Perirenal pseudocysts in 26 cats

OBJECTIVE: To evaluate clinical features, anatomical location, nature of pseudocyst fluid, results of surgical treatment and links with underlying renal disease in cats with perirenal pseudocysts. DESIGN: A retrospective study of 26 affected cats, including 8 treated surgically. RESULTS: Nineteen (73%) affected cats were male. The median age was 11 years. Most presented for abdominal enlargement and had varying degrees of renal dysfunction on presentation. Thirteen cats (50%) had bilateral pseudocysts. The pseudocyst fluid was a transudate or modified transudate in all cases. All surgically treated cats had subcapsular perirenal pseudocysts. Associated renal lesions were identified in all cats that had renal biopsies or detailed ultrasonographic examinations. Surgery relieved clinical signs but did not stop progression of renal disease. Cats survived a median of 9 months after surgery and survival was correlated statistically to degree of azotaemia at presentation. Percutaneous drainage of pseudocysts was ineffective in controlling long-term fluid accumulation. CONCLUSIONS: Subcapsular perirenal pseudocysts are formed in cats by accumulation of transudate between the capsule and parenchyma of the kidney as a result of underlying parenchymal disease. Pseudocyst formation can occur at variable stages of renal dysfunction. Resection of the pseudocyst wall is usually effective in eliminating signs but does not stop progression of renal disease. The prognosis for cats with pseudocyst formation is related to the degree of renal dysfunction at time of diagnosis.     

PERIRENAL EFFUSION IN DOGS AND CATS WITH ACUTE RENAL FAILURE

Perirenal fluid accumulation has been described as an ultrasonographic feature of urine leakage, hemorrhage, abscessation, or neoplasia. The purpose of this retrospective study was to report perirenal effusion as an additional ultrasonographic finding in canine and feline patients with acute renal failure. The causes of acute renal failure in 18 patients included nephrotoxicity (4), leptospirosis (3), ureteral obstruction (2), renal lymphoma (2), ureteronephrolithiasis (2), prostatic urethral obstruction (1) and interstitial nephritis and ureteritis (1). An underlying cause was not identified in three patients. The sonographic finding of perirenal fluid was bilateral in 15 patients. Unilateral perirenal fluid was identified ipsilateral to the site of ureteric obstruction in two patients. Large effusions extended into the caudal retroperitoneal space. Additional sonographic findings suggestive of renal parenchymal disease included mild (5), moderate (5) or severe (2) pyelectasia, increased renal echogenicity (11), increased (9) or decreased renal size (2) and ureteral and/or renal calculi (3). There did not appear to be an association between the volume of perirenal fluid and the severity of renal dysfunction. All patients with large effusions underwent euthanasia. Perirenal fluid developing in acute renal failure is thought to be an ultrafiltrate associated with tubular back-leak into the renal interstitium that overwhelms lymphatic drainage within the perirenal and retroperitoneal connective tissues although obstruction to urine flow may also play a role. Localized perirenal retroperitoneal free fluid may be a useful ultrasonographic feature to assist with the characterization of, and determination of prognosis in, patients with suspected renal disease.     

UNILATERAL PERINEPHRIC PSEUDOCYST OF UNDETERMINED ORIGIN IN A DOG

Unilateral perinephric pseudocyst of undetermined origin was diagnosed in a 13^1/2 year old dog with a history of recurrent urinary tract infections. A presumptive diagnosis of pseudocyst was based on radiographic and sonographic findings. In survey radiographs, asymmetrical unilateral renomegaly was seen. The mass was anechoic. There was absence of opacification of the mass during excretory urography. A celiotomy was performed for removal of the perinephric mass, and histologic review of this structure confirmed it to be a pseudocyst. Perinephric accumulation of fluid is a rare condition in domestic animals. Seven examples of perinephric pseudocysts have been previously reported in the cat. Predominant clinical findings include progressive abdominal distension and nonspecific signs of renal disease. The presence of unilateral or bilateral renomegaly is a characteristic radiographic feature. This clinical report describes the first case of perinephric pseudocyst diagnosed in the dog.     

Pancreatic Pseudocysts in 4 Dogs and 2 Cats: Ultrasonographic and Clinicopathologic Findings

Pancreatic pseudocysts were diagnosed in 4 dogs and 2 cats based on ultrasonographic and clinicopathologic findings. All 6 animals had a clinical diagnosis of pancreatitis. Five of 6 pseudocysts were in the left pancreatic limb, and in 1 cat the pseudocyst was in the pancreatic body region. Cyst size ranged from 2 x 2 cm to 7 x 6 cm. All pseudocysts had anechoic regions that were aspirated using ultrasound guidance for diagnostic and therapeutic purposes. No morbidity was associated with the aspiration procedures. Cytologically the pseudocyst fluid was aseptic in all patients and had low numbers of inflammatory cells in 5 of 6 patients. All animals had high lipase activity in the pseudocyst fluid and in 2 dogs and 1 cat the lipase activity in the fluid was greater than in serum. Three of the 4 dogs were managed medically. In the 1 dog that had long-term follow-up ultrasound examination, the pseudocyst persisted for several days following aspiration and had disappeared 8 months after diagnosis. All 3 of these dogs were clinically normal 1.5-4 years after presentation. The 4th dog underwent surgical exploration and was euthanized shortly thereafter because of bronchopneumonia and chronic pancreatitis. The 2 cats died 10 days and 2 months, respectively, following initial diagnosis of the pseudocyst, but necropsies were not performed in either case. Ultrasound-guided fine-needle aspiration of pancreatic pseudocysts and clinicopathologic evaluation of cystic fluid are useful for diagnosis of pancreatic pseudocysts.     

Post-traumatic paraureteral urinoma in a cat

A retroperitoneal urinoma (uriniferous pseudocyst) was diagnosed in a domestic shorthair cat exhibiting a sublumbar swelling two weeks after a road traffic accident. Plain radiography revealed a soft tissue opacity in the left retroperitoneal space. Intravenous urography and fine-needle aspiration were diagnostic. Contrast was seen pooling in the dilated ipsilateral renal pelvis and proximal ureter. Fluid aspirated from the retroperitoneal space had a creatinine level five times that of serum. Surgical drainage followed by nephrectomy and omentalisation of the pseudocyst was curative.     

BILATERAL PERINEPHRIC PSEUDOCYSTS AND POLYCYSTIC KIDNEYS IN A FERRET

A 3-year-old castrated male domestic ferret was evaluated for abdominal distention. Survey lateral and dorsoventral abdominal radiographs were made. There were two soft tissue radiopacities consistent with grossly enlarged kidneys displacing small bowel and colon cranially, ventrally and caudally. Abdominal ultrasound was performed and revealed bilateral perinephric pseudocysts and polycystic kidneys. The perinephric pseudocysts were found to be dilated renal capsules on exploratory surgery and were drained. On follow up examinations, the pseudocysts were drained by ultrasound-guided paracentesis. The perinephric cyst fluid was distinguished from urine by measuring creatinine concentration and plans were made to resect the renal capsules due to rapid re-accumulation of pseudocyst fluid. The ferret's condition deteriorated and euthanasia was performed. Post-mortem examination was declined by the owner. Perinephric pseudocysts are rare and this is the first published report in a ferret. Ultrasound examination is the most rapid, accurate and non-invasive method for diagnosis of perinephric pseudocysts.     

Unilateral perinephric pseudocyst secondary to hydronephrosis in a C57BL/6J mouse

A 9-month-old C57BL/6J mouse had progressive abdominal distension over a 1-week period, and a distended left renal capsule was discovered at postmortem examination. Incision of the capsule showed a tan, cloudy fluid that separated the renal capsule and the remnant left kidney. Microscopically, the capsule was significantly separated from the renal parenchyma by clear space and necrotic cellular debris. The majority of the lining of the renal capsule was composed of fibrous connective tissue and lacked an epithelial lining, consistent with a subcapsular perinephric pseudocyst. In addition, attached to intermittent portions of the renal capsule were thin rims of compressed cortical tissue lined by transitional epithelium. The finding of remnant cortical tissue lined by transitional epithelium is consistent with severe hydronephrosis and indicates that the hydronephrosis preceded the formation of the perinephric pseudocyst. To our knowledge, this is the first case report to characterize a perinephric pseudocyst secondary to severe hydronephrosis in a mouse.     

Lesions of toxoplasmosis in the perirenal adipose tissue of aborted kids

Extract

Madam:—During July of 1986, a number of aborted Angon kids were received in our laboratory for routine diagnosis on the cause of abortion and they were diagnosed pathologically and serologically as being due to toxoplasmosis. Apart from classical microscopiallesions in the brain, lung, myocardium, liver and kidney of the aborted kids and the placentae of the does, we noted a prominent steatitis and periarteritis in the perirenal adipose tissue. These lesions were multiple and random in distribution and were characterised by infiltrations of mononuclear cells (Fig. 1). The changes were consistently present in the perirenal fat of all aborted foetuses in which Toxoplasma infection was established. Occasionally, Toxoplasma pseudocysts could be found in association with these inflammatory foci (Fig. 1.). In addition, pseudocysts and occasional groups of tachyzoites were found in the other tissues.     

LAPAROSCOPIC SONOGRAPHY IN THE URINARY SYSTEM

This work reports the use of laparoscopic-transducer sonography for the examination of the urinary system in a swine model. Animals underwent a two-phase study. In the first phase, the urinary system was examined using laparoscopic sonography. In the second a partial ureteral obstruction was induced, and sonographic changes were recorded and evaluated. Sonography was used to evaluate kidneys, ureters, and bladder. Anatomic structures were evaluated and the following pathological findings were identified: renal cysts, one polycystic kidney, dilation of the renal pelvis, hydronephrosis, and one perirenal pseudocyst. Where necessary, contrast digital fluoroscopy (excretory urography and retrograde ureteropyelography) was also performed. Laparoscopic sonography mainly is used for evaluation prior to laparoscopic surgery to guide decisions relating to surgery. The quality of the images obtained laparoscopically is superior to that of percutaneous or transabdominal images, because artifacts are reduced and the contact surface of the transducer is placed directly over the study area. Laparoscopic sonography proved highly effective for studying renal and ureteral disorders prior to minimally invasive surgery.     

IMAGING OF A CAT WITH PERIRENAL PSEUDOCYSTS

A 16-year-old, neutered male, domestic short hair cat had abdominal distension and systemic hypertension. Radiography, ultrasonography, excretory urography, and renal scintigraphy were performed to establish the diagnosis and implement appropriate treatment. Bilateral perirenal pseudocysts were confirmed surgically and histopathologically. Following bilateral renal capsulectomy, systemic hypertension decreased and global glomerular filtration rate improved to normal limits. Multiple imaging modalities helped establish the diagnosis and guided implementation of appropriate treatment.     

URINOMA (PARA-URETERAL PSEUDOCYST) IN A DOG

A urinoma is an encapsulated extravasation of urine. In this case history report, the radiographic and ultrasonographic features of a urinoma in a dog are described. The dog presented with a palpable mass in the right flank which developed following ovariohysterectomy. Urinoma was considered when ultrasonographically, a sharply marginated, anechoic mass immediately caudal to the right kidney, ipsilateral hydroureter and hydronephrosis were detected. Extravasation of contrast medium was not seen during excretory urography. A fluid-filled retroperitoneal mass adjacent to a transected ureter was found at exploratory laparotomy. The diagnosis of urinoma (para-ureteral pseudocyst) and hydronephrosis was confirmed histopathologically.     

Transitional cell carcinoma forming a perirenal cyst in a cat

An eight-year-old, neutered male Burmese cat presented with five days vomiting and anorexia. Physical examination, clinical pathology and diagnostic imaging findings suggested a perirenal pseudocyst. After partial resection of the perirenal capsule clinical signs temporarily resolved, but the cat was euthanased 34 days postoperatively as a result of seizures and recurrence of vomiting. Postoperative histopathology showed neoplastic transitional cells within and lining the resected perirenal capsule; a diagnosis of transitional cell carcinoma was confirmed post-mortem. To the authors' knowledge, this is the first report of this presentation of transitional cell carcinoma. Transitional cell carcinoma should be a differential diagnosis for the aetiology of perirenal pseudocyst.     

Retroperitoneal fibrosis in four cats following renal transplantation

Four cats developed fibrosis within the retroperitoneal space following renal transplantation. In human transplant patients, retroperitoneal fibrosis is an uncommon complication following surgery and may be secondary to operative trauma, infection, deposition of foreign material in the operative field, urinary extravasation, and perirenal hemorrhage caused by trauma to the allograft. Possible causes of fibrosis in the cats of this report include abdominal inflammation associated with allograft rejection, pyelonephritis, and septic peritoneal effusion. All of the cats of this report were readmitted to the veterinary teaching hospital following renal transplantation because of recurrence of azotemia 1 to 5 months after transplantation. Abdominal ultrasonography revealed a 2- to 4-mm-thick capsule surrounding the allograft in 2 of 4 cats, hydronephrosis in 4 cats, and hydroureter proximally in 2 cats. An exploratory laparotomy was performed in all cats to remove the fibrotic tissue causing the ureteral obstruction. Normal renal function was restored in all cats following surgery. Histologic evaluation of biopsy specimens revealed smooth muscle (3 cats) and fibrous connective tissue (4). All 4 cats, regardless of the cause, responded well to surgical resection of the scar tissue that was causing a ureteral obstruction. None of the cats had recurrence of obstruction following surgery.     

Detection of Leishmania (L.) chagasi in canine skin

Tritrichomonas foetus is a serious veterinary pathogen that causes bovine trichomonosis, a sexually transmitted disease that eventually leads to abortion and infertility. T. foetus has a simple life cycle that consists of only a trophozoitic form. During unfavorable environmental conditions, the trophozoites, which are polar and flagellated, can adopt a spherical shape and internalize their flagella. These rounded organisms are known as pseudocysts. Although it is currently assumed that T. foetus pseudocyst formation is reversible and that it represents a response to stressful conditions, there are no reports showing the presence of this form in vivo. For this reason, the aim of this study was to verify whether T. foetus pseudocysts are encountered in naturally infected bulls. Towards this goal, fresh preputial samples obtained from seven mature bulls that were naturally infected with T. foetus were analyzed using complementary techniques, such as video microscopy, fluorescence microscopy, scanning and transmission electron microscopy. The analyses revealed that approximately 55% of the parasites were in pseudocyst form in each preputial sample, whereas approximately 25% of T. foetus displayed pear-shaped bodies. Previous research demonstrated that in vitro T. foetus pseudocysts are able to divide by a budding process. Here, this division mode was observed in approximately 20% of fresh T. foetus obtained from preputial bovine samples. Thus, this study shows that in infected bulls, pseudocysts are present and occur more frequently than the pear-shaped parasites.     

Left- and right-sided laparoscopic-assisted nephrectomy in standing horses with unilateral renal disease

Objective— To describe a technique for, and outcome after, left‐ or right‐sided laparoscopic‐assisted nephrectomy in standing horses with unilateral renal disease. Study Design— Clinical report. Animals— Horses (n=3) with unilateral renal disease. Methods— Horses were sedated with detomidine (0.01 mg/kg intravenously [IV]) and levomethadone (0.05 mg/kg IV). Paravertebral anesthesia and infiltration‐anesthesia with 2% lidocaine were used to create a surgical field incorporating the 17th intercostal space and paralumbar fossa. Two separate, ipsilateral portals and a mini‐laparotomy were used. The perirenal peritoneum was horizontally incised (10–15 cm) using endoscissors and the incision digitally enlarged for manual dissection of the perirenal fat and kidney mobilization. The renal vessels and ureter were individually dissected, ligated, and transected under laparoscopic observation and the kidney removed. The perirenal and laparotomy peritoneal defects were not closed; and the laparotomy was closed in a multilayered fashion. The transverse abdominal muscle was apposed in a continuous pattern using 1 polyglactin 910, the subcutaneous tissue (simple continuous pattern) and skin (simple interrupted pattern) with 2–0 polyglactin 910. Results— Left (2) and right (1) sided laparoscopic‐assisted nephrectomy (1 nephrolithiasis, 2 hydronephrosis) was performed successfully. Sedation and local anesthesia was adequate for intraoperative immobilization and analgesia. No intraoperative complications occurred. Incisional seroma formation and fever occurred on days 3 and 4 in 1 horse and resolved with medical management. Conclusion— Laparoscopic‐assisted nephrectomy can be used for removal of the left or right kidney in standing horses with unilateral kidney disease. Clinical Relevance— To avoid risks associated with general anesthesia and to reduce surgical trauma, laparoscopic‐assisted nephrectomy can be performed in the standing sedated horse using a 2 portal technique and a mini‐laparotomy.     

Renal agenesis in an alpaca cria

A 4-day-old alpaca cria presented for inappetence that responded to symptomatic treatment. The cria re-presented with acute signs of inappetence and azotaemia. The azotaemia persisted despite intravenous fluid therapy. There was no right kidney on ultrasound and there appeared to be perirenal oedema around the left kidney. A diagnosis of right renal agenesis and acute renal failure of the left kidney was made. The cria failed to improve and was euthanased. Necropsy examination confirmed right renal agenesis and agenesis of the right ureter and right renal artery. A section of left kidney submitted for histological examination revealed diffuse, acute, marked tubular degeneration and nephrosis. The cause of the renal failure in the left kidney was not determined.     

ULTRASONOGRAPHIC FEATURES OF PYONEPHROSIS IN DOGS

Pyonephrosis refers an infected hydronephrotic kidney which arise from pyelonephritis followed by exudate accumulation in a dilated renal pelvis or hydronephrosis followed by ascending infection. Pyonephrosis may cause serious systemic complications, making prompt and reliable diagnosis critical. Clinical and ultrasonographic findings are used for the diagnosis of pyonephrosis in humans, but these findings have not been investigated in dogs. We reviewed ultrasonographic features in pyonephrosis in 18 dogs. Ten dogs with hydronephrosis were also evaluated to compare with the pyonephrosis patients. In most dogs with pyonephrosis, hyperechoic contents completely filled the dilated renal pelvis (n=8) or a fluid‐debris level was observed (n=8). Hyperechoic contents were dispersed in renal pelvis in only two of the 18 dogs. Hyperechoic, edematous mesentery, and peritoneal and retroperitoneal effusion, which represented peritoneal and retroperitoneal inflammation, were observed in the perinephric region in 11 dogs. Compared with pyonephrosis, and as expected, hydronephrosis was characterized by anechoic contents within the urine‐filled collecting system and there were no definitive findings to suspect peritonitis. Thus, there is a distinct difference in the sonographic appearance of pyonephrosis vs. hydronephrosis in dogs.     

Renal extramedullary plasmacytoma in a dog

A 10-year-old, intact male Siberian husky dog was presented for a suspected left renal cyst. Computed tomography (CT) identified a large, left kidney mass with retroperitoneal hemorrhage. A left-sided nephrectomy was performed, and histopathology confirmed a renal plasmacytoma. Perioperative screening for multiple myeloma was negative. The dog was lost to follow-up and was euthanized 11 months after surgery. A necropsy was not performed. To the authors’ knowledge, this is the first case of renal extramedullary plasmacytoma in a dog.Key clinical message:This report describes the clinical presentation, and laboratory, diagnostic imaging, and surgery findings of a case of renal extramedullary plasmacytoma in a dog.     

Lesions of perirenal hemorrhage syndrome in growing turkeys

Turkeys from six market flocks were examined at 8 to 19 weeks of age to assess morphologic lesions of perirenal hemorrhage syndrome (PHS). PHS was diagnosed in 165 of 715 turkeys necropsied, and 82 turkeys served as age- and weight-matched controls. The most consistent gross findings were rounded pectoral muscles of normal color, ingesta-filled crops and gizzards, variable retroperitoneal perirenal hemorrhage, a swollen dark red and light purple spleen, congested intestinal blood vessels, and pulmonary edema and/or hemorrhage. The main histologic lesions of PHS were perivascular edema in lungs and kidneys, vascular congestion of various organs, renal perivenous hemorrhage, and proliferative arterial and arteriolar lesions in the spleen and kidneys that were more severe than those in controls. Heart weights, including mean relative weights of the right and combined left ventricles and interventricular septa, were significantly greater in turkeys that died with PHS than in controls. Scores for tibial dyschondroplasia and "breast blisters" were more severe in turkeys that died with PHS than in controls. The cardiovascular system appeared to be the PHS target system.     

Avulsion of the left renal artery following blunt abdominal trauma in a dog

A two-year-old, male, crossbreed dog was presented three days after being involved in a motor vehicle accident. Survey radiographs showed multiple pelvic fractures and poor intraperitoneal and retroperitoneal contrast. Ultrasound indicated the left kidney to be hypoperfused, and a thrombus was visible at the origin of the left renal artery. Ultrasound-guided fine needle aspiration confirmed that free fluid visible in the retroperitoneal and peritoneal spaces was blood. No improvement was seen in the renal perfusion over a 43 hour period, and the intestinal hypomotility worsened over this time. The haemoperitoneum and the haemoretroperitoneum both resolved ultrasonographically within this 43 hour period. Surgery confirmed an avulsion of the left renal artery approximately 10 mm from its origin on the aorta and an avulsion of the left ureter at the ureteropelvic junction. An ureteronephrectomy was performed on the left kidney and the dog recovered uneventfully.