Effect of metastatic calcification on complication rate and survival in 74 renal transplant cats (1998-2020).

OBJECTIVE: To report the incidence of metastatic calcification in cats with renal failure presenting for renal transplantation, and to determine if metastatic calcification detected prior to renal transplantation is associated with complication rates and patient survival. STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Seventy-four cats. METHODS: In imaging studies, 178 feline renal transplant recipients from 1998 to 2020 were evaluated for metastatic calcification. Demographic, clinicopathological data, intraoperative complications, postoperative complications, need for hemodialysis, and survival times were recorded. Exclusion criteria were cats lacking imaging reports and cats with gastric, renal, or tracheal/bronchial calcification alone. Univariable and multivariable analyses were performed to determine variables that were independently associated with survival. Kaplan-Meier analysis was used to generate survival plots and estimate median survival times with a 95% confidence interval (CI). RESULTS: Seventy four of 178 cats met the inclusion criteria. Fifteen of 74 (20.3%) cats had metastatic calcification prior to renal transplantation. Twelve of 74 (16.2%) cats developed calcification following transplantation, and 47 of 74 (63.5%) cats had no calcification during the study period. Median follow-up time was 472 days, with a range of 0-1825 days. Cats with pretransplant calcification had shorter median survival times (147 days) than cats without calcification (646 days) (p = .0013). Metastatic calcification pretransplant was associated with an increased risk of death by 240% (95% CI, 1.22-4.71). CONCLUSION: Metastatic calcification in renal transplant cats is a negative prognostic indicator and is associated with decreased survival times. CLINICAL SIGNIFICANCE: These findings may help guide therapeutic recommendations and owner expectations in cats undergoing renal transplantation.

cDC1 coordinate innate and adaptive responses in the omentum required for T cell priming and memory.

In the peritoneal cavity, the omentum contains fat-associated lymphoid clusters (FALCs) whose role in response to infection is poorly understood. After intraperitoneal immunization with Toxoplasma gondii, conventional type 1 dendritic cells (cDC1s) were critical to induce innate sources of IFN-γ and cellular changes in the FALCs. Unexpectedly, infected peritoneal macrophages that migrated into the FALCs primed CD8+ T cells. Although T cell priming was cDC1 independent, these DCs were required for maximal CD8+ T cell expansion. An agent-based computational model and experimental data highlighted that cDC1s affected the magnitude of the proliferative burst and promoted CD8+ T cell expression of nutrient uptake receptors and cell survival. Thus, although FALCs lack the organization of secondary lymphoid organs, cDC1s resident in this tissue coordinate innate responses to microbial challenge and provide secondary signals required for T cell expansion and memory formation.

Transpelvic urethrostomy in a female dog with congenital vestibulovaginal and urethral stenosis: A case report.

OBJECTIVE: To describe transpelvic urethrostomy (TPU) as a surgical technique for the successful treatment of vestibulovaginal and urethral stenosis in a 7 month old female spayed mixed-breed dog. STUDY DESIGN: Case report. SAMPLE POPULATION: Female spayed mixed-breed dog with obstructive vaginal tissue present on vaginal examination. METHODS: The dog presented with a history of persistent urine dribbling, stranguria, and dysuria since birth. Vaginoscopy and fluoroscopy revealed severe vestibulovaginal and urethral stenosis. An episiotomy and partial vaginectomy were performed to remove stenotic tissue. A perineal urethrostomy was attempted from a blind-ended pouch associated with the stenotic urethral tissue but was unsuccessful. The dog was repositioned in dorsal recumbency and a postpubic urethrostomy was performed. RESULTS: Six days postoperatively, incisional dehiscence occurred at the cranial aspect of the urethrostomy. The site was revised at this location using a TPU to decrease tension at the urethrostomy site. The dog recovered uneventfully with no further complications identified after surgery. Forty-two months after surgical intervention, the dog continued to show no clinical signs. CONCLUSION: Transpelvic urethrostomy may be a viable surgical alternative for dogs diagnosed with urethral stenosis.

Bilateral renal descensus and intravesicular ureteroneocystostomy for treatment of bilateral ureteral ligation and transection that occurred during ovariohysterectomy in two cats.

CASE DESCRIPTION: 6-month-old and 7-month-old spayed female domestic shorthair cats were referred because of complications associated with inadvertent bilateral ureteral ligation and transection during ovariohysterectomy. CLINICAL FINDINGS: Both cats had a 1- to 2-day history of lethargy, inappetence, and vomiting. Initial exam findings included lethargy, signs of abdominal pain, anuria, and dehydration. Clinicopathologic testing revealed azotemia and hyperkalemia. Abdominal ultrasonography revealed peritoneal effusion and bilateral pyelectasia in both cats and retroperitoneal effusion in one. Fluid analysis in both cats supported a diagnosis of uroabdomen. TREATMENT AND OUTCOME: Exploratory celiotomy was performed in both cats, and bilateral ureteral ligation and transection was confirmed. Bilateral renal descensus and ureteroneocystostomy with an intravesicular mucosal apposition technique was successfully performed in both cats. Clinicopathologic evaluation performed 1 day after surgery in one cat and 5 days after surgery in the other revealed complete resolution of azotemia. Ultrasonographic examination of the urogenital tract performed approximately 4 months after surgery in the first cat and 1 month after surgery in the second cat revealed complete resolution of renal pelvic dilation bilaterally. CLINICAL RELEVANCE: Bilateral intravesicular ureteroneocystostomy in conjunction with bilateral renal descensus was used successfully to treat bilateral ureteral transection that occurred in 2 cats during routine ovariohysterectomy. Limited treatment options currently exist for this serious complication, and euthanasia is often considered. This technique, which relies on the use of the natural surrounding tissues for successful treatment, can offer a potential treatment option to correct this uncommon but devastating complication.

Toxoplasma gondii infection in feline renal transplant recipients: 24 cases (1998-2018).

OBJECTIVE: To evaluate the effects of Toxoplasma gondii infection in feline renal transplant recipients with a preoperative seronegative or unknown serostatus (SN-UNK) for T gondii and the efficacy of lifelong prophylactic treatment of T gondii infection in feline renal transplant recipients with a preoperative seropositive serostatus (SP) for T gondii. ANIMALS: 24 cats with various serostatuses for T gondii before undergoing renal transplantation. PROCEDURES: Medical records of cats that had undergone renal transplantation from 1998 through 2018 were reviewed. Two groups of cats were identified. Before renal transplantation, the SN-UNK group cats were seronegative for T gondii (n = 4) or serostatus for T gondii was unknown (4). The SN-UNK group cats received immunosuppressive therapy but were not maintained on prophylactic treatment of T gondii infection. The SP group cats were seropositive for T gondii (n = 16) prior to initiation of immunosuppressive therapy and renal transplantation and were managed after surgery with prophylactic treatment of T gondii infection. RESULTS: All 8 SN-UNK group cats developed T gondii infections after initiation of immunosuppressive therapy and renal transplantation; T gondii infections were fatal in 6 cats. Of 16 SP group cats, 1 developed a nonfatal T gondii infection resulting in an allograft rejection episode. No SP group cats, which were managed postoperatively with prophylactic treatment, developed a fatal T gondii infection. CONCLUSIONS AND CLINICAL RELEVANCE: T gondii infection resulted in morbidity and death in immunosuppressed cats not receiving prophylactic treatment of T gondii infection after renal transplantation. Seropositive cats were acceptable candidates for renal transplantation when lifelong prophylactic treatment of T gondii infection was provided.

Loss of IL-27Rα Results in Enhanced Tubulointerstitial Fibrosis Associated with Elevated Th17 Responses.

Clinical and experimental studies have established that immune cells such as alternatively activated (M2) macrophages and Th17 cells play a role in the progression of chronic kidney disease, but the endogenous pathways that limit these processes are not well understood. The cytokine IL-27 has been shown to limit immune-mediated pathology in other systems by effects on these cell types, but this has not been thoroughly investigated in the kidney. Unilateral ureteral obstruction was performed on wild-type and IL-27Rα-/- mice. After 2 wk, kidneys were extracted, and the degree of injury was measured by hydroxyproline assay and quantification of neutrophil gelatinase-associated lipocalin mRNA. Immune cell infiltrate was evaluated by immunohistochemistry and flow cytometry. An anti-IL-17A mAb was subsequently administered to IL-27Rα-/- mice every 2 d from day of surgery with evaluation as described after 2 wk. After unilateral ureteral obstruction, IL-27 deficiency resulted in increased tissue injury and collagen deposition associated with higher levels of chemokine mRNA and increased numbers of M2 macrophages. Loss of the IL-27Rα led to increased infiltration of activated CD4+ T cells that coproduced IL-17A and TNF-α, and blockade of IL-17A partially ameliorated kidney injury. Patients with chronic kidney disease had elevated serum levels of IL-27 and IL-17A, whereas expression of transcripts for the IL-27RA and the IL-17RA in the tubular epithelial cells of patients with renal fibrosis correlated with disease severity. These data suggest that endogenous IL-27 acts at several points in the inflammatory cascade to limit the magnitude of immune-mediated damage to the kidney.

Congenital sternal defect repair in an adult cat with incomplete pentalogy of Cantrell.

CASE DESCRIPTION: A 1-year-old spayed female domestic shorthair cat was evaluated for a sternal defect and ventral abdominal wall hernia. CLINICAL FINDINGS: The cat appeared healthy. Palpation revealed a sternal defect, and the heart could be observed beating underneath the skin at the caudoventral aspect of the thorax. A 3-cm-diameter freely movable mass, consistent with a hernia, was also palpated at the cranioventral aspect of the abdomen. Thoracic radiographic and CT images revealed a sternal cleft, cranial midline abdominal wall hernia, and peritoneopericardial diaphragmatic hernia (PPDH). TREATMENT AND OUTCOME: Thoracotomy and celiotomy were performed. The sternal cleft was repaired with a porcine small intestinal submucosa graft, titanium contourable mesh plate, and interrupted 25-gauge cerclage wires. A diaphragmatic herniorrhaphy was used to correct the PPDH. Thoracic radiographs were obtained immediately after surgery to confirm repair of the sternal cleft, abdominal wall hernia, and PPDH and at 1 and 3 months after surgery to assess the surgical implants, which had not migrated and were intact with only mild bending at the cranial and caudal margins of the mesh plate. At both recheck examinations, the cat appeared healthy with no complications reported by the owner. CLINICAL RELEVANCE: A novel surgical technique was used to successfully repair a large sternal cleft in an adult cat with no postoperative complications reported. This technique may be useful for the treatment of sternal clefts in other cats. This was the first report to describe an adult cat with congenital defects consistent with incomplete pentalogy of Cantrell.

Diagnostic utility of ultrasonography for detection of the cause and location of ureteral obstruction in cats: 71 cases (2010-2016).

OBJECTIVE To assess the utility of ultrasonography to detect the cause and location of ureteral obstruction in cats and to identify factors associated with agreement between ultrasonographic and surgical findings. STUDY DESIGN Retrospective case series. ANIMALS 71 cats. PROCEDURES Medical records were searched to identify cats that had ureteral obstruction diagnosed ultrasonographically and that subsequently underwent exploratory laparotomy. Patient signalment, ultrasonographic findings, interventions performed, and surgical findings were recorded. Cause and location of ureteral obstruction as assessed by ultrasonography were compared with surgical findings. Sensitivity, specificity, and positive predictive value of ultrasonography for detection of ureteroliths and strictures were calculated. Statistical analysis was performed to identify factors associated with agreement between ultrasonographic and surgical findings. RESULTS There was significant, moderate agreement between ultrasonographic and surgical findings for the cause and location of ureteral obstruction. Signalment variables, ureter affected (left vs right), and presence of retroperitoneal effusion were not associated with this agreement. Sensitivity was 98% and 44%, specificity was 96% and 98%, and positive predictive value was 98% and 88% for detection of ureteroliths and strictures, respectively, by ultrasonography. CONCLUSIONS AND CLINICAL RELEVANCE Ultrasonography was highly sensitive for detection of ureteroliths that caused ureteral obstruction but was considerably less sensitive for detection of ureteral strictures in the study population. Future prospective studies are needed to determine the role of advanced imaging in assessing cats with ureteral abnormalities. (J Am Vet Med Assoc 2019;254:710-715).

Radiographic distribution of ureteral stones in 78 cats.

OBJECTIVE: To document the distribution of ureteral stones in cats. STUDY DESIGN: Retrospective case series. ANIMALS: Seventy-eight cats. METHODS: Abdominal radiographs with ureteral stones were reviewed. The location of stones was categorized as proximal ureter (PU), midureter (MU), or ureterovesicular junction (UVJ). The number, size, and location of stones were recorded by using the kidneys and vertebral bodies as landmarks. Stone location in cats with 1 versus multiple stones was assessed. Descriptive statistics were used to describe the incidence of ureteral stone location. RESULTS: Among cats with a single stone (44%, 34/78), 44% (15/34) had a stone in the PU, 41% (14/34) had a stone in the MU, and 15% (5/34) had a stone at the UVJ. When multiple stones were present, 61% (27/44) of cats had at least 1 stone located in the PU, 70% (31/44) had at least 1 stone located in the MU, and 34% (15/44) had at least 1 stone located at the UVJ. The L4 vertebral body most commonly marked stone location in cats with 1 stone and the most distal stone in cats with multiple stones. Stones located at the UVJ site were more common in male (37%) than in female (12%) cats (P = 0.004). Larger stone size was associated with a more proximal location (P = 0.04). CONCLUSION: Ureteral stones were more commonly located in the PU and the MU than in the UVJ. UVJ stones were more common in male than in female cats, and larger stones had a more proximal location. CLINICAL SIGNIFICANCE: This study enhances our understanding of feline ureteral stone location and identifies a correlation between stone location and stone size.

Renal cell carcinoma in a cat with polycystic kidney disease undergoing renal transplantation.

CASE SUMMARY: A 10-year-old spayed female American Shorthair cat underwent renal transplantation due to worsening chronic kidney disease secondary to polycystic kidney disease. During transplantation, the right kidney grossly appeared to be more diseased than the left and was firmly adhered to the surrounding tissues. An intraoperative fine-needle aspirate of the right native kidney revealed inflammatory cells but no evidence of neoplasia. To create space for the allograft, a right nephrectomy was performed. Following nephrectomy, the right native kidney was submitted for biopsy. Biopsy results revealed a renal cell carcinoma. Although the cat initially recovered well from surgery, delayed graft function was a concern in the early postoperative period. Significant azotemia persisted and the cat began to have diarrhea. Erythematous skin lesions developed in the perineal and inguinal regions, which were suspected to be secondary to thromboembolic disease based on histopathology. The cat's clinical status continued to decline with development of signs of sepsis, followed by marked obtundation with uncontrollable seizures. Given the postoperative diagnosis of renal cell carcinoma and the cat's progressively declining clinical status, humane euthanasia was elected. RELEVANCE AND NOVEL INFORMATION: This case is the first to document renal cell carcinoma in a cat with polycystic kidney disease. An association of the two diseases has been reported in the human literature, but such a link has yet to be described in veterinary medicine. Given the association reported in the human literature, a plausible relationship between polycystic kidney disease and renal cell carcinoma in cats merits further investigation.

Use of a modified Boari flap for the treatment of a proximal ureteral obstruction in a cat.

OBJECTIVE: To describe the use and long term outcome of a novel surgical technique developed to treat a proximal ureteral obstruction in a cat. STUDY DESIGN: Case report. ANIMALS: A 3-year-old female spayed Russian blue cat. METHODS: A 3-year-old female spayed Russian blue cat presented with a fever, decreased appetite, vomiting, and abdominal discomfort. A proximal left ureteral obstruction was noted on ultrasonographic examination. No filling defect was noted on antegrade pyelography. Due to the proximal location of the obstruction, a modification of a Boari flap was performed. In the current technique, the ureter was cut proximal to the level of obstruction, and the distal ureter was resected. A flap was created on the ventral surface of the bladder, the cut end of the ureter was pulled through the flap, and a ureteroneocystostomy was performed. The bladder was closed in a simple interrupted pattern. RESULTS: At re-evaluation 2 and 4 weeks after surgery, azotemia had resolved. According to ultrasonography, the ureteroneocystostomy site appeared to be healing, and pelvic dilation had resolved. One year later, the cat continued to do well, with no lower urinary tract signs and no abnormality noted on blood tests or ultrasonography. CONCLUSION: The tubularized bladder flap originally described by Boari was modified to create a tension-free ureteroneocystostomy, without complication. This technique relied on surrounding native tissues and resulted in long-term resolution of the ureteral obstruction. CLINICAL SIGNIFICANCE: A modified Boari flap can lead to long-term resolution of proximal ureteral obstruction in cats, without requiring stents or permanent implants.

Validation of a model of feline ureteral obstruction as a tool for teaching microsurgery to veterinary surgeons.

OBJECTIVE: To assess the content and face validity of a model of an obstructed feline ureter as a tool for teaching ureteral microsurgery. STUDY DESIGN: Prospective, experimental study. SAMPLE POPULATION: Seven expert and 11 novice microsurgeons. METHODS: The model was created from latex rubber with an inner diameter of 0.8 mm and an outer diameter of 5 mm. The "ureter" was created with an inner compartment, a thin wall, and a soft, outer layer mimicking periureteral fat. A "ureterolith" 0.8-1.2 mm in diameter was placed inside the inner compartment by using a blunt-tipped cannula. A standardized "ureterotomy" was performed by 7 expert and 11 novice microsurgeons. Both groups completed questionnaires evaluating the content and face validity of the model using subjective measures and a 5-point Likert scale. Reliability was analysed by calculation of Cronbach's α for all questions to ensure α ≥ .7. The median responses to each question were compared between groups with a nonparametric independent samples median test. P < .05 was considered significant. RESULTS: The Cronbach's α for the experts and the novices for content validity questions was .7 and .9, respectively, and for the face validity questions it was .7 and .8, respectively. The model was rated to have excellent content validity and very good face validity. CONCLUSION AND IMPACT: The model elicited positive responses from expert and novice microsurgeons and can be recommended as a tool for teaching ureteral microsurgery. A model validated by face and content measures should next be scrutinized by determination of construct, concurrent, and predictive validity by using objective measures.

Heterozygosity for P2Y12 receptor gene mutation associated with postoperative hemorrhage in a Greater Swiss Mountain dog.

A 3-year-old, female Greater Swiss Mountain dog developed a hemoperitoneum following an exploratory laparotomy and ovariohysterectomy. Platelet count, PT, APTT, and plasma von Willebrand factor antigen concentration were within RIs. A buccal mucosal bleeding time (BMBT) was prolonged. Given the probability of a hereditary thrombopathia, the dog was administered desmopressin, fresh platelet transfusions, and aminocaproic acid to control hemorrhage. Subsequently, DNA testing for the P2Y12 receptor gene mutation identified the dog as being a heterozygote (carrier). Further platelet function testing was performed following complete recovery. Results of a repeat BMBT and a point-of-care screening test using the Platelet Function Analyzer-100 (collagen/adenosine-diphosphate [ADP] test cartridge) were within RIs. Flow cytometric studies demonstrated a marked reduction in fibrinogen binding to the dog's platelets in response to ADP - adenosine diphosphate activation. Likewise, turbidimetric aggregometry revealed a complete absence of platelet aggregation in response to ADP. However, there were a normal aggregation response to the platelet agonist convulxin and a mild reduction in amplitude in response to γ-thrombin. This is the first report of a dog heterozygous for the P2Y12 receptor gene mutation exhibiting a bleeding tendency and having evidence of impaired platelet function in vitro in response to ADP activation. Given that the mutant allele for the P2Y12 thrombopathia appears to be widespread in the Greater Swiss Mountain dog breed, veterinarians need to be aware that both homozygotes and heterozygotes for this platelet receptor mutation are at risk of developing life-threatening bleeding following trauma or surgery.

Update on the Current Status of Kidney Transplantation for Chronic Kidney Disease in Animals.

Kidney transplantation is a novel treatment option for cats suffering from chronic renal failure or acute irreversible renal injury. Improvement in quality of life as well as survival times of cats that have undergone transplantation has helped the technique to gain acceptance as a viable treatment option for this fatal disease. This article reviews information regarding the optimal time for intervention, congenital and acquired conditions that have been successfully treated with transplantation, recipient and donor screening, immunosuppressive therapy, recent advances in anesthetic and surgical management, postoperative monitoring and long-term management, and troubleshooting perioperative and long-term complications.

Outcomes of ureteral surgery and ureteral stenting in cats: 117 cases (2006-2014).

OBJECTIVE: To evaluate and compare outcomes in cats following ureteral surgery or ureteral stent placement. DESIGN: Retrospective case series. ANIMALS: 117 cats. PROCEDURES: Data regarding signalment, history, concurrent disease, clinical signs, clinicopathologic tests, surgical procedures, and perioperative complications (including death) were recorded. Follow-up data, including presence of signs of chronic lower urinary tract disease, chronic urinary tract infection, reobstruction, and death, if applicable, were obtained by records review or telephone contact with owners. Variables of interest were compared statistically between cats treated with and without stent placement. Kaplan-Meier analysis and Cox regression were performed to assess differences in survival time between cats with and without ureteral stents. RESULTS: Perioperative complications referable to the urinary tract were identified in 6 of 43 (14%) cats that had ≥ 1 ureteral stent placed and 2 of 74 (3%) cats that underwent ureteral surgery without stenting. Perioperative mortality rates were similar between cats with (4/43 [9%]) and without (6/74 [8%]) stents. After surgery, signs of chronic lower urinary tract disease and chronic urinary tract infection were significantly more common among cats with than cats without stents. Nineteen of 87 (22%) cats with follow-up information available had recurrent obstruction; incidence of reobstruction did not differ between cats with and without stents. Median survival time did not differ between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: The potential for signs of chronic lower urinary tract disease and chronic infection, particularly among cats that receive ureteral stents, warrants appropriate client counseling. Judicious long-term follow-up for detection of reobstruction is recommended.

End-to-end ureteral anastomosis and double-pigtail ureteral stent placement for treatment of iatrogenic ureteral trauma in two dogs.

CASE DESCRIPTION: A 6-month-old spayed female Soft-Coated Wheaten Terrier and 8-month-old spayed female Shih Tzu were referred because of complications related to inadvertent ureteral ligation and transection during recent ovariohysterectomy. CLINICAL FINDINGS: The Soft-Coated Wheaten Terrier had a 2-day history of stranguria and polyuria that began after ovariohysterectomy. Initial examination findings were unremarkable with the exception of high rectal temperature. The Shih Tzu had a 10-day history of pyrexia, vomiting, diarrhea, and stranguria that began after ovariohysterectomy. On examination, the dog had signs of depression; clinicopathologic tests revealed hypoalbuminemia, neutrophilia, lymphocytosis, and monocytosis. Abdominal ultrasonography was performed for both dogs, revealing severe unilateral pyelectasia and hydroureter (proximal portion). TREATMENT AND OUTCOME: Both dogs underwent exploratory celiotomy; ureteral ligation and transection was confirmed. Ventral cystotomy was performed to allow retrograde placement of a double-pigtail ureteral stent into the affected ureter and renal pelvis. End-to-end ureteral anastomosis was performed over the stent with the aid of an operating microscope. Stent position was confirmed via fluoroscopy, and incisions were closed routinely. Dogs continued to have intermittent signs of stranguria until stent removal via cystoscopy 6 or 7 weeks after surgery. Ultrasonographic examination of the urogenital tract was performed 2 or 4 months after surgery, revealing resolution of pyelectasia and hydroureter. CLINICAL RELEVANCE: The surgical technique used provided a viable option for preserving renal function in dogs with focal, iatrogenic ureteral trauma. Use of a ureteral stent facilitated ureteral anastomosis and minimized postoperative complications.

Septicemia and Infection due to ESBL-producing K. pneumoniae Following Feline Renal Allograft Transplantation.

A 12 yr old castrated male domestic longhair underwent renal transplantation for treatment of chronic interstitial nephritis. Full-thickness intestinal biopsies obtained prior to transplantation revealed mild enteritis. Twelve months following transplantation, the patient underwent surgery for resection of a mesenteric mass causing septic peritonitis. The mesenteric mass was resected and an intestinal resection and anastomosis was performed. Extended-spectrum-ß-lactamase producing Klebsiella pneumoniae was cultured from the resected tissue and urinary tract. Bacterial rods were noted to be circulating in the bloodstream, causing septicemia. Despite aggressive treatment of the septic peritonitis and septicemia using surgical debridement, drain placement, aggressive antibiotic therapy with IV meropenem, and vasopressor support, the patient succumbed to persistent hypotension and suffered cardiopulmonary arrest. Extended-spectrum-ß-lactamase-producing bacteria are of growing concern in human and veterinary medicine, maintaining susceptibility often only to carbapenem and aminoglycoside antibiotics. Resistance to even those antibiotics is emerging. Veterinary patients with a history of antibiotic therapy, central venous or urinary catheterization, immunosuppression, enteric surgery, and an extended stay in the intensive care unit may be predisposed.

Retroperitoneal fibrosis in feline renal transplant recipients: 29 cases (1998-2011).

OBJECTIVE: To evaluate features, treatment, and prognosis associated with retroperitoneal fibrosis that developed after renal transplantation in cats. DESIGN: Retrospective case series. ANIMALS: 29 cats. PROCEDURES: Medical records of cats that developed retroperitoneal fibrosis after renal transplantation at the College of Veterinary Medicine, University of Pennsylvania, between 1998 and 2011 were reviewed for signalment, date of transplantation, age, results of urine and blood analyses, blood pressure at the time of diagnosis, infectious disease and medication anamneses, anesthetic protocols, and intraoperative complications. RESULTS: Of 138 transplant recipients, 29 (21%) developed clinically important retroperitoneal fibrosis. Nineteen (66%) were male, and median age at the time of renal transplantation was 8 years (range, 4 to 13 years). Median number of days after transplantation to diagnosis of retroperitoneal fibrosis was 62 (range, 4 to 730 days; mean, 125 days). The most common clinical signs were lethargy and anorexia. All affected cats were azotemic (BUN concentration > 32 mg/dL; creatinine concentration > 2.0 mg/dL) and anemic (PCV < 35%) at the time of retroperitoneal fibrosis diagnosis, although cats were nonazotemic at the time of discharge following transplantation, and anemia was less pronounced. Twenty-five cats successfully underwent surgical ureterolysis in which scar tissue was dissected away from the allograft ureter to relieve extraluminal compression. Retroperitoneal fibrosis recurred in 6 (22%) cats a median of 180 days (range, 8 to 343 days) following the original diagnosis and was treated successfully by repeated ureterolysis. CONCLUSIONS AND CLINICAL RELEVANCE: Retroperitoneal fibrosis occurred in a substantial percentage of feline renal transplant recipients and should be considered a differential diagnosis in any feline renal transplant recipient with clinicopathologic findings, imaging abnormalities, or signs suggestive of obstructive uropathy.

Osteomyelitis of the coxofemoral joint due to Mycobacterium species in a feline renal transplant recipient.

A 4-year-old castrated male Russian Blue cat was evaluated for acute right hind limb lameness 18 months after receiving a renal transplant. Radiographs showed a subluxated right femoral head and lysis of the acetabulum and femoral neck. A femoral head and neck ostectomy was performed on the right coxofemoral joint. Histologic evaluation of the right femoral head revealed lesions indicative of a chronic, granulomatous osteomyelitis and periostitis associated with an intralesional Mycobacterium species. However, the cat's clinical condition declined despite treatment and the owner elected humane euthanasia. All renal transplant recipients receive immunosuppressive therapy to prevent allograft rejection. The non-tuberculous mycobacterial infection of the coxofemoral joint was thought to develop secondary to long-term immunosuppressive treatment. This report illustrates the need to consider these rare opportunistic infections even many months to years following renal transplantation. Early awareness, stringent immunosuppressive drug monitoring and targeted treatment once a diagnosis has been made may be important in the successful management and prevention of mycobacterial infections in this population of patients.