Surgical management of a ureteral defect with ureterorrhaphy and of ureteritis with ureteroneocystostomy in a foal

A 2-day-old male foal developed uroperitoneum. Initial exploration of the abdomen via ventral midline celiotomy failed to localize the source of uroperitoneum. Bilateral nephropyelocentesis and antegrade urography were performed, and a defect in the right ureter and stenosis of the left ureter were identified. With the foal in dorsal recumbency in the Trendelenburg position, ureterorrhaphy was performed on the right ureter. After ureterorrhaphy, a ureteral catheter was maintained as a stent. The stenotic left ureter was transected, and ureteroneocystostomy was performed using a drop-in mucosal apposition technique. The ureteral catheter was removed 26 days after surgery. Histopathologic findings suggested that ureteritis of unknown origin was a possible initiating factor for stenosis of the left ureter. The drop-in technique for ureteroneocystostomy may be used successfully for ureteral transposition in horses. Ureterorrhaphy combined with the use of a ureteral stent may be used to repair ureteral defects in foals.     

URETERAL DUPLICATION IN A DOG

A male neutered dog of unknown age had recurrent urinary tract infection and caudal abdominal pain. Using sonography, large dilated tubular structure filled with echogenic fluid was seen extending from the left kidney to the level of the bladder neck. In an excretory urogram there was left hydronephrosis with a normal ureter. Computed tomographic evaluation of the abdomen confirmed a large tubular structure extending from the kidney with a blind ending caudally. The left kidney, ureter, and associated tubular structure were surgically removed. No connection was found between the tubular structure and the ureter. Gross evaluation and histopathologic evaluation confirmed the tubular structure to be a ureter, consistent with a diagnosis of ureteral duplication.     

Digital fluoroscopic excretory urography, digital fluoroscopic urethrography, helical computed tomography, and cystoscopy in 24 dogs with suspected ureteral ectopia

The purpose of this study was to determine the diagnostic utility of helical computed tomography (CT) for the diagnosis of ectopic ureters in the dog and to compare these findings with those of digital fluoroscopic excretory urography and digital fluoroscopic urethrography. Ureteral ectopia was confirmed or disproved based on findings from cystoscopy and exploratory surgery or postmortem examination. Of 24 dogs (20 female, 4 male) evaluated, 17 had ureteral ectopia. Digital fluoroscopic excretory urography and CT correctly identified ureteral ectopic status and site of ureteral ectopia (P < .05). Urethrography did not reliably detect ureteral ectopia. No false-positive diagnoses of ureteral ectopia were made in any of the imaging studies. Cystoscopic findings significantly agreed with findings during surgery in determining ureteral ectopic status and ectopic ureter site. One false-positive cystoscopic diagnosis of unilateral ureteral ectopia was made in a male dog. Kappa statistics showed better agreement between CT and both cystoscopy and surgical or postmortem examination findings with regard to presence and site of ureteral ectopia compared with other imaging techniques. CT was more useful than other established diagnostic imaging techniques for diagnosing canine ureteral ectopia.     

Proximal ureteral ectopia causing hydronephrosis in a kitten

A 2-month-old, female cat was presented for abdomen dilation. The patient was undernourished, and severe left hydronephrosis was diagnosed after clinical, ultrasonographical and radiographical examination. Although pyelography was performed in order to visualise the ureteral course, surgery was necessary to reach a final aetiological diagnosis and treatment. At gross examination, the left ureter crossed the renal capsula at the level of the caudal renal pole, and the subcapsular ureteral segment was markedly dilated. Distal to the renal capsula, the left ureter was very thin when compared to the right. The parenchyma of the left kidney, as suggested by ultrasonographical evaluation, was extremely reduced in thickness. An ureteronephrectomy was performed. Histopathological evaluation revealed glomerular sclerosis and diffuse parenchymal fibrosis. Severe hydronephrosis derived from an altered renal pelvic anatomy and abnormal ureteral course determining functional stenosis. Diagnosis of congenital anomaly before development of complications such as hydronephrosis could have allowed a surgical renal capsulectomy and obstruction relief. To the author's knowledge, this is the first report of severe hydronephrosis associated to altered renal pelvic anatomy and proximal ureteral ectopia in cat.     

CALCIUM OXALATE URETEROLITH IN A CAT

A 4-year-old cat was presented for polyuria and polydipsia. Unilateral hydronephorosis and hydroureter was diagnosed on ultrasound examination of the abdomen, and right ureteral calculi were seen in survey abdominal radiographs. Intravenous urography confirmed hydronephrosis and indicated poor renal funttion in the right kidney. Surgical removal of the ureteral calculus improved right renal function. Analysis of the calculus indicated composition of calcium oxalate, an uncommon calculus in cats.     

MULTIDETECTOR‐ROW COMPUTED TOMOGRAPHIC CHARACTERISTICS OF PRESUMED PREURETERAL VENA CAVA IN CATS

Preureteral vena cava (circumcaval ureter, retrocaval ureter) occurs in a third of the feline population and has been associated with ureteral strictures in humans. The aim of this retrospective cross‐sectional study was to describe the contrast‐enhanced multidetector row computed tomographic (MDCT) characteristics of presumed preureteral vena cava in a group of cats. Medical records from two institutions located in different continents were searched from 2010–2013 for cases with complete contrast‐enhanced MDCT examinations of the abdomen (i.e. included the entire course of the ureters and prerenal and renal segments of the caudal vena cava) and a diagnosis of preureteral caudal vena cava. For cases meeting inclusion criteria, CT scan data were retrieved and characteristics of the preureteral caudal vena cava were recorded. Presence of concomitant renal or ureteral diseases was also recorded. A total of 272 cats had contrast‐enhanced abdominal CT scans during the study period and of these, 68 cats (22.43 ± 4.96%) had a diagnosis of presumed preureteral vena cava. In all affected cats, a “reverse‐J ureter” was observed, i.e. a ureter running medially at the level of L4–5, passing dorsally to the caudal vena cava and then exiting ventrally between the caudal vena cava and aorta returning to its normal position. Having a preureteral vena cava resulted in an increased risk for concurrent urinary signs (OR = 3.00; CI: 95%; 1.28–6.99; P = 0.01). Findings supported the use of contrast‐enhanced MDCT for characterizing morphology of preureteral vena cava and its relation with ureters in cats.     

Sonographic diagnosis of a presumed ureteral tear in a horse

A 14-year-old thoroughbred gelding was presented for the evaluation of acute abdominal pain. Rectally, there was a soft fluctuant painful swelling dorsal to the bladder and to the right of the midline. The creatinine concentration of the peritoneal fluid was 15 mg/dl. Transrectal ultrasonographic examination of the urinary tract revealed a large collection of fluid dissecting from the pelvic portion of the right ureter ventrally through the right side of the bladder wall and into the retroperitoneal space, and a thickened right ureter and bladder wall at the level of the trigone. Cystoscopically there was moderate hemorrhage within the wall of the bladder. Ultrasonography revealed air within the retroperitoneal fluid collection after ureteral catheterization, confirming the preliminary diagnosis of a tear in the right ureter. The gelding was treated medically. After 48 h of hospitalization, nuclear scintigraphy revealed normal clearance from both kidneys and no apparent leakage from the right ureter. The ureteral tear and urinoma were monitored using transrectal ultrasound until resolution. The horse was successfully returned to racing. This case establishes the value of diagngstic ultrasound in the diagnosis and monitoring of a traumatic ureteral tear in a horse.     

Circumcaval ureter in two ferrets

BackgroundCircumcaval ureter is an anomaly in the development of the caudal vena cava, rarely reported in ferrets.Materials and methodsInclusion criteria for ferrets were circumcaval ureter confirmed on surgery or post-mortem examination. Data collection of ferrets with circumcaval ureters presented between January 2014 and January 2021 included signalment, medical history, clinical signs, laboratory diagnostics, diagnostic imaging results, treatments, and clinical outcomes.ResultsTwo ferrets met the inclusion criteria. One presented following diarrhea, and one was found on routine examination that revealed a right nephromegaly. Abdominal ultrasound revealed severe unilateral hydronephrosis associated with hydroureter in both ferrets. No obvious cause of obstruction was identified. Biochemical results were unremarkable in both patients. Hydronephrosis was investigated through CT scans, revealing Type 1 circumcaval ureter in both ferrets. Section and relocation of the right ureter by uretero-vesical anastomosis was performed in one ferret. This ferret died 48 hours later following a nephrectomy performed due to persistent hydronephrosis. The second cas underwent right nephrectomy andd ureter resection due to severe hydronephrosis and stenosis of the circuncaval segment. This ferret has remained healthy on followup with no abnormalities found in biochemistries or ultrasound examination.Conclusion and case relevanceFindings suggest that circumcaval ureter should be suspected in ferrets with unilateral hydronephrosis and associated hydroureter without any identified cause of obstruction on abdominal ultrasonography. It should be confirmed with CT scan and/or urography and treated surgically.     

ULTRASONOGRAPHIC DETECTION OF ADRENAL GLAND TUMOR AND URETEROLITHIASIS IN A GUINEA PIG

A 5-year-old guinea pig was presented to the University of Berne Small Animal Radiology Department for an ultrasound examination of the abdomen to confirm a suspected diagnosis of Cushing's syndrome. The patient had bilateral alopecia, was apathic and obese. Ultrasonographically, a tumor of the left adrenal gland, obstruction of the left ureter by an ureterolith, as well as hydronephrosis of the left kidney were detected. During surgery to relieve the ureteral obstruction the adrenal gland tumor was removed. The guinea pig died post-operatively due to blood loss. The left adrenal gland tumor was found histopathologically to be an adenoma and the right adrenal gland also had multiple small adenomas, but grossly appeared normal. The ureterolith was analyzed and found by x-ray diffraction to consist of calcium carbonate.     

Radiographic techniques and interpretation of the acute abdomen

Radiography is a familiar and available imaging modality for the evaluation of patients with acute abdominal distress. Potential causes for acute abdominal distress include the hepatobiliary system, spleen, urogenital tract, and gastrointestinal tract. Radiographic signs associated with specific conditions are described, including gastric-dilation volvulus, urinary bladder rupture, ureteral rupture, urethral rupture, pancreatitis, and small intestinal obstruction. Additionally, contrast procedures that can be beneficial in evaluating the patient with acute abdomen, including positive contrast cystography, urethrography, excretory urography, and peritoneography, are described.     

Nephroliths and ureteroliths: a new stone age

Nephroliths may obstruct the renal pelvis or ureter, predispose to pyelonephritis, or result in compressive injury of the renal parenchyma leading to progressive chronic kidney disease. Indications for removal of nephroliths in dogs include obstruction, recurrent infection, progressive nephrolith enlargement, presence of clinical signs (renal pain), and patients with nephroliths in a solitary functional kidney. The most common indication for removal of upper tract uroliths in cats is ureteral obstruction caused by ureteroliths. Nonobstructive nephroliths in cats are not usually treated unless they move into the ureter resulting in ureteral obstruction.

The treatment approach to nephroliths and ureteroliths is different for dogs versus cats. Surgical removal of nephroliths or ureteroliths by nephrotomy and ureterotomy respectively is associated with potential for complications in more than 30% of cats treated by ureterotomy; therefore, minimally invasive options should also be considered. Extracorporeal shock wave lithotripsy (ESWL) treatment of nephroliths results in small “passable” stone fragments in most dogs, whereas ESWL does not work effectively in cats. Ureteral stents are effective for relief of ureteral obstruction by ureteroliths in both dogs and cats. Ureteral stents may be left in place long-term to relieve ureteral obstruction by ureteroliths. Post-operative morbidity and mortality are substantially lower for ureteral stent placement compared to open surgical ureterotomy in cats.     

URETEROLITHIASIS AND PAPILLOMA FORMATION IN THE URETER OF A GUINEA PIG

A 5-year-old guinea pig with suspected urolithiasis was presented for radiology and ultrasound examinations of the abdomen. Radiographically, an irregular-shaped mineral opacity was detected in the area of the urinary bladder. Ultrasonographically, pyelectasia of the right kidney, hydroureter with an ureterolith cranial to a thickened ureter wall close to the ureterovesical junction, and a thickened urinary bladder wall were detected. Histopathologically, the thickened ureter wall was found to be a papilloma. The ureter calculus consisted of 100% calcite.     

Ureteral obstruction and hydronephrosis in a cat associated with retroperitoneal infarction

A 9-month-old cat was presented for routine vaccination before rehoming. Physical examination revealed a palpable mass in the cranial abdomen. The right kidney was severely enlarged (6cmx4cm) on plain abdominal radiographs, and failed to opacify normally during intravenous urography. Ultrasonography demonstrated a hydronephrotic right kidney. During exploratory coeliotomy, a retroperitoneal mass was identified, adherent to the caudal edge of the right kidney, enveloping the ureter and blocking urine outflow. The ureter caudal to the mass was of normal size. Right ureteronephrectomy was performed; the mass was subsequently freed from adhesions to the caudal vena cava and sublumbar muscles and excised. Histopathological examination revealed the mass to be composed of both normal and necrotic adipose tissue and fibrous tissue surrounding the ureter and a thrombosed, recanalised vessel. This appearance was consistent with an area of infarction and fibrosis with obstruction of the ureter. The cat was clinically well 3 months postoperatively.     

Treatment of ureteral calculus obstruction with laser lithotripsy in an Atlantic bottlenose dolphin (Tursiops truncatus)

An adult female bottlenose dolphin (Tursiops truncatus) presented with acute anorexia secondary to progressive azotemia (blood urea nitrogen = 213 mg/dl, creatinine [Cr] = 9.5 mg/dl) and electrolyte abnormalities (K = 7.4 mEq/L). It was later diagnosed with postrenal obstruction secondary to bilaterally obstructing ureteral calculi seen on ultrasound. Treatment of the obstruction required two endoscopic procedures, cystoscopy for ureteral stent placement and ureteroscopy to perform intracorporeal lithotripsy on the obstructing calculi. Before the first procedure, the dolphin's azotemia was stabilized with aggressive fluid therapy, peritoneal dialysis, and treatment for acidosis. Diuresis subsequent to the fluid therapy enabled passage of the right obstructing urolith. For both endoscopic procedures, the dolphin was placed in left lateral recumbency due to the peritoneal dialysis catheter in the right retroperitoneal region. For the first procedure, a 12-French (Fr) flexible cystoscope was inserted retrograde into the bladder via the urethra, whereupon a calculus was seen obstructing the left ureteral orifice. A 4.8-Fr, 26-cm double-pigtail ureteral stent was placed up the left ureter to relieve the postrenal obstruction. Inadvertent proximal migration of the left ureteral stent occurred during the procedure. However, renal parameters (serum Cr = 5.8, K = 5.4) improved significantly by the next day. For the second procedure, 28 hr later, ureteroscopy was performed to treat the calculus and replace the existing stent with a longer stent. The left ureteral calculus was pulverized into tiny fragments by using a holmium:yttrium-aluminum-garnet laser inserted through a 6.9-Fr semirigid ureteroscope. The migrated stent was visualized in the distal left ureter and replaced with a 90-cm single-pigtail ureteral stent that was sutured exterior to the urogenital slit and removed 3 days later. Renal function normalized over the next several days, and the dolphin recovered over the next 2 mo.     

EVALUATION OF THE URETER AND URETEROVESICULAR JUNCTION USING HELICAL COMPUTED TOMOGRAPHIC EXCRETORY UROGRAPHY IN HEALTHY DOGS

Abdominal computed tomography (CT) using a protocol designed for evaluation of the ureters was performed on six normal purpose-bred research dogs. After noncontrast CT, a postcontrast scan was performed 3 min post midpoint of injection of 400 mgI/kg body weight of diatrizoate meglumine/sodium. Ureteral and ureterovesicular junction anatomy were readily assessed with minimal patient preparation. The ureters were similar in size to reported values and the renal pelvis, ureter, and ureterovesicular junction were easily identified on both noncontrast and contrast-enhanced scans. There was a significant relationship between bladder volume and interureterovesicular junction distance but not between bladder volume and ureterovesicular junction to internal urethral orifice distance. A reliable bony landmark for the identification of the internal urethral orifice could not be determined. The results of this preliminary study of normal anatomy should facilitate the clinical use of CT in the evaluation of ureteral disease (e.g., ureteral ectopia).     

EXCRETORY UROGRAPHY AND ULTRASONOGRAPHY IN THE DIAGNOSIS OF BILATERAL ECTOPIC URETERS IN A FOAL

A 7-week-old Appaloosa filly was admitted for persistent urinary incontinence since birth. Vaginal speculum examination revealed urine flowing from an opening in the right vaginal wall. Cystoscopy demonstrated that the ureters did not terminate at the bladder. The endoscope passed easily from the vagina directly into a dilated right ureter. An excretory urogram confirmed the vaginal termination of at least one ureter, based upon extensive filling of the vagina with contrast media in the absence of bladder filling. Bilateral hydroureter and dilated renal pelves were demonstrated both by excretory urography and by ultrasonography. Euthanasia was requested by the owner in lieu of attempted surgical correction. At necropsy, it was confirmed that the right ureter entered the vagina and the left ureter terminated at the urethra. The diagnosis of bilateral ectopic ureter in this foal was suggested by the history and clinical signs, supported by endoscopy and ultrasonography, and confirmed by excretory urography and necropsy. This case establishes the value of diagnostic imaging techniques in the antemortem diagnosis of ectopic ureter.     

Correction of bilateral ureteral defects in a foal

Bilateral ureteral defects were diagnosed as the cause of depression and azotemia in an 8-day-old Thoroughbred filly. The azotemia resulted from accumulation of urine in the retroperitoneal area. A ventral midline laparotomy was performed, and defects found in both the left and right ureter were repaired. Uroperitoneum and abdominal distention, presumably from urine leakage at the left ureteral surgery site, were detected on the fourth postoperative day and necessitated abdominal drainage. Thirty-six hours later, the leakage stopped spontaneously, and the foal recovered normally. This report should help to differentiate ureteral defects in foals from the more common syndrome of ruptured bladder.     

Semen-Matrix Calculi in a Juvenile Chinchilla (Chinchilla lanigera)

A 10-month-old, intact male chinchilla (Chinchilla lanigera) was diagnosed with urolithiasis, unilateral hydroureter, and hydronephrosis secondary to ureteral obstruction confirmed by radiography and ultrasonography. Nephrectomy and cystotomy were performed, and the urolith was suspected to be a semen-matrix calculus (mineralized copulatory plug) based on the discovery of sperm within the renal pelvis of the nephrectomized kidney on histopathology; this was later confirmed through a postmortem examination. Three months after initial presentation the chinchilla was diagnosed with recurrent urolithiasis, hydroureter, and hydronephrosis of the remaining kidney and ureter, and euthanized due to poor prognosis. Necropsy confirmed the presence of semen-matrix calculi in the ureter and urinary bladder. Veterinary clinicians should consider semen-matrix calculi as a differential diagnosis for radiopaque calculi within the bladder or urethra of male chinchillas. Pathogenesis may be formation of a coagulum secondary to retrograde ejaculation.     

Hematuria caused by abdominal abscessation in a foal

A 4.5-month-old Standard-bred filly was referred for evaluation of pigmenturia. Initially, the pigmenturia had resolved with the administration of antibiotics, only to recur after their withdrawal. A dark red urine sample contained numerous RBC, WBC, and gram-negative rods (Escherichia coli). Ultrasonography revealed the right kidney to be large, with multiple cystic structures and a dilated renal pelvis and calices. Cystoscopy revealed a large blood clot within the bladder and urine coming from the left ureteral opening. Urine was not observed coming from the right ureter. It was suspected that the primary infection within the urinary tract was coming from the right kidney, with secondary ureteral obstruction and cystitis. Trimethoprim-sulfamethoxazole treatment was initiated. However, acute depression and abdominal pain developed several days later, and the foal died before assistance could be provided. Necropsy revealed a large abscess that had eroded into the right ureter and aorta and had ruptured, resulting in acute blood loss and death. The location and extensive nature of the lesion would have precluded surgical intervention.     

Ureteral spindle cell sarcoma in a dog

A five-year-old, female spayed Labrador retriever was presented for further investigation of an intra-abdominal mass. Abdominal exploration showed a large mass arising from the right ureter and a ureteronephrectomy was performed. Histopathology of the ureteral mass was consistent with a spindle cell sarcoma. The patient recovered well, but five months later was diagnosed with another tumour, this time in her left abdominal wall. The owners decided not to pursue further treatment and euthanasia was performed a month later.