Ultrafiltration during intermittent hemodialysis in dogs with acute kidney injury.

BACKGROUND: Ultrafiltration is performed to alleviate fluid overload in dogs with acute kidney injury (AKI) undergoing intermittent hemodialysis (IHD). OBJECTIVES: To describe prescription patterns for ultrafiltration in dogs receiving IHD for AKI and risk factors for ultrafiltration-related complications. ANIMALS: Seventy-seven dogs undergoing 144 IHD treatments between 2009 and 2019. METHODS: Medical records of dogs receiving IHD for AKI were reviewed. The initial 3 IHD treatments in which ultrafiltration was prescribed were included. Ultrafiltration-related complications were defined as those requiring an intervention such as transient or permanent discontinuation of ultrafiltration. RESULTS: Mean fluid removal rate per treatment was 8.1 ± 4.5 mL/kg/h. Ultrafiltration-related complications occurred in 37/144 (25.7%) of treatments. Hypotension was rare (6/144, 4.2% of treatments). No ultrafiltration-related complications resulted in deaths. The mean prescribed fluid removal rate per treatment was higher in dogs with ultrafiltration-related complications than without (10.8 ± 4.9 mL/kg/h vs 8.8 ± 5.1 mL/kg/h, respectively; P = .03). The mean delivered fluid removal rate per treatment was significantly lower in dogs with UF-related complications compared to those without complications (6.8 ± 4.0 mL/kg/h vs 8.6 ± 4.6 mL/kg/h, respectively; P = .04). Variables associated with ultrafiltration-related complications (P < .05) included central venous oxygen saturation, body temperature before IHD treatment, total extracorporeal circuit volume and BUN at the end of IHD treatment. CONCLUSIONS AND CLINICAL IMPORTANCE: Ultrafiltration during IHD in dogs with AKI is overall safe. Higher prescribed ultrafiltration rates were associated with increased risk of complications. Decrease in central venous oxygen saturation is associated with ultrafiltration-related complications, emphasizing the utility of in-line blood monitoring.

Bilateral external jugular vein anomalies preventing hemodialysis catheter placement in a cat with anuria secondary to Lilium species intoxication.

Case series summary: A 2-year-old female spayed Abyssinian cat was evaluated for lethargy and inappetence that first occurred approximately 4 days prior. In addition, urination had not been observed by the owner for 5 days. A Lilium species plant had been brought into the house approximately 5 days before initial evaluation, and intoxication was therefore suspected. Bloodwork revealed anemia, severe azotemia and hyperkalemia. As the cat was anuric with severe azotemia, hyperkalemia and fluid overload, intermittent hemodialysis was recommended. Attempts were made to place a hemodialysis catheter into the external jugular veins bilaterally, but after initial successful venipuncture, the instrumentation would not pass into either vein. During fluoroscopic angiography, no internal jugular veins or external jugular veins caudal to the thoracic inlet were visualized and venous drainage from the head occurred via the vertebral veins. Owing to the anomalous anatomy in the cervical region, a hemodialysis catheter could not be placed into either jugular vein. Alternative sites for the placement of an extracorporeal catheter were discussed with the owner, but humane euthanasia was elected. Relevance and novel information: To the authors' knowledge, this is the first report of a cat with bilateral external jugular vein anomalies resulting in blind endings that did not communicate with the vena cava. This was discovered during attempts to place a hemodialysis catheter for the management of anuric renal failure secondary to Lilium species intoxication. While this anatomical variation is likely uncommon, it is an important differential to consider when faced with challenging external jugular vein catheterizations in feline patients.

Diagnosis, management, and outcome of urethral obstruction secondary to the capsule associated with the artificial urethral sphincter device.

BACKGROUND: Urethral obstruction secondary to artificial urethral sphincter (AUS) implantation is a recognized complication in dogs. However, urethral obstruction secondary to AUS-associated capsule formation has been described rarely. HYPOTHESIS: Describe clinical and diagnostic findings, management, and outcome in 6 dogs with urethral obstruction secondary to AUS-associated capsule formation. ANIMALS: Six client-owned dogs. METHODS: Retrospective study. Medical records between January 1, 2010, and June 30, 2021, were reviewed to identify dogs with urethral obstruction associated with the AUS device. RESULTS: The AUS device was implanted a median of 884 days (range, 20-2457 days) before presentation for urethral obstruction. Median age at time of urethral obstruction was 4.7 years (range, 3.1-8.7 years). Clinical signs at the time of urethral obstruction were stranguria (n = 4), pollakiuria (3), weak urine stream (2), and worsened urinary incontinence (1). In all dogs, the urethra was noted to be stenotic during urethroscopy and positive contrast cystourethrography. All dogs underwent surgery, and a fibrous capsule associated with the AUS was found to be causing urethral stenosis. Resolution of urethral obstruction occurred in all dogs after transection or removal of the capsule. Positive bacterial cultures were obtained from the capsule, AUS, or both in all dogs. Recurrence of urethral obstruction had not occurred in any dog at the time of follow-up. CONCLUSIONS AND CLINICAL IMPORTANCE: Urethral obstruction secondary to capsule formation is an uncommon but clinically important complication associated with use of the AUS. Continued investigation is needed to evaluate this complication more thoroughly, and its possible association with infection.

Urolithiasis in dogs: Evaluation of trends in urolith composition and risk factors (2006-2018).

BACKGROUND: Urolithiasis is a common and often recurrent problem in dogs. OBJECTIVE: To evaluate trends in urolith composition in dogs and to assess risk factors for urolithiasis, including age, breed, sex, neuter status, urolith location, and bacterial urolith cultures. SAMPLE POPULATION: A total of 10 444 uroliths and the dogs from which they were obtained. METHODS: The laboratory database at the UC Davis Gerald V. Ling Urinary Stone Analysis Laboratory was searched for all urolith submissions from dogs between January 2006 and December 2018. Mineral type, age, breed, sex, neuter status, urolith location, and urolith culture were recorded. Trends were evaluated and variables compared to evaluate risk factors. RESULTS: Calcium oxalate (CaOx) and struvite-containing uroliths comprised the majority of all submissions from dogs, representing 47.0% and 43.6%, respectively. The proportion of CaOx-containing uroliths significantly decreased from 49.5% in 2006 to 41.8% in 2018 (P = .006), with no change in the proportion of struvite-containing urolith submissions. Cystine-containing uroliths comprised 2.7% of all submissions between 2006 and 2018 and a significant nonlinear increase in this mineral type occurred over time (1.4% of all submissions in 2006 to 8.7% in 2018; P < .001). Of all cystine-containing uroliths, 70.3% were from intact male dogs. Age, breed, and sex predispositions for uroliths were similar to those previously identified. CONCLUSIONS AND CLINICAL IMPORTANCE: Although calcium oxalate- and struvite-containing uroliths continue to be the most common uroliths submitted from dogs, a decrease in the proportion of CaOx-containing uroliths and an increase in the proportion of cystine-containing uroliths occurred during the time period evaluated.

Urolithiasis in cats: Evaluation of trends in urolith composition and risk factors (2005-2018).

BACKGROUND: Urolithiasis is an important upper and lower urinary tract disease in cats that results in morbidity and mortality. OBJECTIVE: To describe trends in composition of uroliths in cats and evaluate risk factors related to age, breed, sex, urolith location, and bacterial urolith cultures. SAMPLE POPULATION: A total of 3940 uroliths and the cats from which they were obtained. METHODS: The database of the UC Davis Gerald V. Ling Urinary Stone Analysis Laboratory was searched for all urolith submissions from cats between January 2005 and December 2018. Mineral type, age, breed, sex, and urolith location and culture results were recorded. Trends were evaluated and variables compared to evaluate risk factors. RESULTS: A significant decrease in the proportion of calcium oxalate (CaOx)-containing uroliths occurred over time (P = .02), from 50.1% (204/407) of all submissions in 2005 to 37.7% (58/154) in 2018. In contrast, the proportion of struvite-containing uroliths increased significantly (P = .002), from 41.8% (170/407) in 2005 to 54.5% (84/154) in 2018. The proportion of CaOx-containing uroliths in the upper urinary tract was significantly higher compared to the proportion of other urolith types in the upper urinary tract. Urate-containing uroliths were the third most common type (361/3940, 9.2%). Overall, sex and age predispositions were similar to those reported previously. CONCLUSIONS AND CLINICAL IMPORTANCE: The decrease in the proportion of CaOx-containing uroliths and increase in the proportion of struvite-containing uroliths warrants investigation. Further education regarding the efficacy of medical dissolution of struvite-containing uroliths is recommended.

Association of ultrasonographic features with histologic findings in 71 dogs with protein-losing nephropathy (2008-2018).

OBJECTIVE: To determine whether ultrasonographic features in dogs with protein-losing nephropathy (PLN) were associated with renal biopsy findings and compare corticomedullary ratios between dogs with PLN versus non-renal disease. ANIMALS: 71 dogs with PLN and 33 dogs without renal disease. PROCEDURES: Medical records and archived ultrasonographic images for dogs with PLN that underwent renal biopsy between 2008 and 2018 were reviewed. Corticomedullary ratios were measured. RESULTS: In dogs with PLN, median serum creatinine and BUN concentrations and urine-protein-to-creatinine-ratio prior to renal biopsy were 3.4 mg/dL (interquartile range [IQR], 1.2 to 5.3 mg/dL), 80 mg/dL (IQR, 28 to 105 mg/dL), and 11.4 (IQR, 6.4 to 18.3), respectively. Histologic abnormalities within the tubulointerstitial space were associated with cortical echogenicity. Gastric wall thickness > 5 mm was associated with a histologic diagnosis of acute glomerular disease. Dogs with immune complex-mediated glomerular disease were more likely to have abnormal gastric mural architecture. Other ultrasonographic features of the kidneys, liver, and stomach and the presence of ascites did not help to differentiate immune complex-mediated from non-immune complex-mediated glomerular disease, acute from chronic disease, or amyloid from non-amyloid disease or distinguish whether tubulointerstitial disease was present or absent. Median left corticomedullary ratio for 66 dogs with PLN (1.2) was significantly higher than that for the 33 dogs without renal disease (1.0). CLINICAL RELEVANCE: Ultrasonographic features were poorly associated with specific pathological disorders in dogs with PLN. In this study, the corticomedullary ratio was higher in dogs with PLN, indicating the presence of cortical thickening, but the clinical relevance is unknown.

Risk factors associated with progressive increases in serum creatinine concentrations in cats with cancer receiving doxorubicin.

BACKGROUND: Azotemia occurs in cats administered doxorubicin, but risk factors have not been explored. OBJECTIVE: To determine incidence of progressive increases in serum creatinine concentration in cats with cancer receiving doxorubicin in single or multiagent chemotherapy protocols and associated risk factors. ANIMALS: Seventy cats with cancer receiving doxorubicin. METHODS: A retrospective study (2007-2017) of cats with indices of kidney function recorded before and after doxorubicin administration was reviewed. Cats diagnosed with kidney injury because of known etiologies other than possible doxorubicin toxicosis were excluded. Variables were compared to identify risk factors. RESULTS: Mean age (±SD) was 10.9 years (±3.2). Cancer types included lymphoma (n = 36), sarcoma (n = 19) and carcinoma (n = 14). Chronic kidney disease was present in 29/70 (41%) cats before receiving doxorubicin. Of 70 cats, 24 (34%) developed an increase in serum creatinine concentration ≥0.3 mg/dL and 10 (14%) had an increase ≥50% from baseline. Mean time to increases in serum creatinine concentration ≥0.3 mg/dL from first administration of doxorubicin was 119.3 days (±89.7), with mean 2.8 (±1.2) doses administered. Neutropenia or anemia during chemotherapy and number of radiation therapy treatments under general anesthesia were risk factors for increases in serum creatinine concentration (P < .05). Cats receiving single agent doxorubicin had a higher likelihood of an increase in serum creatinine concentration ≥0.3 mg/dL from baseline than cats receiving CHOP-based chemotherapy protocols (OR 20.0, 95% CI 2.9-100). CONCLUSIONS AND CLINICAL IMPORTANCE: Progressive increases in serum creatinine concentration from baseline were common in cats receiving doxorubicin and associated risk factors were identified.

Application of therapeutic plasma exchange in dogs with immune-mediated thrombocytopenia.

Therapeutic plasma exchange (TPE) is an emerging treatment for dogs with immune-mediated diseases, but reports for treatment of immune-mediated thrombocytopenia (IMT) are lacking. These case reports illustrate the application of centrifugal TPE in 4 dogs with IMT. All dogs presented with severe hemorrhage requiring ≥1 blood transfusions, were unresponsive to conventional treatment or both. Dogs were treated with 3 sequential centrifugal TPE sessions, totaling 4.0 to 4.9 total plasma volumes exchanged per dog. In 3 dogs, TPE was associated with improvement in clinical manifestations of bleeding and platelet count in combination with immunosuppressive drugs. One dog was euthanized after 3 treatments because of persistent severe thrombocytopenia and hemorrhage. Preliminary observations indicate that TPE is safe and may be a useful adjunct in the management of IMT that is severe or refractory to traditional treatment.

Effects of famciclovir in cats with spontaneous acute upper respiratory tract disease.

OBJECTIVES: The aim of this study was to assess the effects of famciclovir administration in cats with spontaneously acquired acute upper respiratory tract disease. METHODS: Twenty-four kittens with clinical signs of acute upper respiratory tract disease were randomly allocated to receive doxycycline (5 mg/kg PO q12h) alone (group D; n = 12) or with famciclovir (90 mg/kg PO q12h; group DF; n = 12) for up to 3 weeks. Clinical disease severity was scored at study entry and daily thereafter. Oculo-oropharyngeal swabs collected at study entry and exit were assessed using quantitative PCR for nucleic acids of feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), Chlamydia felis, Bordetella bronchiseptica and Mycoplasma felis. RESULTS: The median (range) age of cats was 1.5 (1-6) months in group D vs 1.6 (1-5) months in group DF (P = 0.54). Pathogens detected in oculo-oropharyngeal swabs at study entry included FCV (n = 13/24; 54%), M felis (n = 8/24; 33%), FHV-1 (n = 7/24; 29%), C felis (n = 7/24; 29%) and B bronchiseptica (n = 3/24; 12%). Median (range) duration of clinical signs was 11.5 (3-21) days in group DF and 11 (3-21) days in group D (P = 0.75). Median (range) total disease score at the end of the study did not differ between groups (group D 1 [1-1] vs group DF 1 [1-3]; P = 0.08). CONCLUSIONS AND RELEVANCE: This study revealed no significant difference in response to therapy between cats treated with doxycycline alone or with famciclovir; cats improved rapidly in both groups. However, identification of FHV-1 DNA was relatively uncommon in this study and clinical trials focused on FHV-1-infected cats are warranted to better evaluate famciclovir efficacy.

Risk factors for positive urine cultures in cats with subcutaneous ureteral bypass and ureteral stents (2010-2016).

BACKGROUND: Ureteral stent and subcutaneous ureteral bypass (SUB) placement are commonly used for managing ureteral obstructions. Urinary tract infection (UTI) is a recognized complication. OBJECTIVES: To determine postoperative incidence of positive urine cultures in cats undergoing ureteral stent and SUB placement and to identify risk factors associated with positive urine cultures. DESIGN: Retrospective study. ANIMALS: Forty-three cats that underwent 48 surgical events. PROCEDURES: Medical records were reviewed. Cats were included if urine cultures were performed before and after surgery. Variables were compared to identify risk factors. RESULTS: Urine cultures were positive postoperatively pre-discharge in 5/20 (25%) cats. Median duration of follow-up post-discharge was 209 days (range, 11-2184 days), with a total of 143 urine cultures performed in cats post-discharge. Of these, 16 (11%) were positive in 12/48 (25%) cats. Nine different bacteria were identified; Enterococcus spp. (n = 8) predominated as monomicrobic or mixed infections. In 14/16 instances of positive urine cultures, affected cats had lower urinary tract signs, signs of pyelonephritis or both. Cats that received antibiotics postoperatively were significantly less likely to have a positive urine culture compared to those that did not (odds ratio, 0.2, 95% confidence interval, 0.05, 0.8, P = 0.02). Chronic kidney disease, renal implant type and postoperative urinary catheterization were not associated with positive urine cultures. CONCLUSIONS AND CLINICAL RELEVANCE: Postoperatively, occurrence of positive urine cultures was similar to previous reports. Subclinical bacteriuria was less common than UTI. Postoperative urinary catheterization has been speculated to increase risk of bacteriuria, but this was not the case in this cohort.

Management and monitoring of hyperthyroid cats: a survey of Australian veterinarians.

Objectives This study sought to evaluate how Australian veterinarians approach management and monitoring of feline hyperthyroidism and compare these results with a similar survey recently performed in the UK. Methods An invitation to complete an online survey was sent to veterinarians in all states and territories of Australia. The survey comprised questions relating to management of hyperthyroidism, use of antithyroid drugs vs radioiodine treatment vs surgical thyroidectomy, in addition to demographic information for respondents. Results A total of 546 clinicians completed the survey. The most commonly preferred treatments for long-term management of feline hyperthyroidism were antithyroid medications (305/546; 56%) and radioiodine (210/546; 38%), with substantially more respondents selecting radioiodine when cost was removed as a consideration (425/546; 78%). However, most respondents had treated or referred few cases for radioiodine (median 2). Most veterinarians (500/546; 92%) used antithyroid medications either long term or prior to definitive treatment of hyperthyroidism. For medical management, 45% (244/546) of veterinarians used twice-daily carbimazole. Half of respondents (274/546) aimed to maintain the total thyroxine concentration anywhere within the laboratory reference interval in hyperthyroid cats without chronic kidney disease. Blood pressure monitoring was uncommon. Surgical thyroidectomy was rarely performed. Conclusions and relevance Radioiodine was more frequently preferred by Australian veterinarians compared with those in the UK, likely associated with greater availability, reduced cost and shorter hospitalisation times in this jurisdiction, although antithyroid medications were the most frequently used treatment modality. Barriers remain to its utilisation, however, including perceived cost, misconceptions with regard to expected success rate and accessibility. Recent changes to recommendations on the management and monitoring of hyperthyroid cats do not appear to have been widely adopted by veterinarians at this time.

Investigating Coxiella burnetii infection in a breeding cattery at the centre of a Q fever outbreak.

The potential role of cats in transmitting Coxiella burnetii to humans was highlighted in a Q fever outbreak, linked to a caesarean section in a breeding queen, in an Australian small animal veterinary hospital. The objectives of this study were to evaluate the C burnetii seroreactivity of the breeding queen and other cats residing at the same breeding cattery (n = 27) and to evaluate C burnetii infection of the breeding queen by molecular and histological methods. Three assays [complement fixation test (CFT), indirect immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA)] were used for serological evaluation. Additionally, uterine and ovarian samples collected from the breeding queen 11 weeks post-parturition were assessed by routine and specialised histological methods and polymerase chain reaction. The breeding queen showed strong seropositivity using CFT (titre 1/32), IFA (titre phase I 1/8192 and phase II 1/8192) and ELISA; however, the reproductive tract showed no evidence of pathology or C burnetii infection. A number of cattery-confined cats were identified as seropositive to phase II and/or phase I C burnetii. Serological detection of C burnetii in a breeding cattery linked to a Q fever outbreak indicates likely infection by this bacterium in Australian feline populations, re-confirming the relevance of this zoonosis.