Frequency and risk factors for urinary tract infection in cats with diabetes mellitus

BACKGROUND: Identification and control of infections are important in the management of diabetic cats. Urinary tract infections have not been well characterized in diabetic cats. This retrospective study was performed to review and characterize urinary tract infections in diabetic cats. HYPOTHESIS: Urinary tract infections are common in diabetic cats. ANIMALS: A review was made of the medical records of 141 diabetic cats that had had urine obtained for culture by antepubic cystocentesis and that had not been treated with antibiotics, undergone urinary tract catheterization or urinary tract surgery within 2 weeks of urine collection or had urethral obstruction at the time of urine collection. METHODS: A review of medical records. RESULTS: Urinary tract infection was identified in 18 of 141 diabetic cats. Escherichia coli was the most common isolate (67%). Female cats were at increased risk (prevalence odds ratios [POR], 3.7; 95% confidence interval [CI], 1.3 to 10.2; P = .013). Clinical signs of lower urinary tract disease and findings on urine sediment examination were good predictors of positive urine cultures. CONCLUSIONS AND CLINICAL IMPORTANCE: Urinary tract infections are common in diabetic cats regardless of status of diabetic control, suggesting routine monitoring with urine sediment exams or urine culture is warranted.     

Clinical evaluation of cats with lower urinary tract disease.

In a prospective study, 141 cats with hematuria, dysuria, urethral obstruction, or combinations of these signs were evaluated by contemporary diagnostic methods and compared with 26 clinically normal cats (controls). Specific diagnosis was established in 45% (64/141) of cats affected with lower urinary tract disease (LUTD). Crystalline matrix plug-induced urethral obstruction was diagnosed in 21% (30/141) of affected cats, uroliths were identified in 21% (30/141) of affected cats, uroliths with concomitant bacterial urinary tract infection (UTI) were identified in less than 2% (2/141) of affected cats, and bacterial UTI alone was identified in less than 2% (2/141) of cats with LUTD. Viruses, mycoplasmas, and ureaplasmas were not isolated from urine samples collected from affected or control cats. Bovine herpesvirus 4 (BHV-4)-neutralizing antibodies were not detected in any serum sample obtained from cats with LUTD or from control cats. In contrast, BHV-4 antibodies were detected by an indirect immunofluorescent antibody (IFA) test in sera obtained from 31% (44/141) of cats with LUTD and 23% (6/26) of control cats. The prevalence of positive BHV-4 IFA test results in affected cats was not significantly different from that observed in control cats. Significant association was not apparent between positive BHV-4 IFA test results and clinical diagnosis, abnormal laboratory findings, or cat age. However, the number of male cats with BHV-4 IFA titer was significantly (P less than 0.02, chi 2 test) greater than that of female cats. Detection of BHV-4 antibodies in approximately 30% of affected and control cats indicates prior virus exposure. Further investigations are warranted to clarify the specific role of BHV-4 in cats with naturally acquired LUTD.     

Urinary tract infections in cats with hyperthyroidism, diabetes mellitus and chronic kidney disease

The prevalence of urinary tract infections (UTIs) in cats with hyperthyroidism (n=90), diabetes mellitus (DM) (n=57) and chronic kidney disease (CKD) (n=77) was evaluated retrospectively. It was found to be 12% in cats with hyperthyroidism and DM, respectively, and 22% in cats with CKD. Associations between UTIs and clinical signs, biochemical markers in serum and urinalyses were investigated. Many of the cats with UTIs had no clinical signs of lower urinary tract disease or changes in their laboratory values indicative of infection. Therefore, a urinalysis alone should not be used to exclude UTIs in these cats. UTIs are relatively common in cats with hyperthyroidism, DM and CKD, and urine cultures are recommended as part of the basic diagnostic plan for cats suspected of suffering from these conditions.     

Clinical utility of urine kidney injury molecule-1 (KIM-1) and gamma-glutamyl transferase (GGT) in the diagnosis of canine acute kidney injury

The aim of the present study was to evaluate the sensitivity and specificity of urine KIM-1 and urine GGT for the detection of naturally-occurring AKI, compared to healthy control dogs, dogs with stable chronic kidney disease (CKD), and dogs with lower urinary tract disorders (LUTD). The study included AKI grade 1 (n?=?21), AKI grade 2 to 5 (n?=?11), stable CKD (n?=?11), LUTD (n?=?15), and healthy dogs (n?=?37). Urine KIM-1 (ng/mg) and GGT (U/l) were normalized to urine creatinine (uCr). Statistically significant difference in KIM/uCr (p?=?0.0007) and GGT/uCr (p?<?0.0001) was found among the study groups. Area under the curve (AUC) for KIM-1/uCr and GGT/uCr as predictors of AKI was 0.81 and 0.91 respectively. Values of KIM-1/uCr of 0.73 ng/mg and of GGT/uCr of 54.33 showed the best combination of sensitivity and specificity (75% and 75.6%; 85.7% and 89.1% respectively). A significant positive correlation (p?<?0.0001) between KIM-1/uCr and GGT/uCr was found. Both urine KIM-1/uCr and GGT/uCr seemed to be potentially good markers for the diagnosis of AKI. Dogs with AKI showed significantly higher levels of urine KIM-1/uCr and urine GGT/uCr, compared with healthy dogs. Caution should be used in the evaluation of elevated urine KIM-1/uCr and GGT/uCr in dogs with pre-existing CKD and/or LUTD. Urine KIM-1/uCr and GGT/uCr might have a significant clinical utility, as complementary test, particularly in diagnosis early, non-azotemic stages of AKI.     

Clinical evaluation of commercially available urinary acidification diets in the management of idiopathic cystitis in cats

OBJECTIVE: To compare recurrence of signs of lower urinary tract disease (LUTD) in cats with idiopathic cystitis that were fed the dry or canned formulation of a commercial diet designed to result in production of an acidic urine. DESIGN: Prospective trial. ANIMALS: 54 client-owned cats with idiopathic cystitis that was diagnosed on the basis of a history of abnormal micturition, abnormal results on urinalysis, radiography, or cystoscopy, and lack of an alternative diagnosis. PROCEDURE: Cats were assigned to be fed the canned or dry formulation of the diet. Reevaluations conducted at 2 and 16 weeks, and at 6 and 12 months included a physical examination, CBC and serum biochemical analysis (except week 2), blood gas analysis, and urinalysis. Regular telephone contacts were also made. The study was discontinued after 12 months or if signs of LUTD recurred. RESULTS: Signs of LUTD did not recur in 16 of 18 cats fed the canned diet, and 17 of 28 cats fed the dry diet (chi 2, P < 0.05). Seven cats were reevaluated at recurrence. Owners of remaining cats in which signs of LUTD recurred declined to have their pets reexamined. A different problem (bacterial urinary tract infection) was identified in only 1 cat on reevaluation. Eight cats were lost to follow-up evaluation. CLINICAL IMPLICATIONS: Feeding this commercial canned urinary acidifying diet may reduce the proportion of cats with idiopathic cystitis that will have recurrence of signs of LUTD within a 12-month period.     

Evaluation of clinical signs and causes of lower urinary tract disease in European cats

OBJECTIVES: To investigate the clinical signs and causes of lower urinary tract disease (LUTD) in 77 cats. METHODS: Cats diagnosed with LUTD over a two-year period were included in the study. RESULTS: The study population comprised 67 male and 10 female cats. Uroliths occurred in 17 of the 77 cats (22 per cent), urethral plugs in eight cats (10 per cent) and urinary tract infection in six cats (8 per cent). In 44 cats (57 per cent), no specific cause for the disease was found and they were classified as having idiopathic LUTD. In two of the 77 cats (3 per cent) no definitive diagnosis was established. Pain was less common in cats with uroliths and haematuria was more often seen in cats with urinary tract infection. At presentation, urethral obstruction was diagnosed in 45 of the 77 cats (58 per cent). CLINICAL SIGNIFICANCE: The causes of LUTD found in cats in this study are similar to those that have been previously documented, and idiopathic LUTD is the most frequent diagnosis. However, the rate of urethral obstruction, particularly in cats with idiopathic LUTD, was higher than in other reports. The cause of this difference is unknown.     

ASSOCIATIONS BETWEEN ULTRASOUND AND CLINICAL FINDINGS IN 87 CATS WITH URETHRAL OBSTRUCTION

Urethral obstruction is a life‐threatening form of feline lower urinary tract disease. Ultrasonographic risk factors for reobstruction have not been previously reported. Purposes of this retrospective cross‐sectional study were to describe urinary tract ultrasound findings in cats following acute urethral obstruction and determine whether ultrasound findings were associated with reobstruction. Inclusion criteria were a physical examination and history consistent with urethral obstruction, an abdominal ultrasound including a full evaluation of the urinary system within 24 h of hospitalization, and no cystocentesis prior to ultrasound examination. Medical records for included cats were reviewed and presence of azotemia, hyperkalemia, positive urine culture, and duration of hospitalization were recorded. For medically treated cats with available outcome data, presence of reobstruction was also recorded. Ultrasound images were reviewed and urinary tract characteristics were recorded. A total of 87 cats met inclusion criteria. Common ultrasound findings for the bladder included echogenic urine sediment, bladder wall thickening, pericystic effusion, hyperechoic pericystic fat, and increased urinary echoes; and for the kidneys/ureters included pyelectasia, renomegaly, perirenal effusion, hyperechoic perirenal fat, and ureteral dilation. Six‐month postdischarge outcomes were available for 61 medically treated cats and 21 of these cats had reobstruction. No findings were associated with an increased risk of reobstruction. Ultrasonographic perirenal effusion was associated with severe hyperkalemia (P = 0.009, relative risk 5.75, 95% confidence interval [1.54–21.51]). Findings supported the use of ultrasound as an adjunct for treatment planning in cats presented with urethral obstruction but not as a method for predicting risk of reobstruction.     

Retrospective case-control study of the effects of long-term dosing with meloxicam on renal function in aged cats with degenerative joint disease

Medical records (2005-2009) of a feline-only practice were searched for cats with degenerative joint disease (DJD) treated using meloxicam. DJD was diagnosed by the presence of at least two of the following: (i) altered mobility (observed by the owner), (ii) abnormal physical findings, (iii) characteristic radiographic changes. The primary study cohort consisted of cats older than 7 years that had received meloxicam for variable intervals in excess of 6 months, and for which complete records were available. These cats were subdivided according to whether detectable chronic kidney disease (CKD) was present ('renal group'), or not ('non-renal group'), and, for the 'renal group', according to the cat's IRIS category. Serum biochemistry, urinalysis (including urine specific gravity [USG]), body mass and condition score were monitored regularly. Progression of CKD in the 'renal group' and 'non-renal group' of cats was compared to two groups of age- and IRIS-matched control cats not receiving meloxicam (from the same clinic, over the same time period). The study was thus a case-control design, with two study groups. Thirty-eight cats with DJD receiving long-term meloxicam therapy met the inclusion criteria. Of these, 22 cats had stable CKD at the start of treatment (stage 1, eight cats; stage 2, 13 cats; stage 3, one cat). No cats initially had an elevated urinary protein to creatinine ratio. The remaining 16 cats initially had normal renal analytes and adequately concentrated urine. The median age of the 'renal' and 'non-renal' meloxicam groups was 15.5 and 13.4 years, respectively. The median treatment duration was 467 days in the 'renal group' and 327 days in the 'non-renal group'. After titration (to the lowest effective dose), the median maintenance dose was 0.02 mg/kg/day in both groups (range 0.015-0.033 mg/kg/day). There was no difference in sequential serum creatinine concentration or USG measurements between the 'non-renal group' treated with meloxicam compared to control cats not treated with meloxicam. There was less progression of renal disease in the 'renal group' treated with meloxicam compared to the age- and IRIS-matched cats with CKD not given meloxicam. These results suggest that a long-term maintenance dose of 0.02 mg/kg of meloxicam can be safely administered to cats older than 7 years even if they have CKD, provided their overall clinical status is stable. Long-term meloxicam therapy may slow the progression of renal disease in some cats suffering from both CKD and DJD. Prospective studies are required to confirm these findings.     

Nutrition and aspects of feline lower urinary tract disease

Important causes of feline lower urinary tract disease (LUTD) that have been identified include urolithiasis and the formation of urethral plugs. In many cases, however, no specific cause of disease may be evident. Clinical studies in cats with apparently ‘idiopathic’ feline LUTD have suggested that some cases may respond to dietary modification, with diets designed to acidify urine, provide a good urine volume and relatively restricted magnesium intake. Nutritional research has predominantly focused on factors that may contribute to the formation of struvite uroliths, and has resulted in the development of specific recommendations for the management and subsequent prevention of recurrence of this condition. Urethral plugs have been less well studied, although recent clinical observations provide evidence that dietary modification may be of value in preventing their recurrence.     

Refinement of a commercial bench-top relaxin assay for pregnancy diagnosis using urine from domestic and nondomestic felids

Relaxin, a 6-kDa polypeptide hormone, is excreted in the urine during pregnancy in several mammalian species. A recent study showed that detection of urinary relaxin using a bench-top serum assay (Witness relaxin kit, Synbiotics Corp., San Diego, California 92127, USA) can be diagnostic for pregnancy in domestic cats (Felis silvestris catus), but it is unknown whether the bench-top kit is applicable with urine across felid species. Our objectives were to 1) examine modifications in urine processing to improve kit reliability in pregnant cats, 2) evaluate the impact of concentrating urine via filtration on relaxin detection, 3) assess the effect of sample freezing on relaxin concentrations, and 4) begin quantifying urinary relaxin levels in nondomestic felids. Urine and serum were collected from domestic cats and nondomestic cat species (Pallas' cat, Otocolobus manul; sand cat, Felis margarita; cheetah, Acinonyx jubatus; and lion, Panthera leo) at several times after breeding. Urine samples, subjected to various processing methods, were tested using the bench-top kit, and relaxin levels were later quantified via radioimmunoassay. For domestic cat urine samples, filtration and addition of protein/phosphate buffer improved the consistency of the relaxin kit for early pregnancy diagnosis. Urine freezing caused a slight (approximately 13%) but significant decrease in relaxin concentrations, but frozen-thawed samples still tested positive with the bench-top kit. In nondomestic felids, urinary relaxin immunoreactivity during pregnancy was similar to or higher than that of pregnant domestic cats, suggesting that relaxin is a reliable cross-species marker of pregnancy. Urinary relaxin was detectable using the bench-top kit in pregnant Pallas' cats, but urine samples from other species tested negative, regardless of processing methods. Findings suggest that measurement of urinary relaxin is a promising approach for noninvasive pregnancy diagnosis in exotic felids, but further assessment of urinary relaxin profiles among cat species and modification of the bench-top relaxin kit are warranted to improve cross-species utility.     

The Role of Viruses in Feline Lower Urinary Tract Disease

Viruses have been implicated as causative agents in the etiopathogenesis of some forms of feline lower urinary tract disease (LUTD). This hypothesis was supported by isolation of feline calicivirus, bovine herpesvirus 4 (strain FeCAHV), and feline syncytia-forming virus from cats with naturally occurring LUTD, and by experimental studies of induced viral urinary tract infection. Results of early clinical studies yielded contradictory results concerning the role of viruses in feline LUTD. However, recent detection of bovine herpesvirus 4 antibodies in feline serum samples and discovery of calicivirus-like particles in crystalline/matrix urethral plugs obtained from cats with naturally occurring LUTD, suggests the need to reexamine the etiopathologic role of viruses using contemporary methods of virus identification and localization.     

Clinical efficacy and palatability of pradofloxacin 2.5% oral suspension for the treatment of bacterial lower urinary tract infections in cats

BACKGROUND: Pradofloxacin is a 3rd generation veterinary fluoroquinolone designed to restrict the emergence of antimicrobial resistance during therapy. HYPOTHESIS: Pradofloxacin 2.5% oral suspension is a safe, efficacious, and palatable treatment for bacterial urinary tract infections (UTI) in cats. ANIMALS: Seventy-eight cats presented with lower urinary tract signs and were positive on bacterial culture of urine. METHODS: Cats were allocated into 3 treatment groups depending on bacterial susceptibility results: pradofloxacin (n = 27), doxycycline (n = 23), or amoxicillin-clavulanic acid (n = 28). All antimicrobials were presented in palatable liquid form. Posttreatment urine specimens were collected after completion of the course of treatment and submitted for bacterial culture and sensitivity. Owners were questioned before and after treatment about their experiences with administering oral medication to their cats. RESULTS: Posttreatment urine culture was negative in all cats in the pradofloxacin group, but there were 3 treatment failures in each of the other groups. Owners' perceptions of the difficulty of administering oral medication to their cats was more positive posttreatment than pretreatment (P = .001; P < .001). There was no difference in palatability among the treatment groups (P > .05). CONCLUSIONS AND CLINICAL IMPORTANCE: We conclude that pradofloxacin 2.5% oral suspension is a highly effective and safe antimicrobial treatment for bacterial lower urinary tract infection in cats, and that the palatable formulation optimizes owner compliance. These findings make pradofloxacin a useful addition to the veterinary formulary.     

Association of microalbuminuria and the urine albumin-to-creatinine ratio with systemic disease in cats

OBJECTIVE: To determine the diagnostic usefulness of semiquantitative and quantitative microalbuminuria assays and urine albumin-to-creatinine (UAC) ratio for detecting disease in cats. DESIGN: Prospective study. ANIMALS: 441 cats evaluated at a veterinary teaching hospital. PROCEDURES: Urine samples from cats for which a complete medical record was available were included. Urine dipstick results, urine protein-to-creatinine ratios (cutoffs, 0.1 and 0.4), semiquantitative and quantitative microalbuminuria assay results (cutoff, 1 mg/dL), and UAC ratio values (cutoffs, 100 and 200 mg/g) were determined. Clinical diagnoses determined within 3 months of enrollment were recorded. Sensitivity and specificity were determined with disease status used as the standard. The influences of clinical diagnosis, sex, age, serum urea nitrogen and creatinine concentrations, blood pressure, bacterial urine culture results, rectal temperature, pyuria, hematuria, and bacteriuria were evaluated by means of logistic regression. RESULTS: Of 441 cats that were eligible for inclusion, 40 were healthy and 401 had > or = 1 disease. Results of logistic regression indicated that significant associations existed for age, presence of disease, presence of urinary tract disease, azotemia, hematuria, and pyuria and results of 1 or both of the microalbuminuria assays. CONCLUSIONS and CLINICAL RELEVANCE: Microalbuminuria was associated with underlying disease. Sensitivity and specificity of the microalbuminuria assays for detection of systemic disease were superior to those of other tests. Microalbuminuria testing in conjunction with other screening procedures may increase identification of occult disease. A prospective study evaluating the predictive values of screening tests with and without microalbuminuria determination is needed to validate this recommendation.     

Survival in cats with naturally occurring chronic kidney disease (2000-2002)

Background: Duration of survival of cats with naturally occurring chronic kidney disease (CKD) is poorly characterized.
Hypothesis: Stage of kidney disease based on serum creatinine concentration (SCr) at the time of diagnosis and after correction of prerenal azotemia is strongly associated with duration of survival in cats.
Animals: Two hundred and eleven client-owned cats with naturally occurring CKD evaluated between April 2000 and January 2002.
Methods: Retrospective case review of 733 cats with SCr > 2.3 mg/dL. Examination of the medical records identified 211 cats that met all other inclusion and exclusion criteria for this study. Clinical characteristics, clinicopathologic data, and survival times were extracted from the medical record. Owners and referring veterinarians were contacted by phone to obtain follow-up if it was not documented in the record. Kaplan-Meier survival curves were performed to determine survival times for International Renal Interest Society (IRIS) stage both at diagnosis and at baseline (ie, after correction of prerenal azotemia).
Results: Median survival for cats in IRIS stage IIb at the time of diagnosis was 1,151 days (range 2–3,107), and was longer than survival in stage III (median 778, range 22–2,100) or stage IV (median 103, range 1–1,920) ( P -value < .0001). P -value for effect of stage at diagnosis was <.0001.
Conclusions and Clinical Importance: IRIS stage of CKD based on serum creatinine at the time of diagnosis is strongly predictive of survival in cats with naturally occurring CKD.     

The effect of boric acid on bacterial culture of canine and feline urine

Objective : To identify the optimal method of submission of canine and feline urine for bacterial culture. Methods : Cystocentesis samples from 250 animals (200 dogs, 50 cats) suspected of having urinary tract infections were collected. The reference aliquot, without preservative, was processed on site within 2 hours. Two further aliquots (one without preservative, one with boric acid) were stored at room temperature for up to 7 hours and then posted by guaranteed next day delivery to a commercial laboratory for analysis. Results : Forty‐seven of the samples were positive on culture in the reference test. There was no significant difference between reference test results and those of samples posted without preservative (P=0·39), but samples posted in boric acid were significantly less likely to give a positive result (P=0·01). Samples posted without preservative had a sensitivity of 82% and a specificity of 98%; for boric acid, sensitivity was 73% and specificity 99%. Clinical Significance : Postal urine samples should be submitted to the laboratory in a plain sterile tube.     

Underlying cause, pathophysiologic abnormalities, and response to treatment in cats with septic peritonitis: 51 cases (1990-2001)

OBJECTIVE: To determine the underlying cause, pathophysiologic abnormalities, and response to treatment in cats with septic peritonitis and identify differences between cats that survived following treatment and cats that did not survive despite treatment. DESIGN: Retrospective study. ANIMALS: 51 cats with septic peritonitis. PROCEDURE: Medical records were reviewed for clinical findings; results of clinicopathologic testing, microbial culture, and radiography; diagnosis; treatment; and outcome. RESULTS: Signs of pain during palpation of the abdomen were reported for only 29 of 47 (62%) cats. Eight (16%) cats had relative bradycardia (heart rate < 140 beats/min). The most commonly isolated organisms included Escherichia coli, Enterococcus spp, and Clostridium spp. The most common cause of peritonitis was gastrointestinal tract leakage (24 cats). No definitive source could be identified in 7 cats. Treatment, including exploratory surgery, was pursued in 23 cats, of which 16 (70%) survived and were discharged. There were no significant differences between survivors and nonsurvivors in regard to heart rate, age, rectal temperature, serum lactate concentration, WBC count, PCV, blood glucose concentration, or serum albumin concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that clinicopathologic abnormalities and outcome in cats with septic peritonitis are similar to those reported for dogs. However, certain features may be unique, including an absence of signs of pain during abdominal palpation, relative bradycardia, and apparent spontaneous peritonitis in some cats.     

Measurement of aldosterone in feline, canine and human urine

BACKGROUND: Systemic hypertension is an important problem in older cats associated with kidney disease and hypokalaemia, suggesting that excessive activity of the renin-angiotensin-aldosterone system might contribute to the hypertensive state. Fluctuations in plasma renin activity and plasma aldosterone concentrations complicate the interpretation of these assays. OBJECTIVES: The aim of this study was to determine whether measurement of urinary aldosterone excretion in cats aided the investigation of hypertension. METHODS: Urine concentrations of free (ethyl acetate extract) and 18-glucuronidated aldosterone (acid hydrolysis before extraction) were measured by radioimmunoassay in normal, normotensive and hypertensive azotaemic cats (n=11 per group). Urine samples from 11 healthy human volunteers and eight normal dogs were also analysed for comparison. Urinary aldosterone concentration was corrected for the urinary creatinine concentration. RESULTS: Cats excreted 7.3 times less free aldosterone than human beings, and no free aldosterone was detected in dog urine. Acid hydrolysis led to large increases in aldosterone recovery from both human beings and dog but not feline urine. No significant effect of hypertension or azotaemia on feline urinary aldosterone concentration was found. CLINICAL SIGNIFICANCE: Measurement of aldosterone in feline urine using the available methodology has limited or no utility in investigating feline hypertension.     

Incidence and prognostic value of low plasma ionized calcium concentration in cats with acute pancreatitis: 46 cases (1996-1998).

OBJECTIVE: To determine the incidence and prognostic significance of low plasma ionized calcium concentration in cats with clinical signs of acute pancreatitis (AP). DESIGN: Retrospective study. ANIMALS: 46 cats with AP and 92 control cats with nonpancreatic diseases. PROCEDURE: Medical records were reviewed, and results of clinicopathologic testing, including plasma ionized and total calcium concentrations, acid-base values, and electrolyte concentrations, were recorded. Cats with AP were grouped on the basis of outcome (survived vs died or were euthanatized), and plasma ionized calcium concentrations, acid-base values, and electrolyte concentrations were compared between groups. RESULTS: Serum total calcium concentration was low in 19 (41%) cats with AP, and plasma ionized calcium concentration was low in 28 (61%). Cats with AP had a significantly lower median plasma ionized calcium concentration (1.07 mmol/L) than did control cats (1.12 mmol/L). Nineteen (41%) cats with AP died or were euthanatized; these cats had a significantly lower median plasma ionized calcium concentration (1.00 mmol/L) than did cats that survived (1.12 mmol/L). Ten of the 13 cats with AP that had plasma ionized calcium concentrations < or = 1.00 mmol/L died or were euthanatized. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that low plasma ionized calcium concentration is common in cats with AP and is associated with a poorer outcome. A grave prognosis and aggressive medical treatment are warranted for cats with AP that have a plasma ionized calcium concentration < or = 1.00 mmol/L.     

Influence of the feed base excess on urine parameters in cats

In this study the base excess (BE) was used as a method to predict the influence of the food on the urinary pH on cats. Nine cat foods (six dry and three canned) were consecutively fed to eight cats. The urine pH, volume, specific gravity and water and food intake were determined daily. The base excess [BE; mmol/kg dry matter (DM)] was calculated from the compounds in the food (BE = 49.9*Ca+82.3*Mg*+43.5*Na+25.6*K-64.6*P-13.4*Met-16.6*Cys-28.2*Cl). The BE of the tested foods was between -287.35 and 133.38 mmol/kg DM. The mean urine pH varied between 5.76 (SD = 0.13) and 7.16 (SD = 0.22). The BE correlated with the mean urine pH (pH = 6.25+0.0023*BE; r = 0.74**). The urine volume (ml/kg BW/day) correlated significantly positive with the K- (r = 0.71**) and significantly negative with the P-content (r = -0.67**), the Ca-content (r = -0.50**) followed by the Mg-content (r = -0.36**) of the food. The correlation coefficients between the anions/cations in the food and the urine pH was for K 0.36**, for P -0.61**, the Met+Cys -0.60** and Cl -0.27**. In practice the correlation between urine pH and BE would help to pre-estimate the effect of food on the urine pH and to prevent urolith formation.