negative diagnoses even for very small (< or = 1.0 mm) urocystoliths and is comparable to pneumocystography for detection and slightly better for enumeration. The likelihood of an ultrasonographic false negative for urocystoliths decreases with increasing MHz. Under optimal conditions using a 7.5 MHz mechanical sector transducer, the false negative rates were comparable to double contrast cystography, but rates increased notably with lower MHz transducers.

Medical dissolution and prevention of canine struvite urolithiasis. Twenty years of experience

Two types of canine struvite uroliths have been recognized: infection-induced struvite is the most common type; sterile struvite is uncommonly recognized. Infection-induced struvite is most commonly associated with urease-producing staphylococcal UTI. For dogs that qualify, medical dissolution is an effective method of treatment. Medical dissolution protocols encompass: (1) eradication or control of UTI; (2) use of calculolytic diets; and (3) administration of urease inhibitors to patients with persistent UTI caused by urease-producing microbes.

Medical dissolution and prevention of canine uroliths. Seven steps from science to service

For millennia, removal of uroliths has been the province of the surgeon. However, a paradigm shift in management of canine uroliths occurred beginning in 1973. Translating the science associated with medical dissolution of canine uroliths into a form that would serve companion animals involved the interdependent knowledge, skills, and desire of many individuals. By practicing the principles of being proactive, defining clear objectives, agreeing how to accomplish these objectives, and empathetically listening to each others ideas and concerns, the surgical removal of uroliths will one day become a subject of historic interest.

Canine and feline nephrolithiasis. Epidemiology, detection, and management

Calcium oxalate (39%) and struvite (33%) were the predominant mineral types in canine nephroliths submitted to the Minnesota Urolith Center. Urate salts (12%) and calcium phosphate (2%) occurred less frequently. Provided they are not causing obstruction, struvite nephroliths may be dissolved with medical protocols. Although there are no dissolution protocols for nephroliths containing calcium, risk-benefit ratios should be considered before proceeding with surgery.

Canine cystine urolithiasis. Cause, detection, treatment, and prevention

Cystine uroliths are a sequela to cystinuria, an inherited renal tubular defect in reabsorption of cystine and some other amino acids. At the Minnesota Urolith Center, 67 breeds of dogs were identified, including English Bulldogs, Dachshunds, Mastiffs, and Newfoundlands. In some dogs, the severity of cystinuria may decline with advancing age. Current recommendations for dissolution of cystine uroliths include various combinations of diet modification, diuresis administration of 2-MPG, and alkalinization of urine.

Management of urocystoliths by voiding urohydropropulsion

Voiding urohydropropulsion is a nonsurgical method of removing uroliths from the urinary bladder. Any urocystolith of sufficient size to pass through the distended urethral lumen can be safely and effectively removed by this new technique. Compared to cystotomy, voiding urohydropropulsion offers several advantages: urolith removal can be performed in minutes, anesthetic period is shorter, postprocedural dysuria and hematuria are less severe, and it provides greater success for complete removal of small urocystoliths. This technique is not suitable for removal of large urocystoliths or uroliths that become lodged in the urethral lumen.