Diagnostic and predictive ability of hyperbilirubinemia severity in cats: A multicenter retrospective study.

BACKGROUND: Total serum bilirubin concentration (TBIL) can provide useful information on several pathophysiological conditions in cats. Nevertheless, whether the variable severity classification of hyperbilirubinemia can reliably indicate certain disease processes or predict a biliary obstruction (BO) has not been investigated. HYPOTHESIS/OBJECTIVE: Determine if hyperbilirubinemia of variable severity can assist clinicians to identify BO, which often is considered a surgical emergency. ANIMALS: Two-hundred sixteen client-owned cats. METHODS: Data were retrospectively collected from all cats (January 2015-August 2022) with an increased TBIL (>0.58 mg/dL [>10 µmol/L]) presented to 3 referral centers in the United Kingdom (UK). Presenting clinical features and diagnostic outcomes were collected. The predictive ability of TBIL to indicate BO was evaluated by multivariable binary logistic regression modeling and receiver operating characteristic (ROC) curves. RESULTS: Median TBIL was 1.73 mg/dL (range, 0.59-26.15; 29.5 µmol/L; range, 10.1-447.1) with severity classification of hyperbilirubinemia categorized as mild (>0.58-2.92 mg/dL; >10-50 µmol/L; 68.1%), moderate (>2.92-5.85 mg/dL; >50-100 µmol/L; 17.6%), severe (>5.85-11.70 mg/dL; >100-200 µmol/L; 9.7%) and very severe (>11.70 mg/dL; >200 µmol/L; 4.6%). Biliary obstruction was present in 17 (7.9%) cats, all of which received recommendation for emergency surgery. Median TBIL in cats with BO (9.69 mg/dL; 165.7 µmol/L) differed significantly from those without obstruction (1.51 mg/dL; 25.8 µmol/L; P < .01). The optimal TBIL cut-off to discriminate between cats with and without BO was ≥3.86 mg/dL (≥66 µmol/L) with a sensitivity of 94.1% and specificity of 82.4%. Using multivariable logistic regression, as age increased, the odds of BO increased significantly (odds ratio, 1.20; 95% confidence interval, 1.01-1.42; P = .04). CONCLUSIONS AND CLINICAL IMPORTANCE: As part of a thorough clinical assessment, the severity classification of hyperbilirubinemia has the potential to predict the likelihood of a BO and to discriminate between cats that may or may not require surgery for BO at a suggested cut-off of ≥3.86 mg/dL (≥66 µmol/L). Alongside TBIL, age is also useful when assessing for the likelihood of BO in a cat presented with hyperbilirubinemia.

Successful Use of Mycophenolate Mofetil as Adjunct to Prednisolone for Treatment of Acute Kidney Injury Secondary to Human Serum Albumin Administration in a Dog.

The use of human serum albumin (HSA) is described in dogs receiving critical care. However, despite the high degree of homology, anaphylactic and delayed hypersensitivity reactions are reported. Delayed type III hypersensitivity reactions can lead to glomerulonephritis and acute kidney injury (AKI). Undiluted 20% HSA was administered to a 4.8 yr old intact male Labrador Retriever with severe hypoalbuminemia, following surgical management of septic peritonitis of gastrointestinal origin. Nineteen days after HSA administration, the dog developed peracute high magnitude renal proteinuria and AKI. Rapid immunosuppression, using a combination of prednisolone and mycophenolate mofetil, resulted in full resolution of AKI, hypoalbuminemia, and proteinuria. Addition of mycophenolate mofetil may have resulted in the first documented case of full renal recovery from hypersensitivity-induced AKI caused by HSA administration.

Bacteriuria in Cystocentesis Samples from Cats in the United Kingdom: Prevalence, Bacterial Isolates, and Antimicrobial Susceptibilities.

Bacterial urinary tract infections (UTIs) have historically been reported to be uncommon in cats; however, recent studies showed a higher prevalence. Bacterial UTIs are one of the most common reasons for the use of antimicrobial drugs in veterinary medicine. Our aim was to investigate the prevalence of positive cultures in urine samples submitted to a UK laboratory for testing, as well as prevalence of bacterial species and their antimicrobial susceptibility to commonly used antibiotics. This was a retrospective analysis of positive cultures from feline urine samples collected by cystocentesis submitted over 14 months (January 2018-February 2019). A total of 2712 samples were reviewed, of which 425 documented a positive culture (15.7%) with a total of 444 bacterial isolates. E. coli (43.7%), other Enterobacterales (26.4%), Enterococcus species (14.9%) and Staphylococcus species (9.2%) were the most commonly isolated bacteria. E. coli most commonly showed resistance to cephalexin (20.7%) and amoxicillin (16.7%). Resistance was most commonly seen against amoxicillin (64.1%) and cephalexin (52.2%) in Enterobacterales. Enterococcus species most commonly showed resistance to trimethoprim/sulfamethoxazole (94.3%). Staphylococcus species most commonly showed resistance to amoxicillin (20%). This study showed significant resistance of bacteria found in feline urine samples in the UK to frequently used antibiotics.

Renal biomarkers in cats: A review of the current status in chronic kidney disease.

Serum creatinine concentration, the classical biomarker of chronic kidney disease (CKD) in cats, has important limitations that decrease its value as a biomarker of early CKD. Recently, serum symmetric dimethylarginine concentration was introduced as a novel glomerular filtration rate biomarker for the early detection of CKD in cats. However, data on its specificity are still limited. The limitations of conventional biomarkers and the desire for early therapeutic intervention in cats with CKD to improve outcomes have prompted the discovery and validation of novel renal biomarkers to detect glomerular or tubular dysfunction. Changes in the serum or urinary concentrations of these biomarkers may indicate early kidney damage or predict the progression of kidney before changes in conventional biomarkers are detectable. This review summarizes current knowledge on renal biomarkers in CKD in cats, a field that has progressed substantially over the last 5 years.

Liver-type fatty acid-binding protein and neutrophil gelatinase-associated lipocalin in cats with chronic kidney disease and hyperthyroidism.

BACKGROUND: Liver-type fatty acid-binding protein (L-FABP) and neutrophil gelatinase-associated lipocalin (NGAL) are candidate biomarkers for the detection of early chronic kidney disease (CKD) in cats. OBJECTIVE: To evaluate urinary and serum L-FABP and NGAL concentrations in CKD cats and in hyperthyroid cats before and after radioiodine (131 I) treatment. ANIMALS: Nine CKD cats, 45 healthy cats and hyperthyroid cats at 3 time points including before (T0, n = 49), 1 month (T1, n = 49), and 11 to 29 months after (T2, n = 26) 131 I treatment. METHODS: Cross-sectional and longitudinal study. Serum L-FABP (sL-FABP), serum NGAL (sNGAL), urinary L-FABP (uL-FABP), and urinary NGAL (uNGAL) were compared between the 3 groups and between hyperthyroid cats before and after treatment. Data are reported as median (min-max). RESULTS: CKD cats had significantly higher sL-FABP (13.50 [3.40-75.60] ng/ml) and uL-FABP/Cr (4.90 [0.97-2139.44] µg/g) than healthy cats (4.25 [1.34-23.25] ng/ml; P = .01 and 0.46 [0.18-9.13] µg/g; P < .001, respectively). Hyperthyroid cats at T0 had significantly higher uL-FABP/Cr (0.94 [0.15-896.00] µg/g) than healthy cats (P < .001), thereafter uL-FABP/Cr significantly decreased at T2 (0.54 [0.10-76.41] µg/g, P = .002). For the detection of CKD, uL-FABP/Cr had 100% (95% confidence interval [CI], 66.4-100.0) sensitivity and 93.2% (95% CI, 81.3-98.6) specificity. There were no significant differences in sNGAL and uNGAL/Cr between the 3 groups. CONCLUSIONS AND CLINICAL IMPORTANCE: L-FABP, but not NGAL, is a potential biomarker for the detection of early CKD in cats. Utility of uL-FABP to predict azotemia after treatment in hyperthyroid cats remains unknown.

Stability of glomerular and tubular renal injury biomarkers in canine urine after 4 years of storage.

Urine biomarkers are sensitive indicators of early-stage renal injury, consequently, research in this area is expanding in both human and veterinary medicine. However, studies investigating the impact of preanalytical factors, such as storage conditions, on urine biomarker concentrations are largely lacking in veterinary medicine. Therefore, we evaluated the stability of several renal injury biomarkers in canine urine after storage for 4 y at -72°C. Urine samples were collected from 26 dogs: 18 dogs with babesiosis and 8 healthy dogs. Concentrations of urine immunoglobulin G (uIgG), urine C-reactive protein (uCRP), and urine retinol-binding protein (uRBP) were measured, using validated commercial immunoassays, at the start of the study and 4 y later. To investigate the effect of long-term storage, absolute and relative differences between both measurements were compared. Additionally, dogs with babesiosis were compared with the healthy controls at both time points. Storage caused significant absolute and relative decreases in concentrations of all 3 biomarkers. Significant differences between dogs with babesiosis and healthy dogs were found in uIgG and uRBP at both times; however, the difference in uCRP between both groups lost significance after storage. Because the main goal of these urine biomarkers is to detect early-stage renal injury, the statistically significant decrease in their concentrations will be clinically relevant when a mild degree of renal injury is present. Our data indicate that the investigated urine biomarkers show significant decay after 4 y of storage at -72°C, adversely affecting their diagnostic utility.

Risk factors and clinical presentation of cats with feline idiopathic cystitis.

Feline idiopathic cystitis (FIC) is the most common cause of feline lower urinary tract disease (FLUTD). This retrospective, case-controlled study evaluated possible risk factors associated with FIC and compared different clinical presentations in 64 cats with FIC. Several risk factors known to be involved in FLUTD were identified as playing a role in FIC. Of the stressful situations considered, most did not occur with increased frequency in cats with FIC compared to controls, except for a house move. The presence of pyuria, haematuria and an increased urine protein:creatinine ratio were significantly higher in obstructed males compared with non-obstructed males. An obstruction was significantly more likely in cats with struvite crystalluria compared with cats without struvite crystalluria. These findings suggest that urethral plugs might be an important cause or contributing factor of obstruction in FIC. Episodes of FIC seem to occur mainly in susceptible cats in combination with a deficient environment.