Urinary acidification in the prevention and treatment of feline struvite urolithiasis

Two groups of 12 cats were fed ad libitum an experimental dry expanded ration high in magnesium (0.37%, dry matter basis) and similar to most commercial dry cat foods in all other nutrients. The diet of one of the groups contained 1.5% ammonium chloride, which was added to the diet before processing. Urethral obstruction developed twice in 7 of the 12 cats fed the ration without ammonium chloride. Of the 5 remaining cats in that group, 2 had calculi in the urinary bladder and urethra at necropsy. In contrast, only 2 of the 12 cats fed the ration containing ammonium chloride had urethral blockage once; neither cat had another blockage. Both cats had been catheterized twice as paired controls before urethral obstruction. One of these 2 cats died from a urinary tract infection apparently introduced through the indwelling catheter, and at necropsy there were 2 small calculi in the urethra. At the end of the study, only 1 other cat fed the ammonium chloride diet had a calculus in the urinary bladder at necropsy; this cat had not had a urethral obstruction throughout the study. After each cat had 2 urethral blockages, its diet was changed. Four cats were fed the ration containing ammonium chloride and 3, a dry, commercial ration. Of the 4 cats fed the diet containing ammonium chloride, none developed another urethral obstruction within 6 months, and at necropsy, no calculi were in the urinary bladder or urethra. Two of the 3 cats fed the commercial ration experienced urethral blockage within 3 months. These 2 cats were then fed the diet containing ammonium chloride.(ABSTRACT TRUNCATED AT 250 WORDS)     

EFFECTS OF BLADDER DISTENTION ON CANINE AND FELINE RETROGRADE URETHROGRAPHY

Retrograde urethrography with viscous contrast medium was performed in male and female dogs and cats before and after bladder distention. The viscosity of commercially prepared contrast medium was increased by addition of an aqueous lubricant. The diameter of the proximal urethra of female dogs (regions 1 and 2) was larger during urethrography (p<0.05) following bladder distention. The diameter of regions 1 and 2 of the proximal uretha of female cats in lateral recumbency was larger during urethrography (p<0.05) following bladder distention. The diameter of the distal urethra of female dogs and cats was not significantly different before or after bladder distention. The diameter of the prostatic urethra of male dogs was larger (p<0.003) following bladder distention. The diameter of the membranous and penile urethra of male dogs was not significantly different before or after urinary bladder distention. Similarly, the diameter of the urethral lumen in male cats was not significantly different before or after bladder distention. The increased viscosity of the contrast medium due to the aqueous lubricant failed to distend all areas of the male and female canine and feline urethra maximally during urethrography when the bladder was not distended. On the basis of the results of this study, the authors recommend urinary bladder distention with a lubricant-free positive contrast medium to generate intravesical hydrostatic pressure sufficient to induce urethral distention. The degree of bladder distention should be determined by digital palpation.     

Management of traumatic urethral rupture in 11 cats using primary alignment with a urethral catheter

OBJECTIVE: To assess the management of traumatic urethral ruptures using a systematic attempt at urethral catheterisation. METHODS: Eleven cats that had been diagnosed with a traumatic urethral rupture over a five-year period were included in this study. Rupture was assessed by positive-contrast retrograde urethrography. An attempt was made to manage these ruptures by placing an indwelling urethral catheter. RESULTS: The placement of an indwelling urethral catheter, could be performed in 10 out of 11 cats, which indicated a partial rupture. In one cat, catheterisation was not possible because of complete urethral rupture. A urethral catheter was placed into the urinary bladder via the urethra in five animals. In the other five animals, urethral catheterization required cystotomy using a modified 'inside to outside' technique. Urethral catheter removal occurred between five and 14 days after placement. Urethral healing was accomplished in all cases of catheterisation with a good outcome in eight of the 10 cats. Two cats showed clinical signs related to stricture formation during the follow-up period (seven to 72 months). Retrograde urethrography provided a definitive diagnosis of partial rupture in only six of the 10 cases of partial rupture. CLINICAL SIGNIFICANCE: Results suggested that primary alignment with the placement of a urethral catheter should be attempted for the management of traumatic urethral ruptures in cats. Gentle urethral catheterisation seems to be an effective procedure for diagnosing and dealing with partial urethral rupture in cats. Clinical stricture formation can occur, but the risk does not seem to be high. Further studies are warranted in order to define the ideal duration for maintenance of an indwelling urethral catheter in cases of traumatic partial urethral rupture.     

Urethral conformation and position in relation to urinary incontinence in the bitch.

The conformation of the urethra, the position of the bladder neck and the distance between the external urethral orifice and the cranial pubic brim were compared in 30 continent and 30 incontinent bitches with incompetence of the urethral sphincter mechanism, using the measurements made from vagino-urethrograms. The bladder neck was significantly (P less than 0.001) further caudal in incontinent dogs than in continent dogs. Its position was not affected by neutering and could not be explained by the degree of urethral curvature. The distance from the external urethral orifice to the cranial pubic brim was correlated (P less than 0.001) with bodyweight but was not significantly different in the continent and incontinent bitches. In neutered animals, the distance between the cranial pubic brim and the external urethral orifice was significantly (P less than 0.05) shorter than in entire animals.     

Effects of urinary bladder distension on the length of the dog and cat urethra

Urethral lengths were determined in male and female cats and in female dogs from positive contrast retrograde urethrocystograms at 2 levels of urinary bladder distension. Urethral lengths were longer on urethrograms obtained after urinary bladder distension in female cats and in 7 of 8 female dogs. The intrapelvic and penile urethra were longer after bladder distension in 4 of 6 male cats. In female cats, urethral lengths significantly increased (P less than 0.05) after urinary bladder distension.     

ULTRASONOGRAPHIC APPEARANCE OF URETHRAL TRANSITIONAL CELL CARCINOMA IN TEN DOGS

The mucosal margin of the urethra is best assessed by positive contrast urethrography, but ultrasonography offers complementary information such as urethral wall thickness and size of medial iliac lymph nodes. Ultrasonography of the urethra is quick, noninvasive and does not require sedation or general anesthesia. In patients with complete urethral obstruction, ultrasonography may be the only way to image the urethra. Twelve dogs which were presented to Tufts University School of Veterinary Medicine with clinical signs referable to the urinary bladder, urethra or vagina were examined ultrasonographically. Seven were neutered females and five were neutered males. Each dog had a hyperechoic, nonshadowing line at the epithelial surface of the proximal urethra. In the seven female patients and one of the males, the urethral wall was also thick and hypoechoic to surrounding tissue. In the other males, the urethral epithelial changes were at the level of the prostate, and the limits of the urethra were not visible. In six dogs, the urethral change was the only abnormality seen, while in six, bladder wall, bladder luminal and/or prostatic parenchymal changes were also detected. Three patients had hydronephrosis, and one had enlarged medial iliac lyumph nodes. Biopsies were obtained via suction with urinary catheterization (n = 6), exploratory celiotomy (n = 3), urethroscopy (n = 2), or at post-mortem (n = 1). A histopathologic diagnosis of urethral transitional cell carcinoma was obtained in ten dogs. The ultrasonographic appearance was not pathognomonic for transitional cell carcinoma, as one dog with transitional cell dysplasia and one dog with severe ulcerative and necrosupperative cystitis and urethral stricture had similar findings.     

Urethral sphincter mechanism incompetence in the male dog: importance of bladder neck position, proximal urethral length and castration

The radiographs of 37 incontinent adult male dogs with urethral sphincter mechanism incompetence were compared with those of 28 control dogs to determine if, as in the bitch, differences in bladder neck position and urethral length were implicated in the pathophysiology of urethral sphincter mechanism incompetence. Bladder neck position was significantly different; compared with continent dogs, incontinent animals were significantly more likely (P<0.005) to have intrapelvic than intra-abdominal bladder necks. However, after allowing for the influence of body size, and unlike the situation in the bitch, there was no significant difference in proximal urethral length between the two groups. Bladder neck position was significantly related to prostate size (P<0.001) and it is suggested that this is one reason why castrated male dogs are more prone to urethral sphincter mechanism incompetence than entire animals. A logistic regression analysis revealed that both bladder neck position and castration status were significant risk factors for incontinence and that they appeared to be acting independently of each other.     

Urethroscopy and laser lithotripsy for the diagnosis and treatment of obstructive urolithiasis in goats and pot-bellied pigs

OBJECTIVE: To explore the use of urethral endoscopy and laser lithotripsy in the diagnosis and management of urolithiasis in goats and pot-bellied pigs. DESIGN: Prospective clinical study. ANIMALS: 16 male goats and 6 male pot-bellied pigs with dysuria. PROCEDURE: Abdominal ultrasonography and urethral endoscopy were performed on all 22 animals. Endoscopic-guided holmium:yttrium-aluminum-garnet laser lithotripsy was performed in 3 goats and 2 pot-bellied pigs. RESULTS: Urolithiasis was identified in 15 goats and 5 pot-bellied pigs. Primary urinary bladder paralysis and cystitis were identified in the remaining pot-bellied pig and goat. Mean bladder diameters of obstructed small- and large-breed goats were 7 and 9.5 cm, respectively. The mean bladder diameter of obstructed pot-bellied pigs was 9.5 cm. Five of 20 animals with obstructive urolithiasis had severe urethral necrosis or stricture formation at the time of urethroscopy. All of these animals were euthanatized within 6 months because of persistent dysuria. When used, laser lithotripsy successfully fractured the distally located obstructing stones in the 3 goats and 2 pot-bellied pigs. CONCLUSIONS AND CLINICAL RELEVANCE: Urethral endoscopy is useful for evaluating urethral patency in goats and pot-bellied pigs. Examination of the urethral mucosa following relief of urethral obstructions aids in the assessment of the long-term prognosis for urethral stricture. Urethral endoscopy also expands the therapeutic options for management of urolithiasis by providing a route for conducting laser lithotripsy. Laser lithotripsy proved to be safe and effective for clearing distally located calculi refractory to removal by traditional urethral flushing. Lithotripsy application is restricted to calculi lodged in the urethra.     

Ruptured urinary bladder attributable to urethral compression by a haematoma after vertebral fracture in a bull

Background

In male cattle, rupture of the urinary bladder is usually associated with urethral obstruction by uroliths. Less common causes include urethral compression or stricture. This case report describes the findings in a young Limousion breeding bull with rupture of the urinary bladder because of urethral compression by a haematoma after coccygeal fracture.

Case presentation

The bull had been introduced into a 40-head Red-Holstein herd one week before being injured. One week after introduction to the herd, the bull had an acute onset of anorexia and he was referred to the clinic. There was marked abdominal distension, reduced skin turgor and enophthalmus. The serum concentration of urea and creatinine was increased. Ultrasonographic examination revealed severe ascites and abdominocentesis yielded clear yellow fluid with high urea and creatinine concentrations, which supported a diagnosis of uroperitoneum. The bull was euthanatized because of a poor prognosis. Postmortem examination revealed a comminuted fracture of the first two coccygeal vertebrae associated with a massive haematoma that obstructed entire pelvic cavity. The haematoma compressed the urethra thereby preventing outflow of urine, which resulted in a 5-cm tear ventrally at the neck of the bladder. It was assumed that the newly-introduced bull had sustained the vertebral fractures when he was mounted by a cow.

Conclusions

The present case study serves to expand the differential diagnosis of urinary bladder rupture. Therefore, in addition to obstructive urolithiasis, compression and stricture of the urethra might be considered in male cattle with uroperitoneum.     

Immediate urodynamic and anatomic response to colposuspension in female Beagles

OBJECTIVE: To characterize urodynamic function and anatomy before and after colposuspension in anesthetized female Beagles. ANIMALS: 12 adult female Beagles. PROCEDURE; During general anesthesia (thiopental sodium induction and halothane maintenance), urethral pressure profiles, leak point pressure measurements with a 50-ml bladder volume, positive contrast cystograms, and retrograde vaginourethrocystograms were performed. A caudal midline laparotomy was used to perform colposuspension. Urodynamic and radiographic studies were repeated after surgery. RESULTS: Leak point pressures were increased (120 to 168.9 cm H2O), and maximum urethral closure pressures decreased (43.7 to 19.3 cm H2O ) after colposuspension. The urethra and bladder were moved cranially; the external urethral orifice was positioned closer to the pelvic cavity, and the neck of the bladder was positioned more cranially into the abdomen. Length of the urethra, as measured by use of vaginourethrocystograms, was increased by 3%. As measured by use of urethral pressure profiles, total profile length was increased by 19.9%, and functional profile length was increased by 19.2%. CONCLUSIONS AND CLINICAL RELEVANCE: Increased leak-point pressure correlated with the expected clinical improvement attributable to colposuspension. Increased exposure of the urethra to abdominal and pelvic cavity pressures may be the mechanism by which incontinent dogs become continent after colposuspension. Results of the leak-point pressure test may correlate with clinical behavior before and after colposuspension for treatment of incontinence.     

Modified perineal urethrostomy using preputial mucosa in cats

A modified perineal urethrostomy was performed in 14 males cats with partial or complete urethral obstruction. Follow-up information was available for 2 to 18 months. By use of this method, the preputial tissues were preserved, and the penile urethra was anastomosed to the preputial mucosa to enlarge and lengthen the urethra. Urine flow was reestablished in all cats without evidence of urethral stenosis or other major complications. Appearance of the perineal region and prepuce was not substantially altered.     

Congenital urinary incontinence in cats: a review of 19 cases.

Nineteen cases of feline congenital urinary incontinence (10 cats with ureteral ectopia and nine with incompetence of the urethral sphincter mechanism) are reviewed. The 10 cats with ureteral ectopia are considered together with 13 from previous reports. There was no apparent breed predisposition. Most of the 23 cats were presented for urinary incontinence but two of them were continent. Thirteen were females and ectopia was unilateral in 13 and bilateral in 10. Twenty-eight of 31 ectopic ureters terminated in the urethra. The commonest complication was hydroureter/hydronephrosis (10 cases). Eighteen of the cats were treated surgically, 13 by ureteral transplantation, four by ureteronephrectomy and one by ligation of the renal blood vessels; 16 of them were cured by surgery. Congenital urethral sphincter mechanism incompetence has not been reported previously in the cat. Nine cases are presented and the urethras of all were markedly hypoplastic. A common concomitant abnormality was vaginal aplasia, with the uterine horns terminating in the dorsum of the bladder. Bacteriuria was more common in this group than in the cats with ureteral ectopia.     

The Immediate Effect of Colposuspension on Resting and Stressed Urethral Pressure Profiles in Anaesthetized Incontinent Bitches

The aim of this study was to document what changes in the resting and stressed urethral pressure profile occur in the incontinent bitch with urethral sphincter mechanism incompetence (SMI) immediately after colposuspension. Resting and stressed subtracted simultaneous urethral pressure profilometry was performed immediately pre- and postcolposuspension in 26 bitches diagnosed with SMI. All of the urethral pressure profiles were measured in anaesthetized bitches using a standard technique and two orientations of the catheter transducers (dorsal and left). Readable pre- and postoperative urethral pressure profiles were obtained in 20 of the 26 bitches. Subjective and objective evaluation of the profiles showed significant differences in the profiles pre- and postcolposuspension. Immediately postoperatively there were significant ( P < .05) increases in functional profile length, maximum urethral closure pressure (MUCP), and distance between the bladder neck and the first negative respiratory peak and stressed spike. There was a significant ( P < .001) decrease in the percentage of negative spikes extending below the resting intravesical pressure on the subtracted profile. The pressure transmission profiles were significantly ( P < .001) altered by surgery. The findings presented support the hypothesis that colposuspension may restore continence by increasing pressure transmission to the proximal urethra and bladder neck. The results also suggest that immediately after surgery functional urethral length and urethral resistance are increased.     

Proximal Urethral Reconstruction Using a Distally Based Ventral Bladder Tube Flap An Experimental Study

Reconstruction of the proximal urethra using a distally based tube flap mobilized from the ventral bladder wall was performed on 12 clinically normal dogs after total prostatectomy and resection of 2 cm of membranous urethra. One dog was euthanized at 6 hours and one at 36 hours after surgery because of surgical complications. Five dogs were euthanized at 10 days, two dogs at 6 weeks and three dogs at 12 weeks. Advancement of the tube flap allowed for tension-free anastomosis to the membranous urethra. Vascular integrity was maintained in all flaps. Intermittent to continuous postoperative urinary incontinence occurred in 7 of 10 dogs. The incontinence was transient in all 6 and 12 week dogs except one in which a persistent stress incontinence developed. Mild to severe dysuria was noted in 8 of 10 dogs, but was also transient in all of the 6 and 12 week dogs, with the exception of one dog. Postoperative urethral closure pressure profilometry revealed decreased tone in the membranous urethra in all 6 and 12 week dogs. It was concluded that proximal urethral reconstruction, using a ventral bladder tube flap, is a viable technique that may permit functional urodynamic recovery in dogs with significant proximal urethral loss.     

A URINARY BLADDER FIBROSARCOMA IN A YOUNG DOG

A 14-month-old female dog, Gos d'Atura Catala was presented for a 7-month-history of reoccurring urinary tract infection. Using sonography, a focal multilobulated thickening of the urinary bladder wall was discovered. The solid mass was arising from the area of the ureteral papllDae and bulging into the lumen of the bladder neck. The wall of the urethra was uniformly thickened. These findings were not considered typical for a generalized urinary tract infection but more indicative of local severe inflammation, neoplasia or hyperplasia in the area of the ureteral openings. The thickening of the urethra was suggestive of urethritis or neoplastic infiltration. Signs of metastasis were not detected on the thoracic radiographs or in the remainder of the abdominal ultrasound examination. A surgical excision of the multilobulated mass was performed and histologic examination was conducted. A fibrosarcoma in the lamina propria of the urinary bladder wall was diagnosed. Because of reoccurence of hematuria and unresponsiveness to therapy the dog was euthanized. Postmortem examination confirmed the diagnosis of fiborsarcoma in the urinary bladder. Additionally, neoplastic infiltration of the urethral wall and metastasis in the lungs and liver were detected histopathologically.     

Simultaneous cystometry and uroflowmetry for evaluation of micturition in two dogs

A recently developed urodynamic testing procedure was used to evaluate disorders of micturition in 2 dogs. The procedure simultaneously recorded intravesical pressure and urine flow during micturition. In an 11-year-old spayed female Sheltie that could not urinate normally, a micturition study demonstrated functional outflow obstruction of the urinary bladder. Although the urethra was patent, the urethral resistance factor, as calculated from pressure and flow data, was extremely high during voiding efforts. A urethral transitional cell carcinoma along with secondary infection, inflammation, and fibrosis were found to be responsible for the dog's problem. Ability to urinate was restored following removal of the affected portion of the urethra. In a 6-year-old spayed female Doberman Pinscher with urinary incontinence during sleep, a micturition study demonstrated urethral incompetence. During infusion of 0.9% NaCl solution into the bladder, the fluid flowed through the urethra before the detrusor muscle contracted, and urethral resistance during voiding was low. The dog's incontinence was responsive to estrogen administration.     

Postpartum partial cystectomy through the vagina in a mare with everted partially necrotic bladder.

The bladder of a 750-kg Clydesdale mare had everted through the urethra into the vagina immediately after parturition. The bladder was reinverted into the peritoneal cavity by an attending veterinarian, but 4 days later, the bladder was everted again in the vagina. The mare was able to void urine through both ureters, which could be seen in the mucosal surface of the bladder. The everted bladder had become edematous and could not be reinverted through the urethra. A considerable portion of the fundus was necrotic. The mare was administered xylazine epidurally to induce perineal analgesia, and the necrotic portion of the bladder was resected and healthy bladder tissue was opposed with a double layer of simple continuous sutures. The urethral sphincter was longitudinally incised through the vaginal mucosa to allow reinversion of the bladder through the urethra. A purse-string suture inserted in the urethral opening decreased the urethral diameter and prevented recurrence of the condition. An inflated Foley catheter was maintained in the bladder for 5 days. The mare recovered normal urination after the catheter was removed.     

Is the Male Dog Comparable to Human? A Histological Study of the Muscle Systems of the Lower Urinary Tract

Because of their superficial anatomical resemblance, the male dog seems to be suitable for studying the physiologic and pathological alterations of the bladder neck of human males. The present study was carried out to compare and contrast the muscular anatomy of the male dog lower urinary tract with that of humans. The complete lower urinary tract, including the surrounding organs (bulb of penis, prostate, rectum and musculature of the pelvic floor) were removed from adult and newborn male dogs and histologically processed using serial section technique. Based on our own histological investigations, three-dimensional (3D)-models of the anatomy of the lower urinary tract were constructed to depict the corresponding structures and the differences between the species. The results of this study confirm that the lower urinary tract of the male dog bears some anatomical resemblance (musculus detrusor vesicae, prostate, prostatic and membranous urethra) to man. As with human males, the two parts of the musculus sphincter urethrae (glaber and transversostriatus) are evident in the canine bladder neck. Nevertheless, considerable differences in formation of individual muscles should be noted. In male dogs, no separate anatomic entity can be identified as vesical or internal sphincter. The individual course of the ventral and lateral longitudinal musculature and of the circularly arranged smooth musculature of the urethra is different to that of humans. Differences in the anatomy of individual muscles of the bladder neck in the male dog and man suggest that physiological interpretations of urethral functions obtained in one species cannot be attributed without qualification to the other.     

Ultrasonography of the urinary tract in 29 female Saanen goats

The left and right kidneys, ureters, urinary bladder and urethra of 29 female clinically healthy Saanen goats were examined via transcutaneous and transrectal ultrasonography. In order to establish reference values the examinations were performed using a 5.0 MHz linear transducer to scan the right caudal costal part of the abdominal wall, right and left dorsal flanks and right and left inguinal regions of standing goats. A 5.0 MHz intracavity probe was used for transrectal ultrasonographic examination of the urinary bladder and urethra. The kidneys were examined in longitudinal and cross section and assessed subjectively. They could usually be seen from the 12th intercostal space on the right side and dorsal right flank. The right kidney was 8.0 ± 0.67 cm long and the left was 8.4 ± 0.64 cm long. The ureters could not be visualized in any of the goats. The length of the urinary bladder was 5.1 ± 1.38 cm, and its largest cross-sectional diameter was 2.6 ± 1.01 cm. The urethra was seen in 23 goats and appeared as echogenic lines with no visible lumen. The transition from the neck of the bladder to the internal urethral orifice extended beyond the brim of the pelvis in only one goat.