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.     

Traumatic urethral avulsion at the preputial fornix in a cat

A cat with pelvic fractures from being hit by a car had voided no urine in 13 hours despite iv administration of fluids. Abdominal radiography had revealed the pelvic fractures and apparently intact urinary bladder. Urine did not flow from a urethral catheter, and contrast radiography revealed the catheter to be extra-urethral within the penis. Intravenous pyelography revealed intact ureters and urinary bladder; celiotomy confirmed intact urinary bladder. Cystotomy and normograde urethral catheterization allowed localization of the ruptured urethra within the deep subcutaneous tissues of the caudal portion of the abdomen. After closure of the cystotomy and celiotomy incisions, perineal urethrostomy was performed.     

Retrograde flow of spermatozoa into the urinary bladder of dogs during ejaculation or after sedation with xylazine

Retrograde flow of spermatozoa into the urinary bladder of dogs during ejaculation or after administration of xylazine was examined. In experiment 1, the mean (+/- SD) spermatozoal concentration in urine collected by cystocentesis before ejaculation was 0.322 +/- 0.645 X 10(6)/ml. After ejaculation, motile spermatozoa were present in the urine collected by cystocentesis from 12 of 15 dogs, and the concentration of spermatozoa in the urine (5.139 +/- 7.014 X 10(6)/ml) was higher (P less than 0.025) than the concentration in the urine collected before ejaculation. The percentage of the total number of spermatozoa that were displaced during ejaculation and flowed into the urinary bladder (retrograde flow) ranged from 0 to 99.75% (24.67 +/- 33.98%). In experiments 2 and 3, administration of xylazine to sexually rested dogs induced retrograde flow of spermatozoa into the urinary bladder. In experiment 2, all dogs had spermatozoa in urine collected after xylazine administration, with motile spermatozoa present in the urine from 9 of 10 dogs. In experiment 3, urine collected from dogs before administration of xylazine was azoospermic or contained few, nonmotile spermatozoa (0.063 +/- 0.135 X 10(6)/ml), whereas urine collected after administration of xylazine had more (P less than 0.025) and motile spermatozoa (3.717 +/- 4.273 X 10(6)/ml). In experiment 4, administration of xylazine to dogs after ejaculation did not increase the concentration of spermatozoa in the urine. Results indicate that spermatozoa flow into the urinary bladder of dogs during ejaculation or after administration of xylazine to sexually rested dogs.     

Successful treatment of Corynebacterium urealyticum encrusting cystitis with systemic and intravesical antimicrobial therapy

A 6-year-old Saint Bernard dog was diagnosed with encrusting cystitis caused by Corynebacterium urealyticum. The infection persisted despite the prolonged use of antimicrobials and surgical debridement of the urinary bladder. Resolution occurred following intravenous vancomycin, urine acidification, and intravesical gentamicin. The challenges involved in the treatment of encrusting cystitis are described.     

IMAGING DIAGNOSIS—URINARY BLADDER DUPLICATION IN A CAT

A female kitten presented for chronic, intermittent, antibiotic‐responsive urinary incontinence and chronic kidney disease. Abdominal ultrasound identified bilateral pelvic/ureteral dilation and three closely apposed thin‐walled fluid‐filled structures in the caudal abdomen, extending toward the pelvic inlet. Excretory urography and negative contrast cystography identified contrast medium accumulation from the dilated ureters into two tubular soft tissue masses of the caudal abdomen, with subsequent gradual filling of a more cranially located urinary bladder. A retrograde vaginocystourethrogram identified a normal uterus, normal vagina, and a single urethra continuous with the cranially located urinary bladder. Antemortem diagnosis was suspicious for bilateral ectopic ureteroceles. Postmortem diagnosis, 35 months following initial presentation, determined the fluid‐filled masses to have abundant smooth muscle in the wall, including a muscularis mucosa connected by a common ostium, consistent with urinary bladder duplication. Urinary bladder duplication should be included as a differential diagnosis in cats with these clinical and imaging characteristics. In this case, differentiation of ectopic ureterocele from urinary bladder duplication required histological confirmation.     

Contrast‐enhanced voiding urosonography: A new,radiation‐free,alternative method for imaging of urinary bladder and urethra in healthy dogs

Contrast‐enhanced voiding urosonography (CE‐VUS) has been generally considered as a promising tool to diagnose vesicoureteral reflux and abnormalities in lower urinary tract in human patients, especially in children. The purpose of this prospective study is to evaluate the quality of images of the urinary bladder and urethra obtained by CE‐VUS using a second‐generation ultrasound contrast agent (SonoVue®) in healthy dogs and to investigate the safety profile of SonoVue® after intravesical administration. Eighty‐four CE‐VUS examinations with SonoVue® were successfully performed in both unsedated (39/84) and sedated (45/84) dogs. Contrast‐enhanced voiding urosonography examination of urinary bladder was technically successful in all (84/84) dogs. The image quality was not considered adequate in five (5/84) dogs including three dogs in whom layering of contrast media during filling phase was observed and two dogs with premature destruction of microbubbles. In these five dogs, the problem was readily recognized and corrected such that the procedure was still successfully undertaken. The assessment of the urethra during spontaneous micturition was successfully performed in all (84/84) dogs in whom voiding was elicited during the examination. No side effects were observed after intravesical application of SonoVue®. This study demonstrates that CE‐VUS is a feasible and valuable technique to evaluate low urinary tract morphology and function in dogs. Based on our review of the literature, there are no published reports about the use of this method in dogs.     

LYMPHOMA AFFECTING THE URINARY BLADDER IN THREE DOGS AND A CAT

Three dogs and one cat with lymphoma affecting the urinary bladder are reported and the findings on abdominal radiographs and ultrasound are described. Mural lesions representing lymphoma affecting the urinary bladder were identified ultrasonographically in all animals. The most common complications associated with urinary bladder lymphoma were hydronephrosis and hydroureter. In two patients contrast radiography was necessary to detect leakage of urine in the peritoneal and retroperitoneal space. The radiographic and ultrasonographic signs were similar to those reported with other urinary bladder neoplasms; hence urinary bladder lymphoma could not be distinguished from the more common urinary bladder neoplasms, such as transitional cell carcinoma. It is important to include lymphoma in the differential diagnosis of urinary bladder wall thickening and mural mass in dogs and cats.     

Application of the 51Cr-EDTA urinary recovery test for assessment of intestinal permeability in the horse

Altered intestinal permeability is implicated in the pathogenesis of diverse equine medical conditions including alimentary laminitis and protein-losing enteropathies associated with parasitic infection. The aims of this study were to assess the feasibility of applying the 51Cr-EDTA absorption test for the assessment of intestinal permeability in the horse, and to apply this test in horses with experimentally induced alterations in gastrointestinal function. Four healthy ponies were administered 36 MBq of 51Cr-EDTA via naso-gastric tube, and urine samples were collected into polythene bags strapped to the pony's abdomen. Total urine voided every 6 h was collected during each test, and 1 ml samples were taken for measurement of gamma-radiation. Urinary recovery of 51Cr-EDTA was measured following intravenous atropine sulphate or bethanecol, and following 22 and 46 days of administration of 250,000 third-stage cyathostome larvae. There was no significant difference in urinary 51Cr-EDTA recovery following the control treatment, and following atropine or bethanecol administration, but significant increases were detected in the animals with experimental cyathostome infection consistent with increased permeability of the intestinal membrane. Motility modifying agents (bethanecol and atropine) did not affect absorption of 51Cr-EDTA, suggesting that subtle changes in motility might not affect the ability of this test to detect altered intestinal permeability. The finding of increased urinary recovery of 51Cr-EDTA in ponies with cyathostome infection suggests that 51Cr-EDTA may be a useful marker for assessment of intestinal permeability in the horse.     

Transitional cell carcinoma of the urinary bladder in a 14-year-old dog

A 14-year-old spayed female poodle-pekinese dog with a history of hematuria was tentatively diagnosed with non-radiopaque uroliths or urinary bladder neoplasia following temporary resolution of clinical signs after several rounds of antibiotic treatments, normal abdominal radiographs and no growth on urine culture. Abdominal ultrasound revealed a mass in the trigone area of the urinary bladder which was confirmed to be an invasive transitional cell carcinoma by histopathology following euthanasia.     

Xylazine does not induce retrograde flow of spermatozoa into the urinary bladder of sexually rested boars

The effect of xylazine on the retrograde flow of spermatozoa from their storage sites in the epididymides and vasa deferentia into the urinary bladder of sexually rested boars was examined. The bladder of four boars was evacuated through a surgically implanted urinary catheter and the urine was examined for the presence of spermatozoa. Boars were then given an injection of 2.2 mg of xylazine per kilogram of body weight and, immediately thereafter, 500 ml of saline was infused into the urinary bladder. Approximately 50 ml of the post-treatment mixture of urine and saline, referred to as 'urine', was collected through the catheter at 5, 10, 15, 20, 30 and 45 min after the injection of xylazine, and examined immediately for the presence and motility of spermatozoa. At 60 min, the urinary bladder was evacuated and the remaining 'urine' was examined for the presence and motility of spermatozoa. None of the pre-xylazine urine and post-xylazine fractions of 'urine' had motile spermatozoa and xylazine did not increase (P > 0.1) the concentration and the number of spermatozoa in the post-treatment 'urine'. Thus, in contrast to other species, xylazine does not induce retrograde flow of spermatozoa into the urinary bladder of boars.     

The pharmacokinetics and pharmacodynamics of furosemide in anesthetized dogs with normal and experimentally decreased renal function

The pharmacokinetics and the biliary and urinary excretions following intravenous administration of furosemide (5 mg/kg) were investigated in the anesthetized dogs with normal and experimentally reduced renal function. After the administration, furosemide caused diuretic and choleretic response, and was excreted into urine and bile at almost similar rate to plasma concentration decay in normal dogs. Half maximum diuretic response was obtained at 1.5 micrograms/ml of plasma concentration and 100 micrograms/min of urinary excretion rate of furosemide. Acute renal failure was produced in dogs by the intravenous administration of mercuric chloride (HgCl2, 2 mg/kg). In HgCl2-treated dogs, the prolongation of half life (T1/2 beta) and the decrease in plasma clearance were noted with the decreased diuretic response. These changes in parameters appeared to be associated with the decrease in excretion of furosemide into the urine, but not into the bile. Plasma level-diuretic response relationship was extensively shifted to the right in HgCl2-treated dogs, while urinary dose-response relationship did not change significantly between two groups. These results suggest that the decreased response to furosemide in HgCl2-treated dogs seems to be due to the decreased renal clearance rather than to the subsensitivity to furosemide on the site of action.     

Effect of diuresis on urinary excretion and creatinine clearance in the horse

Endogenous creatinine clearance and renal excretion of phenylbutazone, osmotically active material, and compounds contributing to the urinary refractive index were studied in 12 Thoroughbred mares after no treatment, after water administration, or after furosemide administration. Urine was quantitatively collected, using urinary bladder catheters. On average, urine flow of the mares was 9 microliters/min/kg without treatment and increased to about 50 microliters/min/kg after water administration and to about 70 microliters/min/kg after furosemide administration. Water administration increased creatinine clearance values and excretion of phenylbutazone. Furosemide administration increased urinary excretion of osmotically active compounds and compounds contributing to urinary refractive index and decreased excretion of phenylbutazone.     

Canine Vesicourachal Diverticula

Nine cases of canine vesicourachal diverticula associated with symptoms of lower urinary tract infection were evaluated. Proteus sp urinary tract infection was identified in 6 of 7 cases in which urine cultures were performed. A diverticulum was demonstrated in all cases by contrast urocystography. Surgical excision of the diverticula followed by administration of antimicrobial agents for an appropriate period usually produced eradication of clinical symptoms. Resolution of recurrent urinary tract infection following excision of the urachal diverticula would indicate that these anomalous structures are a predisposing cause of bacterial infection of the urinary tract.     

Endoscopic diagnosis of unilateral ectopic ureter in a yearling filly

Unilateral ectopic ureter was diagnosed by endoscopic examination in an 18-month-old filly examined because of chronic urine dribbling. Intramuscular administration of azosulfamide discolored the urine and enhanced visualization of the ectopic ureter. Endoscopy proved valuable in determining that only one ureter entered the urinary bladder and in locating the ectopic ureter in the ventral portion of the vagina.     

INTRAARTERIAL INJECTION OF IODINATED CONTRAST MEDIUM FOR CONTRAST ENHANCED COMPUTED TOMOGRAPHY OF THE EQUINE HEAD

Minimizing the volume of contrast administered for contrast‐enhanced computed tomography (CT) of the equine head is desirable for reducing costs and risks of adverse reactions, however evidence‐based studies on the effects of varying volumes on image quality are currently lacking. The objective of the current study was to determine whether low‐volume intraarterial administration of contrast medium would result in an equivalent image quality and tissue attenuation vs. high‐volume intravenous bolus administration. A prospective cross‐over experimental design was used in a sample of six horses. After anesthetic induction, the right carotid artery was exposed surgically and catheterized. Four CT scans of the cranium were performed for each horse: baseline, immediately following intraarterial contrast injection, five‐min postinjection (return to baseline) and a final scan after intravenous contrast administration. Soft tissue attenuation in predetermined regions of interest (ROI); and length, width, and height measurements of the pituitary gland were recorded at each time point. Horses were euthanized and measurements of the pituitary gland were repeated postmortem. No adverse reactions to contrast administration were observed. Intraarterial and intravenous administration of contrast medium resulted in significantly greater soft tissue enhancement of some brain ROI's and the pituitary gland vs. baseline values. Pituitary gland measurements made on postcontrast CT images did not differ from those obtained during postmortem examination. Findings indicated that low‐dose intraarterial administration of contrast material in the equine head resulted in comparable soft tissue enhancement vs. high volume intravenous administration.     

Pelvic bladder in dogs without urinary incontinence

Double-contrast cystography was performed simultaneously with cystometrography in 6 male and 6 female dogs. All dogs were continent, and results of urinalyses were normal. Initial radiographs were made following intravesical infusion of 0.88 ml of positive contrast medium/kg of body weight. Additional radiographs were made during infusion of CO2. The last radiographs were made at the time of detrusor reflex (11 dogs) or when intravesical pressure reached 50 cm H2O (1 female). An average of 34% (range, 11% to 67%) of bladder length was within the pelvic canal when only the positive contrast medium was infused into the bladders. By the end of CO2 infusion, the bladder neck was more cranially located in 5 of 6 males and in 5 of 6 females. On the last radiographs made, an average of 19% (range, 10% to 35%) of bladder length was within the pelvic canal in 3 of 6 males and in 4 of 6 females. The bladder neck was rounded in 10 of 12 dogs. Thus, it was concluded that previous reports associating pelvic urinary bladder with urinary incontinence and other urologic abnormalities are questionable.     

CONTRAST RADIOGRAPHY OF THE LOWER URINARY TRACT IN THE MANAGEMENT OF OBSRUCTIVE UROLITHIASIS IN SMALL RUMINANTS AND SWINE

Contrast radiographic visualization of the small ruminant and porcine lower urinary tract is an infrequently used modality for the evaluation and management of obstructive urolithiasis. The administration of contrast medium through a tube cystostomy catheter used to divert urine flow until the resolution of the obstruction may provide an easy method to evaluate the status of the urethral obstruction. Contrast fluoroscopy is utilized to monitor and visualize therapeutic flushing of the urethra. A review of 26 patients seen at the Veterinary Medical Teaching Hospital suggested that among the radiographic techniques used, positive contrast normograde cystourethrography through the tube cystostomy catheter allowed the best visualization of the lower urinary tract structures and enabled assessment of the resolution of the obstructive lesion.     

Pharmacokinetics and renal clearance of oxytetracycline after intravenous and intramuscular administration to dairy cows

Following intravenous administration of an oxytetracycline-HC1 and an oxytetracycline-dihydrate formulation to dairy cows, no statistical difference could be found between the pharmacokinetic parameters, derived from the three-compartment model, of these preparations. Urinary recovery was continued for a period of 72 h following intravenous or intramuscular OTC administration. The recovery of OTC in the urine in the 72-h period was in the range of 73% to 96% of the available dose administered. The renal OTC clearance, the renal creatinine clearance, the urinary flow, and the interrelationships of these were determined on the basis of urine and plasma data. The mean OTC renal clearance ranged from 482 to 1050 ml/min and the creatinine clearance from 651 to 1304 ml/min. The OTC and creatinine clearances were significantly correlated to the urine flow up to 30 ml/min. The total body clearance and renal clearance values were of the same order of magnitude, and along with the urine recovery data they provided evidence of predominantly renal route of OTC elimination in dairy cows. The renal OTC elimination is the net result of mainly glomerular filtration, partly tubular secretion, minus reabsorption in the urogenital tract.     

Pharmacokinetics of procaterol in thoroughbred horses

Procaterol (PCR) is a beta‐2‐adrenergic bronchodilator widely used in Japanese racehorses for treating lower respiratory disease. The pharmacokinetics of PCR following single intravenous (0.5 μg/kg) and oral (2.0 μg/kg) administrations were investigated in six thoroughbred horses. Plasma and urine concentrations of PCR were measured using liquid chromatography–mass spectrometry. Plasma PCR concentration following intravenous administration showed a biphasic elimination pattern. The systemic clearance was 0.47 ± 0.16 L/h/kg, the steady‐state volume of the distribution was 1.21 ± 0.23 L/kg, and the elimination half‐life was 2.85 ± 1.35 h. Heart rate rapidly increased after intravenous administration and gradually decreased thereafter. A strong correlation between heart rate and plasma concentration of PCR was observed. Plasma concentrations of PCR after oral administration were not quantifiable in all horses. Urine concentrations of PCR following intravenous and oral administrations were quantified in all horses until 32 h after administration. Urine PCR concentrations were not significantly different on and after 24 h between intravenous and oral administrations. These results suggest that the bioavailability of orally administrated PCR in horses is very poor, and the drug was eliminated from the body slowly based on urinary concentrations. This report is the first study to demonstrate the pharmacokinetic character of PCR in thoroughbred horses.     

Corynebacterium urealyticum urinary tract infection in dogs and cats: 7 cases (1996-2003)

OBJECTIVE: To identify clinical features of Corynebacterium urealyticum urinary tract infection in dogs and cats and antimicrobial susceptibility patterns of C urealyticum isolates. DESIGN: Retrospective study. ANIMALS: 5 dogs and 2 cats. PROCEDURE: Medical records of dogs and cats for which C urealyticum was isolated from urine samples were reviewed. Isolates from clinical cases, along with previously lyophilized unsubtyped isolates of Corynebacterium spp collected between 1977 and 1995, were examined and, if subtyped as C urealyticum, tested for antimicrobial susceptibility. RESULTS: Signalment of infected animals was variable. Prior micturition disorders were common, and all animals had signs of lower urinary tract disease at the time C urealyticum infection was diagnosed. Median urine pH was 8.0; WBCs and bacteria were variably seen in urine sediment. In vitro antimicrobial susceptibility testing of 14 C urealyticum isolates revealed that all were susceptible or had intermediate susceptibility to chloramphenicol, tetracycline, and vancomycin and most were susceptible to enrofloxacin. Thickening of the bladder wall and accumulation of sediment were common ultrasonographic findings. Contrast radiography or cystoscopy revealed findings consistent with encrusting cystitis in 3 dogs. Infection resolved in 2 dogs following surgical debridement of bladder plaques and antimicrobial administration. In 2 other dogs and 1 cat treated with antimicrobials, infection with C urealyticum resolved, but urinary tract infection with a different bacterial species developed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that preexisting urinary tract disorders are common in dogs and cats with C urealyticum infection. Treatment with appropriate antimicrobials in combination with surgical debridement might eliminate C urealyticum infection.